Node Js Trading System

Sto usando Talib libreria di analisi tecnica per calcolare MACD ho usato i dati per calcolare AAPL MACD 8, 17, 9, ma i valori di Talib sono completamente diversi da Google e Yahoo Finance Qui è la mia javascript ho copiato ultimi AAPL dati stretti dal 2015/08/21 il valore. MACD di 2005/08/21 da Yahoo e Google finanza è -2 73, il valore Talib è 3 83 e con più dati MACD sono molto diversi quello che sto facendo male ho anche notato che Talib SMA e EMA danno gli stessi risultati a proposito, invertendo in Google classifiche MACD periodi lenti e veloci, non cambia la tabella di Yahoo does. asked 23 agosto 15 alla 17 16.Btw, hai visto questa discussione c'è spiegazione seguente la ragione per cui Yahoo e Google hanno diversi valori MACD è che stanno utilizzando la finestra diverse lunghezze Yahoo e Google don t usare 34 giorni ogni volta - che usano tutta la strada fino al primo dell'anno, una finestra che cresce in dimensioni ogni giorno di negoziazione Potrebbe provare Talib con tutti i dati dal 2015 -01-01 tartufi 25 agosto 15 a 15 22.25 punti dati non è sufficiente per ottenere un buon risultato di un calcolo MACD serie EMA si basa su più set di serie EMA è ricorsivo per il calcolo EMA MACD, id dire l'uso di almeno un anno s vale la pena di prezzo di chiusura data. smoke schermo testing di software tecnico indicatore può essere piuttosto arduo poiché è necessario essere certi che si sta utilizzando la stessa identica insieme di dati, garantire si ri iniziando con gli stessi valori di priming iniziali, ecc come il sistema di riferimento calcolo is. as fino ad ottenere i dati, Yahoo è una opzione, ovviamente, MarkIT offre anche una API che potrebbe funzionare che restituisce prices. what storico che ho notato è che sembra si ri alimentazione in un insieme di dati che inizia in corrispondenza del punto di dati più recenti e si muove indietro - cioè, l'indice 0 è 21-ago-indice 1 è 20 ago, indice 2 è 19 agosto, e così via è questo l'ordine che Talib si aspetta che il mio unico altro pensiero è quello di invertire l'ordine del set di dati, lasciando tutti gli altri ingressi lo stesso, e vedere quello che si ottiene lispHK01 25 agosto 15 al 11 39.I non sono uno specialista, ma ho capito è se si sta utilizzando 3 diversi periodi 8, 17 e 9 è necessario almeno il doppio dell'importo dei valori della vostra più lungo periodo al fine di calcolare l'istanza value. For corrente, immaginate di essere al tempo T e il calcolo del periodo di 17 per il valore di T-17 è necessario almeno 34 valori in modo da T-17 possono essere calcolati correttamente e T-16 fino a raggiungere i tuoi value. Does attuali che abbiano un senso. . 15. 45.000..Top Python Courses. The Top Java Tutorials. AWS Certified Solutions Architect - Associato 2017 Ryan Kroonenburg 100K 180.3D Animazione Nozioni di base Per Full Body e la creatura Meccanica Charlie Grübel 347 50.The Completa iOS Developer 10 Corso - Costruire 21 Applicazioni Rob Percival 43 2K 200.Photography MASTERCLASS Guida completa alla fotografia Phil Ebiner 1 67 6K 200.Body lingua per gli imprenditori Vanessa Van Edwards 1 20 8K 200.Affiliate Marketing - principianti s Guide to Guadagnare online Lisa Irby 5K 95.The ultima programmazione Python Tutorial Infinite Skills 22 5K 50.The Java Spring tutorial imparare Java s popolare Web Framework John Purcell 23 3K 35.Microsoft Excel 2010 Alta formazione Infinite Skills 73K 50.Acumen presenta Elizabeth Gilbert s Corsi di creatività Laboratorio Acumen 1 13 5K 100.Learn HTML5 programmazione da Learning Scratch Eduonix soluzioni 1 252 6K java tutorial per principianti completa John Purcell 668K. PLC programmazione From Scratch PLC I Paul Lynn 8 7K 100.. ..Perché Diavolo dovrei utilizzare un contenitore per caso per Tutorial. JavaScript s crescente popolarità ha portato con sé un sacco di cambiamenti, e il volto di sviluppo web oggi è drammaticamente differente Le cose che possiamo fare sul web al giorno d'oggi con JavaScript in esecuzione sul server, così come nel browser, erano difficili da immaginare solo alcuni anni fa, o sono stati incapsulati all'interno di ambienti in modalità sandbox come Flash o Java Applets. Before scavare in si potrebbe desiderare di leggere su i vantaggi di utilizzare JavaScript in tutto il pila che unifica la lingua e formato dati JSON, che consente di riutilizzare in modo ottimale le risorse per sviluppatori Poiché questo è più un vantaggio di JavaScript che specificamente, abbiamo vinto t discutiamo molto qui, ma SA vantaggio chiave per incorporare nodo del stack. As stati Wikipedia è una raccolta confezionato di motore JavaScript V8 di Google s, il livello di astrazione piattaforma libuv e una biblioteca di base, che è essa stessa scritto principalmente in JavaScript Oltre a ciò, si s la pena notare che Ryan Dahl, il creatore di mirava a creare in tempo reale siti web con capacità di spinta ispirato applicazioni come Gmail nel ha dato agli sviluppatori uno strumento per lavorare nel non-blocking, event-driven IO paradigm. After oltre 20 anni di apolide-web basato sul paradigma apolidi richiesta-risposta, finalmente abbiamo web le applicazioni con in tempo reale, a due vie connections. In una frase brilla nelle applicazioni web in tempo reale che impiegano la tecnologia push over WebSockets che cosa è così rivoluzionario che Ebbene, dopo oltre 20 anni di apolide-web basati sul paradigma apolidi richiesta-risposta , finalmente abbiamo applicazioni web con collegamenti in tempo reale, a due vie, in cui sia il client e il server può avviare la comunicazione, permettendo loro di scambiare dati liberamente Ciò è in netto contrasto con il tipico paradigma risposta web, dove il client avvia sempre di comunicazione Inoltre, è tutto basato sullo stack web aperto HTML, CSS e JS in esecuzione sulla porta standard 80.One potrebbe obiettare che noi ve avuto questo per anni, sotto forma di Flash e applet Java, ma in realtà, quelli erano gli ambienti solo in modalità sandbox utilizzando il web come un protocollo di trasporto da consegnare al cliente Inoltre, sono stati eseguiti in isolamento e spesso utilizzata oltre le porte non standard, che può aver richiesto i permessi aggiuntivi e such. With tutti i suoi vantaggi, ora gioca un ruolo critico nella la tecnologia pila di molte aziende di alto profilo che dipendono i suoi benefici unici la Fondazione ha consolidato tutto il meglio del pensiero intorno perché le imprese dovrebbero prendere in considerazione in una breve presentazione che può essere trovato sulla Fondazione s Case Studies page. In questo post, ho ll discutere non solo di come questi vantaggi si compiono, ma anche il motivo per cui si potrebbe desiderare di usare perché non usare alcuni dei classici modelli applicativi web come examples. How Does It work. The idea principale di uso non-blocking, event-driven IO di rimanere leggero ed efficiente a fronte di applicazioni in tempo reale ad alta intensità di dati che attraversano distribuito devices. That sa mouthful. What significa veramente è che non è una piattaforma d'argento-proiettile nuovo che dominerà il mondo dello sviluppo web, invece, sa piattaforma che riempie un particolare need. What in realtà significa che non è una piattaforma d'argento-proiettile nuovo che dominerà il mondo dello sviluppo web, invece, si sa piattaforma che colma una particolare esigenza e la comprensione di questo è assolutamente essenziale è sicuramente don t vuole usare per le operazioni CPU-intensive, infatti, utilizzando per il calcolo pesante annullare quasi tutti i suoi vantaggi Dove Nodo brilla davvero è nella costruzione, applicazioni di rete scalabili veloci, come s in grado di gestire un gran numero di connessioni simultanee con un throughput elevato, che equivale a elevata scalability. How funziona sotto il cofano è piuttosto interessante rispetto alle tecniche di web-serving tradizionali dove ogni richiesta di connessione genera un nuovo thread, riprendendo RAM di sistema e, infine, maxing-out per la quantità di RAM disponibile, opera su un single-thread, utilizzando non bloccante IO chiama, permettendo di supportare decine di migliaia di connessioni simultanee possedute in caso loop. A rapido calcolo partendo dal presupposto che ogni thread potenzialmente ha un accompagnamento 2 MB di memoria con esso, in esecuzione su un sistema di con 8 GB di RAM ci mette a un massimo teorico di 4.000 calcoli connessioni simultanee tratti da un articolo di Michael Abernethy s Proprio quello che è pubblicata da IBM developerWorks nel 2011, purtroppo, l'articolo non è più disponibile, più il costo del contesto-switching tra i thread che s lo scenario avete a che fare con il genere in tecniche di web-serving tradizionali evitando tutto ciò che, raggiunge livelli di scalabilità di oltre 1 milione di connessioni simultanee e oltre 600k WebSockets simultanei connections. There è, naturalmente, la questione della condivisione di un unico filo tra tutte le richieste dei clienti, ed è una potenziale trappola di scrivere applicazioni in primo luogo, il calcolo pesante potrebbe soffocare il filo per singolo nodo s e causare problemi per tutti i clienti più in seguito come le richieste in entrata saranno bloccate fino a quando ha detto che il calcolo è stato completato secondo luogo, gli sviluppatori hanno bisogno di essere molto attenti a non per consentire un'eccezione zampillante per il nucleo più in alto ciclo di eventi, che farà sì che l'istanza per terminare in modo efficace schiantarsi la tecnica program. The usata per evitare eccezioni ribolle in superficie sta passando errori al chiamante come parametri di callback, invece di gettarli , come in altri ambienti, anche se qualche eccezione non gestita riesce a ribollire, gli strumenti sono stati sviluppati per monitorare il processo ed effettuare la necessaria ripresa di un'istanza precipitato anche se probabilmente vinto t in grado di recuperare lo stato attuale della sessione utente, il più comune è il modulo o per sempre con un approccio diverso con strumenti di sistema esterno upstart e monit o anche solo upstart. NPM nodo pacchetto Manager. When discutere una cosa che sicuramente non dovrebbe essere omessa è il supporto integrato per la gestione dei pacchetti utilizzando il NPM strumento che viene fornito di default con ogni installazione L'idea di moduli NPM è del tutto simile a quella di Rubino gemme una serie di disposizione del pubblico, componenti riutilizzabili, disponibili attraverso una facile installazione tramite un archivio online, con la versione e la dipendenza management. A elenco completo degli confezionato I moduli possono essere trovati sul sito NPM o accessibili tramite lo strumento CLI NPM che automaticamente viene installato con l'ecosistema modulo è aperto a tutti, e chiunque può pubblicare il proprio modulo che verrà elencato nel repository NPM Una breve introduzione al NPM può essere trovato in un principiante s Guida e informazioni sui moduli editrici del NPM Publishing Tutorial. Some dei moduli NPM più utili oggi are. express - un framework di sviluppo web Sinatra di ispirazione e lo standard de-facto per la maggior parte delle applicazioni là fuori today. hapi - molto modulare e semplice da usare framework di configurazione-centric per la creazione di web e servizi applications. connect - Connect è un framework di server estensibile per fornire una raccolta di plugin ad alte prestazioni noti come middleware serve come base di partenza per Express. e sockjs - componente lato server dei due WebSockets componenti più comuni là fuori today. pug ex Jade - Uno dei motori di template popolari, ispirato da HAML, un in. mongodb di default e mongojs - wrapper MongoDB per fornire l'API per oggetto MongoDB database in. redis - Redis cliente library. lodash sottolineatura, - la cintura di utilità JavaScript underscore ha avviato il gioco, ma ha ottenuto rovesciato da uno dei suoi due controparti, dovuto principalmente a migliorare le prestazioni e implementation. forever modulare - Probabilmente il programma di utilità più comune per garantire che un determinato script nodo funziona continuamente Mantiene il vostro processo in produzione a fronte di qualsiasi failures. bluebird inaspettata - un pieno promesse caratterizzato da una implementazione con eccezionale performance. moment - un leggero libreria JavaScript data per l'analisi, la convalida, la manipolazione, e la formattazione dates. The elenco potrebbe continuare ci sono tonnellate di pacchetti realmente utili là fuori, a disposizione di tutti senza offesa per quelli che io ho here. Examples omesso di cui deve essere Used. Chat è il più tipico in tempo reale, l'applicazione multi-utente da IRC back in the day, attraverso molti protocolli proprietari e aperti in esecuzione su porte non standard, per la capacità di implementare tutto oggi con WebSockets corsa sopra la porta standard applicazione di chat 80.The è davvero l'esempio dolce-spot per lo sa leggero , ad alto traffico, data-intensive, ma l'applicazione di calcolo di elaborazione a basso che attraversa dispositivi distribuiti E 's anche un grande caso d'uso per l'apprendimento anche, come s semplice, ma copre la maggior parte dei paradigmi si ll mai utilizzati in una tipica applicazione. Sia s cercare di descrivere come si works. In l'esempio più semplice, abbiamo una sola chat sul nostro sito web dove le persone vengono e possono scambiare messaggi in uno-a-molti in realtà tutti la moda, per esempio, dire che abbiamo tre persone sul sito tutto collegato al nostro messaggio board. On lato server, abbiamo una semplice applicazione che implementa due cose 1 un gestore di richiesta GET che serve la pagina web contenente sia una message board e un pulsante Invia per inizializzare nuovi input messaggio e 2 un server WebSockets che ascolta per i nuovi messaggi emessi dal websocket clients. On lato client, abbiamo una pagina HTML con un paio di gestori di set up, uno per l'evento click pulsante Invia, che preleva il messaggio di input e lo invia lungo il websocket, e un altro che ascolta per i nuovi messaggi in arrivo sul client WebSockets cioè i messaggi inviati da altri utenti, che il server ora vuole il cliente a display. When uno dei client inserisce un messaggio, qui è ciò che happens. Browser cattura il pulsante Invia click through un gestore di JavaScript, prende il valore dal campo di input vale a dire il testo del messaggio, ed emette un messaggio websocket utilizzando il client websocket collegata al nostro server inizializzato sulla pagina web componente initialization. Server-lato della connessione websocket riceve il messaggio e lo inoltra a tutti gli altri client connessi utilizzando la trasmissione clienti method. All ricevono il nuovo messaggio come un messaggio push tramite un componente WebSockets lato client in esecuzione all'interno della pagina web che poi prendono il contenuto del messaggio e aggiornare la pagina web sul posto aggiungendo il nuovo messaggio al board. This è l'esempio più semplice per una soluzione più robusta si potrebbe utilizzare una cache semplice basata sul negozio Redis O in una soluzione ancora più avanzata, una coda di messaggi per gestire il routing dei messaggi ai clienti e una più robusta meccanismo di distribuzione che può coprire le perdite di connessione temporanea o messaggi di stoccaggio per i clienti registrati, mentre si ri offline Ma indipendentemente dei miglioramenti che si fanno, sarà ancora operativo sotto gli stessi principi di base reagire agli eventi, gestione di molti connessioni simultanee, e il mantenimento di fluidità l'utente experience. API in cima ad un oGGETTO DB. Although brilla davvero con applicazioni in tempo reale, esso s una misura del tutto naturale per esporre i dati da dati memorizzati oggetto DB esempio MongoDB JSON permettono di funzionare senza il disadattamento di impedenza e la conversione dei dati. per esempio, se si sta utilizzando Rails, si dovrebbe convertire da JSON ai modelli binari, poi esporle indietro come JSON sul quando i dati sono consumato da etc o addirittura pianura jQuery AJAX chiamate con si può semplicemente esporre gli oggetti JSON con una pausa API per il cliente di consumare Inoltre, è don t bisogno di preoccuparsi per la conversione tra JSON e quant'altro durante la lettura o la scrittura dal database se si sta utilizzando MongoDB In sintesi, si può evitare la necessità di conversioni multiple utilizzando una serializzazione dei dati uniforme formato attraverso il client, server, e database. QUEUED INPUTS. If si ri ricevendo una quantità elevata di dati simultanei, il database può diventare un collo di bottiglia Come illustrato in precedenza, possono facilmente gestire le connessioni simultanee stessi, ma perché l'accesso al database è un'operazione di blocco in questo caso, ci imbattiamo in problemi la soluzione è quella di riconoscere il comportamento del cliente s prima che i dati sono veramente scritto nel database. With questo approccio, il sistema mantiene la sua capacità di risposta sotto un carico pesante, che è particolarmente utile quando il cliente doesn t necessità ferma conferma di un dati di successo scrivere Esempi tipici includono la registrazione o la scrittura dei dati utente-tracciamento, sono trasformati in lotti e non utilizzati fino ad un momento successivo, così come le operazioni che don t bisogno di essere riflessa immediatamente come l'aggiornamento di un numero di Mi piace su Facebook dove eventuale consistenza così spesso usato in NoSQL mondo è acceptable. Data ottiene in coda attraverso un qualche tipo di caching o accodamento dei messaggi infrastrutture ad esempio RabbitMQ ZeroMQ e digerito da un processo batch-scrittura database separato, o di calcolo intensivo servizi di elaborazione di back-end, scritto in un migliore rendimento piattaforma per tali compiti comportamento simile può essere implementato con altri framework lingue, ma non sullo stesso hardware, con lo stesso alto, mantenuto throughput. In corto con nodo, si può spingere il database scrive a lato e trattare con loro più tardi, procedendo come se succeeded. DATA STREAMING. In più tradizionali piattaforme web, le richieste e le risposte sono trattati come evento isolato, infatti, si ri effettivamente flussi Questa osservazione può essere utilizzato per costruire alcune funzioni interessanti, ad esempio, che s possibile elaborare i file mentre si ri ancora caricato, in quanto i dati entra attraverso un ruscello e siamo in grado di elaborare in modo on-line Ciò potrebbe essere fatto per l'audio in tempo reale o codifica video e il proxy tra le diverse fonti di dati vedere la sezione successiva. è facilmente impiegato come proxy lato server dove può gestire una grande quantità di connessioni simultanee in maniera non bloccante 's particolarmente utile per il trasferimento di servizi diversi con differenti tempi di risposta, o raccogliere dati da sorgenti multiple points. An esempio si consideri un applicazione server-side comunicare con risorse di terze parti, tirando in dati provenienti da fonti diverse, o la memorizzazione di beni come immagini e video per il cloud services. Although proxy server dedicati di terze parti esistono, utilizzando Nodo invece potrebbe essere utile se l'infrastruttura è il proxy inesistente o se avete bisogno di una soluzione per lo sviluppo locale con questo, voglio dire che si potrebbe costruire una applicazione lato client con un server di sviluppo per le attività e il proxy spegnendo richieste API, mentre la produzione si d gestire tali interazioni con un proxy dedicato servizio di nginx, HAProxy, etc. BROKERAGE - Agente di cambio S DASHBOARD. Let s tornare al livello di applicazione un altro esempio in cui il software desktop domina, ma potrebbe essere facilmente sostituito con una soluzione web in tempo reale è un software broker di trading, utilizzato per monitorare le scorte prezzi, eseguono i calcoli di analisi tecnica, e creare grafici charts. Switching ad una soluzione web-based in tempo reale permetterebbe broker di passare facilmente workstation o luoghi di lavoro presto, potremmo iniziare a vedere sulla spiaggia in Florida o Ibiza o Bali. APPLICATION mONITORAGGIO DASHBOARD. Another caso d'uso comune in cui Nodo-con-web-socket adatta perfettamente il monitoraggio dei visitatori del sito web e la visualizzazione delle loro interazioni in real-time. You potrebbe essere raccogliendo statistiche in tempo reale dal vostro utente, o addirittura lo spostamento al prossimo livello con l'introduzione di interazioni mirati con i visitatori con l'apertura di un canale di comunicazione quando raggiungono un punto specifico nel vostro imbuto Se si ri interessati, questa idea è già productized da CANDDi. Imagine come si potrebbe migliorare il vostro business se si sapeva ciò che i visitatori erano facendo in tempo reale se si poteva visualizzare le loro interazioni con il tempo reale, le prese a due vie di ora si can. SYSTEM monitoraggio DASHBOARD. Now, lasciare che s visitare la parte dell'infrastruttura delle cose Immaginate, per esempio, un provider SaaS che vuole per offrire ai propri utenti una pagina di servizio di monitoraggio ad esempio GitHub s pagina di stato Con l'evento-ciclo, siamo in grado di creare un potente dashboard basata su web che controlla gli stati di servizi in modo asincrono e spinge i dati per i clienti utilizzando websockets. Both intra interna azienda e servizi pubblici stati possono essere segnalati dal vivo e in tempo reale utilizzando questa tecnologia push questa idea un po 'più avanti e cercare di immaginare un applicazioni di monitoraggio network Operations center NOC in un operatore di telecomunicazioni, di rete cloud hosting provider o qualche istituzione finanziaria, tutti eseguire sullo stack web aperto e sostenuto da WebSockets invece di Java e Java o Applets. Note Don t cercare di costruire sistemi hard real-time in Node ovvero sistemi che richiedono tempi di risposta coerenti Erlang è probabilmente una scelta migliore per quella classe di application. Where può essere Used. SERVER-SIDE applicazioni web. con può anche essere utilizzato per creare applicazioni web classici sul lato server Tuttavia, anche se possibile, questo paradigma di richiesta-risposta, in cui sarebbe stato portare in giro il formato HTML non è il più tipico caso d'uso ci sono argomenti da effettuare a favore e contro questo approccio Questi alcuni numeri di consider. If l'applicazione doesn t hanno alcun calcolo intensivo della CPU, si può costruire in Javascript top-to-bottom, anche fino al livello di database se si utilizza JSON stoccaggio oggetto di DB come MongoDB questo facilita lo sviluppo compresi significantly. Crawlers assunzione ricevere una risposta HTML completamente resa, che è molto più SEO-friendly rispetto, ad esempio, un'applicazione pagina singola o un WebSockets APP correre in cima of. Any CPU di calcolo intensivo bloccherà la reattività, quindi una piattaforma filettata è un approccio migliore alternativa, si potrebbe provare a scalare la computation. Using con un database relazionale è ancora piuttosto un dolore vedere di seguito per maggiori dettagli Fatevi un favore e prendere qualsiasi altro ambiente come Rails, Django, o MVC se si sta cercando di eseguire le operazioni relazionali. Un'alternativa a questi calcoli intensivi di CPU è quello di creare un ambiente di MQ-backed altamente scalabile con l'elaborazione back-end per mantenere nodo come impiegato frontale per gestire client richiede asynchronously. Where shouldn t essere Used. SERVER-LATO APPLICAZIONE WEB WA RELAZIONALE DB BEHINDparing con contro Ruby on Rails, per esempio, vi è una decisione pulita in favore di questi ultimi, quando si tratta di dati relazionali strumenti access. Relational DB per sono ancora nelle fasi iniziali si ri piuttosto immaturo e non come piacevole con cui lavorare D'altra parte, Rails fornisce automagicamente configurazione l'accesso ai dati a destra, fuori dalla scatola insieme con schema DB strumenti di supporto migrazioni e altre gemme gioco di parole Rails e dei suoi quadri pari avere matura e comprovata attivo o Data Mapper implementazioni di Data Access Layer, che si ll dolorosamente perdere se si tenta di replicare loro in puro JavaScript. Still, se si ri davvero incline a rimanere JS tutto-the-way e pronto a tirare fuori alcuni dei vostri capelli, tenere d'occhio Sequelize e Nodo ORM2 entrambi sono ancora immaturo, ma possono eventualmente recuperare. E 's possibile e non è raro usare Nodo esclusivamente come front-end, mantenendo le rotaie di back-end e il suo facile accesso a una DB. HEAVY relazionale CALCOLO lato server PROCESSING. When si tratta di computazione pesante, non è il migliore piattaforma intorno No, è sicuramente don t vuole costruire un server di Fibonacci computazione in in generale, qualsiasi operazione intensivo della CPU annulla beneficia tutto il throughput Node offre con la sua, non-blocking modello IO event-driven, perché le richieste in entrata vengono bloccati, mentre il filo è occupato con i tuoi number-crunching. As affermato in precedenza, è single-threaded e utilizza solo un singolo core della CPU quando si tratta di aggiungere la concorrenza su un server multi-core, c'è qualche lavoro svolto dal team principale nodo in la forma di un ref modulo di grappolo È anche possibile eseguire più istanze di server piuttosto facilmente dietro un proxy inverso via nginx. With clustering, si dovrebbe comunque scaricare tutti pesante il calcolo di processi in background scritti in un ambiente più adeguato per questo, e di farle comunicare via un server di coda di messaggi come RabbitMQ. Even se la vostra elaborazione in background può essere eseguito sullo stesso server inizialmente, un tale approccio ha il potenziale per molto elevata scalabilità tali servizi di elaborazione in background potrebbero essere facilmente distribuito ai server dei lavoratori separati, senza la necessità di configurare il carichi di corso di web servers. Of frontale, è d utilizzare lo stesso approccio anche su altre piattaforme, ma con si ottiene che l'alta produttività reqs sec noi ve parlato, come ogni richiesta è un piccolo compito gestito molto rapidamente e efficiently. We ve discusso dalla teoria alla pratica, a partire con i suoi obiettivi e le ambizioni, e termina con le sue macchie dolci e le insidie ​​Quando la gente incorrere in problemi con il nodo, si riduce quasi sempre al fatto che le operazioni di blocco sono la radice di ogni male 99 del Nodo abusi vengono come un nodo consequence. In diretta, le operazioni di blocco sono la radice di tutti i mali 99 di abusi Nodo essere una consequence. Remember diretta non è mai stato creato per risolvere il problema di scala di calcolo E 'stato creato per risolvere il problema di scala IO, che si realtà non well. Why utilizzare Se il caso d'uso non contiene operazioni CPU intensive né accedere alle risorse di blocco, è possibile sfruttare i vantaggi di e godere di applicazioni di rete veloci e scalabili Benvenuti al tempo reale web. About il profilo completo author. View. Membro dal 12 febbraio, 2013.Tomislav è un ingegnere del software, consulente tecnico e architetto con oltre 10 anni di esperienza si è specializzato in full-stack, altamente scalabile, in tempo reale, JavaScript e applicazioni, con l'esperienza passata in C, Java, e Ruby Lui è un professionista agile Kanban che ama collaborare su progetti di sviluppo click to continue. For DB relazionali sul nodo, ho like. Awesome articolo ho sicuramente d'accordo che ha alcuni casi di utilizzo davvero perfettamente adatto Comunque, io voglio commentare qualcosa che è un po 'un piccolo cruccio di mio - Vorrei che wouldn t e contrasto con un sistema tradizionale inesistente paglia-uomo nel modo in cui funziona 1 Nessun server genera un thread per ogni richiesta che utilizzano pool di thread o vasche di processo 2 You dire costo del cambio di contesto, come se si applica solo per le discussioni OS fotogrammi userspace hanno bisogno di essere salvati e caricati nello stesso modo in più il sistema operativo fa con poche istruzioni, sfruttando supporto specialistico dall'hardware - che userspace può t fare 3 Allo stesso modo , userspace discussioni I e cornici o chiusure se don t vuole parlare discussioni prendere risorse di memoria nello stesso modo thread del kernel fanno non s come se ogni thread sistema ha s limite stack completo assegnato, in modo che s un'analisi ingiusto sistemi normali hanno regolarmente più di 4000 senza venire da nessuna parte vicino a dove si ve ancorato esso 4 il problema BIG con single-thread concorrenza è la mancanza di parallelismo Certo, si può gestire migliaia di richieste al secondo, ma solo una CPU sul server 40 nucleo sta andando a fare qualsiasi lavoro in ogni modo, tutto quanto sopra è nei confronti di un paragrafo piuttosto minori nel vostro ottimo post Nodo isn t veramente colpevole di questo, è solo che non vi è un sacco di FUD là fuori intorno thread e processi che le persone spesso usano per giustificare disegni folli e di evitare le discussioni quando sono completamente l'approccio giusto per la maggior parte dei situations. All vostro consiglio su computazione applicazioni pesanti non potrebbe essere più sbagliato e 's certamente vero che il tentativo pesante di calcolo in linea con il ciclo di richiesta-risposta, è una cattiva idea , ma lo stesso si potrebbe dire di ambienti filettati Se si dispone di operazioni di CPU legato, è una buona idea di gestirli con l'operaio processi JavaScript e Nodo in particolare, sono in realtà molto adatto a gestire calcolo distribuito - in particolare con il buon supporto per funzionale stile di programmazione Se si scrivono algoritmi utilizzando funzioni pure e distribuire il carico di lavoro per i lavoratori, si può facilmente distribuire il carico di lavoro su cluster di rete Nodo s grande supporto per il networking rende un ambiente ideale sia per attività di elaborazione e orchestrazione, e s ordini di grandezza più veloce di rubino a both. Very utile Grazie lot. You certamente don t vuole bloccare qualsiasi processo che sta gestendo le richieste del server, ma che doesn t significa non dovreste fare calcoli pesanti dietro un server Fino a quando il processo di fare i calcoli pesanti è generato in modo asincrono dal processo server Ancora si potrebbe finire per bloccare il processo se si ritardo, ma questo è vero anche con la tradizionale server. This filettato sta per farmi fuori per essere un noob gigante, ma mi puoi dare un esempio di un blocco operation. Any tale sistema ibrido I m pensando Usa per elaborare una richiesta semplicemente ponendolo su una coda di processo, restituire un messaggio al client che indica qualcosa come calcolare poi è libero di continuare con la successiva richiesta di il-processo coda può quindi essere eseguito attraverso l'utilizzo di un filo differenza o discussioni addirittura multipli come e quando questi completo, mandano i loro risultati a coda di s che poi trasmetterlo al client originale Naturalmente questo significa qualche chiave ID deve accompagnare ogni elemento in questa coda per garantire la corretta dati vengono restituiti al client corretto Tutto ciò in questo modo possibile, o addirittura già implemented. Great articolo, thanks. Tomislav, grazie per questo molto ben scritto e conciso articolo Noi ve utilizziamo MongoDB e in combinazione con AngularJS per la utente di fronte a parte per 2 anni e riuscivo a immaginare di mai, mai, mai tornare a Flash, dopo 10 anni di esperienza o JEE RDMS Così si riduce ad un solo linguaggio di programmazione JS, un formato di dati JSON e un paradigma di programmazione asincrona, wow. That s di gran lunga la migliore spiegazione là fuori su ho finalmente capito che è molto utile in alcuni scenari e non solo una montatura Grazie mille questo era molto informative. Node funziona bene con i database relazionali, appena don t utilizzare un ORM SQL isn t così difficile da learn. True, ma ho pensato che come industria ha ottenuto oltre l'idea di scrivere tutto il codice SQL manualmente strumenti sono buoni per le operazioni più comuni, gli strumenti che solo uscire del modo in caso di necessità di scrivere manualmente alcune specifiche, altrimenti riducendo la possibilità di errori e problemi di sicurezza che accade con gli sviluppatori più giovani, che lo vogliamo o not. Hi Adin, mi permetta di commentare indietro 1 stesso scenario accade, ci sa quantità limitid di fili che servono numero limitato di clienti 2 3 referenziati spettacoli di presentazione alcune misure e numeri, si può essere del tutto proprio sulle parti interne, ma il quadro di massima comune si trova ancora come un confronto generale di come funzionano le cose tra questi due mondi 4 opzioni di parallelizzazione vengono discussi anche all'interno dell'articolo - come processi in background di lavoro, o più nodi processi dietro un proxy inverso, o con il nodo di clustering API, che è ancora in Sperimentale, ma ci sarà finalmente Grazie per i grandi commenti e le valutazioni di qualità sul articolo con informazioni aggiuntive che, apprezzo it. Yes, si può avere lavoratori più processi, anche comunicano attraverso Message Queue MQ I lavoratori possono essere processi nodo separato come nodo è a thread singolo, a meno di sperimentare il clustering API - mi rifugio t ancora provato come l'API è molto presto e probabilmente immmature, ma può essere qualsiasi altra lingua I ve lavorato su un tale sistema che riceve C su Mono per elaborazione in background in un calcolo CQRS architecture. Any distribuito che mantiene la CPU occupato fino calcolo è finito immaginare qualche operazione che richiede 2 secondi per eseguire il calcolo Hit che con 100 clienti - you get a 200-sec delay Note the article I have referenced, which explains the blocking of the event loop. Yes, that falls under the idea of having backend worker processes in a distributed system As the system is distributed, those workers can use any language platform, including Node. Thanks for your feedback I agree on that completely, for worker processes you could use JS when it fits, and that implies as that s what runs JS on the server, but you can also use other languages that do the particular work at hand fast. For ORMs in general, I just see them as a tool that can get something done quick for a newbie, but end up really gumming up the works later on The closest thing I use for an ORM is a PDO wrapper which I borrowed and rewrote from an old co-worker , that helps with writing PDO statements. Apologies for the wall of text Excellent discussion 1 Agreed But threads and processes are powerful tools That s why a hybrid of threads processes and event systems typically does best in the real world Like the much beloved nginx 2 3 Sorry, I may not have been clear When I said FUD regarding threads and processes, I meant the referenced presentation It s just a bunch of specifically tailored microbenchmarks designed to prove a certain point Which is fair, given that it sa lightning fair and can be a bit polemic In fact, it sa great talk But these synthetic micro-benchmarks are not the basis for a fair and through comparison To say the difference between nginx and apache benchmarks is purely because of context switching is an extreme oversimplification Nginx is specifically designed to serve requests really, really quickly in common circumstances IMO generally by a tight coupling with the latest OS event systems, etc You could specifically measure the overhead of context switching, and I would wager it s trivial 4 But then aren t you at the mercy of the horrible process overhead the referenced presentation talks about -- can t have it both ways To be clear, my position using threads processes or whatever is not in and of itself a problem There are way more important design factors there, the OS overhead of those entities is pretty trivial Hence I hate it when people adopt a silly design based on the idea thread-are-bad or processes-are-bad or some other such nonesense. Everything always needs to be put in the right context I have presented possible situations, to analyze each one deeply I d need a book - Still, I really appreciate your comments and insights, they are valuable addition to the article Thank you for those. When use as api server , and the back-end db is the bottleneck, if the clients are the other applications, not user interface, can we just let these client requests hang there waiting for db operation complete sine can handle massive concurrent connections easily Is a MQ necessary in this scenario In my opinion, is right the queue. ORM does not exist to make query languages easier , it sa tool used to encapsulate database concerns, isolating them from the application There are several benefits, but ultimately, it makes applications easier to test and maintain years down the road Excuse the tangent, nothing to do with node. Yes, you could, but Ruby would be a poor choice if your aim is performance. thank you for a great article By using the child process - would you be able to overcome the high computational blocking Fibonacci issue. any real life examples. What of the Facebook example you used When a user clicks on the like button there is an immediate acknowledgement but the data is written later Cant that be an example of node used with relational db Anyway what makes up the message queue. Maybe go-lang is alternative choice. This article is great, except for the part where it says don t use NodeJS for computation because it doesn t have threads Since when do we need threads Run child processes The only advantage to running threads over child processes is shared memory Last time I checked, any system large enough for this entire debate to be relevant anyway is going to span multiple servers anyway, their by nullifying any benefit of threads So, get it out of your head that NodeJS can t do CPU intensive work And, if you can t, contact and we can fix all the stuff you built wrong with NodeJS. One application that few people use, but could be really fanastic, is using NodeJS to build a desktop application There s plenty of packages out there - personally, I favour Node-Webkit. Hi, nice article However I would like to point one thing, NodeJS is not running in a single thread The programmer doesn t have to spawn new threads, they are handled by node itself on event basis NodeJS is evented, each function call per event will run in a separate thread That approach encourages writing lighter functions If your function does a lot of computation, reactor it into smaller ones and they all will run in separate threads Think about the example where you process file while streaming That is possible thanks to threads. Great article BTW, what software did you use to make the images wireframes. This is very well written Thank you for this. The technique used to avoid exceptions bubbling up to the surface is passing errors back to the caller as callback parameters Excuse me, but that seems misled In my understanding, Node-style ie the pattern of passing errors as the first param to callbacks are a side-effect of the event queue returning control as soon as possible to allow for concurrency itself rather than a design to avoid interrupting flow The fact that exceptions do not bubble are actually quite often a source of errors, especially to newcomers. Great Article Wondering who made the beautiful diagrams. Great article, thanks BTW , which tool do you use to draw the images. For those that are curious, it seems the images were created with Adobe Photoshop CC I checked this by looking at the EXIF data of one of the images File Size 61 kB File Type PNG MIME Type image png Image Width 624 Image Height 600 X Resolution 72 Y Resolution 72 Color Space sRGB Color Mode 3 Compression Deflate Inflate Orientation Horizontal normal XMP Toolkit Adobe XMP Core 5 5-c014 79 151481, 2013 03 13-12 09 15 Creator Tool Adobe Photoshop CC Macintosh. Also, the fact that javascript is not able to check type compliance introduces dificulty in expontaneous organization of huge number of coders updating the same codebase simultaneously. mmmm disagree, if you use correctly a good ORM take a look at Mature ORMs you get also a distributed cache of your Relational Database that allows you more performance for the same bucks and more scalability of your sistem ORM is not just for easing the life to newies It is non sense to use a non-blockin sistem such as if at the end you get blocked at your Database But using a ORM that way, is not for newbies. Glad you mention, most people don t mention this. I d rather keep Node decoupled from the browser and keep the flexibility of running the frontend on platforms that normally don t run Node like smartphones. For that matter, since you can do an async shell to a console application, you could easily write your worker in, for instance golang, and then use a generic pool to limit your cpu workers from there, you can shell out to a more efficient worker You can also do that for CPU intensive JS as well, I did this for my scrypt-js module there are binary modules that are more performant, but I wanted one without compiled dependencies It s not that hard to queue work to other systems, and no reason node can t be used to orchestrate said work. Could could use an intermediate system such as TypeScript, you can also use a linter jshint and even require a level of test coverage in order for release Getting 100 test coverage is generally very easy in scripted environments Would suggest looking into Mocha, Chai, and Proxyquire If you aren t writing unit tests, type safety really doesn t give you much. I am beginning to find quite interesting However, the paradigm it appears to be promoting is hardly new to IT In the mainframe communications world we called such capabilities, re-entrant , where a single process could handle a high level of calls to it Microsoft implemented similar capabilities with its Singleton object infrastructure and I imagine the Java world has done similar implementations Oddly enough, the Microsoft recommendation for enhancing scalability across the wires to back-end services was to promote the Single Call object structure or one object instance per calling request Thus, the argument made for is actually contrary to the Microsoft recommendation BTW, a recommendation I never quite understood In any event, as a business developer, I am not sure if I would find any use for a implementation, though our web designer may On another note, I would like to add my own opinion on the use of ORMs ORMs are great tools when faced with an existing database structure against the requirements of a new application as the ORM can handle a lot of the mundane, repetitive coding that is usually found with any database application However, because ORMs are high-level layers, they are usually not the most efficient options to use against databases whereas direct access through native providers are In many respects, better to do the repetitive coding for efficiency over applying a heavy-weight interim layer such as an ORM. Very interesting observation I d like someone to elaborate a bit more on that I would like a more concrete example, like some piece of concrete code calling an async heavy-computational function, and someone explaining what happens if that is run in a multicore equipment Does the thread that was sercing requests gets blocked Or another thread is used for that. Node is terrible as a web server Even the creator suggests that this is not what Node is intended for, and that it should be leveraged for it s strengths JavaScript Everything , just like worker processes, is ludicrous. This is ridiculous Node was built with the web as first class, and it excels as a web server It is rapidly replacing Ruby and PHP in many enterprise organizations because it has demonstrably boosted both application performance reduced page-load times, etc and developer productivity. You can in fact create multi-threaded servers using to offer more stable performance but it does take a lot of extra work see the built-in cluster module and the childprocess module I have created a framework which runs on multiple CPU cores and solves much of the issues discussed in this post Check it out. Connor James Leech. does something like solve the node relational database issue. Yes - see the queue pre-forked worker pool approach adopted by Summarised here. yeah, I was wondering about it too great visual awesome post. Erick Ruiz de Chavez. Just to complement what Tracker1 disqus said on his comment, JavaScript is usually criticized about the type checking and many other misunderstood features, like this , but the truth is that JavaScript is just very different to what most of the developers are used to do, and most of the developers who sadly have bad comments about it are just those who haven t had the interest or the time to understand how it really works JavaScript development is not only about the language itself but also about the tools you use to work with it, to mention some more you should really take a look at Grunt, Uglify, Yeoman, CoffeScript, etc. Erick Ruiz de Chavez. I might as well make myself a giant noob, but to put a quick example, any disk IO operation is considered a blocking operation as it has to perform a physical operation to read some data from the disk Another blocking operation example is querying a DB, where you basically have to wait for the response before doing anything else I d say, any sort of computational operation will be as blocking as the time it takes to complete In any of the above examples, you usually have your blocking request on line A and line B wont be executed until line A is completed instead is asynchronous, so line A is requested and then queued, and line B is executed no matter if line A is completed or not when line A is complete, you are notified either with a callback or with an event and then you can continue doing whatever you need to do with such result. Very helpful article. npm install felixge node-mysql That might be the most useful repository I ve seen in ages. Erick Ruiz de Chavez. I have a small example of mysql and at. How about Why the hell would I read an article without an obvious date and time stamp. Nice article, indeed But, hfuti disqus, you re wrong in saying NodeJS is not running in a single thread each function call per event will run in a separate thread As far as I understood, the main NodeJS event loop consuming your JS code in fact runs in a single thread All potentially blocking and or long-running tasks like disk IO is delegated to and executed by libuv as part of the node runtime engine which spawns a limited number of threads made available as thread pool Said this, it s obvious that the main event loop thread is not affected or blocked by other yet again asynchronous code execution So, for example, file IO with the fs module itself is implemented in a non-blocking manner - in the end as good as the OS kernel allows non-blocking operations Of course foreign processes or threads could always be spawned by custom modules or 3rd party services worker processes And yes, there are runtime env projects handling more than one node process and their threads on the same machine or cpu cluster But that s another story Feel free to correct me if I m wrong. This is fantastic. Very well written article You put a lot of thought into it Quick node express question I am I am adding rapid data entry, not batch, data entry to my system I have a form mfntapes that works great I have a test form joe the prompts for the number of times I want to call the mfntapes form The gist contains the code, fails to work, the after prompting for cnt attempts to call for mfntapes cnt times The question is how to call form mfntapes x number of times where x is a vairable See lines 45-55 of. ORM for real projects are useless hone. Nice article - SERVER-SIDE WEB APPLICATION WA RELATIONAL DB BEHIND I wonder why Node is not good for that You have promise based SQL libraries like Knex which enables non-blocking queries Node has no opposition with relational databases it has no interest with blocking IO drivers only Relational or not relational. I wish NodeJS was not almost systematicallty presented as THE de facto alternative to the traditional threaded webserver Async IO is not exclusive to NodeJS Most major languages out there - including Java and PHP - have async IO frameworks similar to NodeJS This wiki page lists most of them I m not saying NodeJS doesn t have its merit, but I m sick and tired of seeing people flocking to it as if it s the only async IO stack available, and the only alternative to the good ol PHP or Rails stack To be honest, we may be stuck with Javascript on the browser, and will be for a very long time except if Javascript becomes just another target platform language thanks to but I can t come up with any good reason to use it on the server side in favor to other available languages Most of the alternatives are just way better as a language, have better standard libraries, tools and resources Please stop spreading Javascript on the server, it s creepy p. Jarle Leopold Moe. How would you upload files What about Directory integration Active Directory, Open Directory What about communication with external services All request depending on a response from any of these types of services would block the calls is single-threaded it s only applicable for certain types of tasks. These re great examples of why Node is so much better than the competition at web services None of thee are blocking operations in Node They re asynchronous While other servers waste resources spinning off separate threads, Node fires off an event-driven asynchronous operation and keeps taking more requests in the meantime The practical upshot is that porting web services from PHP or Ruby can deliver between 2x and 10x improvements in simultaneous connections and typically 30 - 60 improvements in average response times Lots of big companies are doing web Node projects just for these reasons, including Adobe, Paypal, eBay, Walmart, Yahoo Groupon, Under , etc. very nice article and very clear thought regarding where to use and where not. Every major application development platform has already had support for HTML5 for the past several years, including websockets for bi-directional communication Add to this the strong types, multi - threading and the tons of other stuff that languages such as Java have to offer and I seriously question why anyone would waste their time using this. Just want to mention that node is not the only server side option for javascript especially since oracle put the nashorn javascript engine on the jdk Now you can also use all the jvm goodness from javascript we are using vert x as the async server and nashorn to use javascript You can see some code samples in this module the project site is. This is an amazing overview Thank you. Very well written Thanks for sharing. I m with you For trivial application an ORM is fine You have to remember that most devs really only have experience with trivial applications So they will argue for an ORM because they can t learn SQL or don t have the time or staff to right stored procs And they have never heard of Memcached and so think the ORM is a cache what ever And the weirdest excuse I hear is about decoupling The ORMs I have had the misfortune of running across do the opposite They very much tightly couple the UI to the database ORM layers are large and buggy So how do you test it Yeah, good luck unit testing it which you have to do because they are buggy. If you are integrating with AD then you are probably in a Microsoft shop And if you are uploading files to a web server then your environment isn t very sophisticated So for you, you probably should just stick with IIS and. Microsoft public recommendations for architecture are a joke Microsoft is a marketing and licensing company They are not a tech company primarily. If you have a huge number of coders updating the same codebase simultaneously you have larger problems Dev teams don t scale well I would run With too many cooks in the kitchen the broth will spoil There is going to be no accountability and no responsibility with that many people contributing. Why Node is different - using bar as analogy. a href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href aa href here aa href here aa href aa href a. Just to let you know you have support support in How it works under-the-hood is pretty interesting Compared to traditional web-serving techniques where each connection request spawns a new thread, taking up system RAM and eventually maxing-out at the amount of RAM available, operates on a single-thread, using non - blocking IO calls, allowing it to support support tens of thousands of concurrent connections held in the event loop. Isn t it possible to get the date of posting of your article or all your posts for that matter It is really disturbing to read technical posts without dates thanks. You mention is good for a chat application because it s not CPU intensive I can t think of too many use cases that don t require much CPU For example, could Twitter be built with Node It seems there sa lot of computation required just to generate your feed uses certainly can t be so narrow. Great article Thanks There s an old joke you re not a paranoid if they re really out to get you That s the attitude that should be taken when it comes to Web application security One thing that bothers me about is that I have no insight into how secure it is When an environment like Grails, where I have Java Groovy running on Tomcat I have some confidence in Tomcat security, if for no other reason than the fact that Tomcat has been around a long time and has evolved This isn t true with I was also looking at the libraries At least for the file access, it appears to be nothing more than a thin layer over the POSIX file system calls I like the Java or even the C file abstractions more The main argument that I see for made in this post is that it has really lightweight threads and that you can have JavaScrip everywhere This last issue is an attraction for those who only know JavaScript As far as the light weight threads, this is not so much a language issue as a platform support issue It should be possible to support this kind of thread model in another language. Toptal designer did the design for them. your comment is ridiculous too, ORM is not a everyone s accepted pattern. The irony is that lambda s aka, anonymous methods are the basis of both javascript and the preferred technique for C s multiple implementation of the same callback pattern, albeit with full type safety In fact node s major characteristics 2-way, lightweight, asynchronous has effectively been implemented in C as SignalR , and there are several language features which are both asynchronous and natively multithreaded, unlike Now I could understand if your experience with ORM s was limited to Hibernate absolutely awful, one of the worst implementations of a major concept I ve ever had the displeasure to work with or even EF, which at least is fairly powerful and expressive due to LINQ, if data nanny overkill But a micro-ORM like Dapper gives you all the flexibility and power of direct SQL with the benefits of rich data manipulation via objects, and is fast, very fast And I m sorry, but OOP is a well proven, very effective design strategy if you know what you are doing, ie you are a pro I see three major problems with the approach that no one seems to have a good answer for So you start with the premise that there are such inefficiencies in waiting for IO that there is a huge potential there So yeah, you ve got great concurrency, right until you get to the first blocking library, a database, a file server, etc, which is practically every major piece of functionality written So it s just hurry up and wait for 10,000 connections instead of 100, ok that s something, but where does it get you So then you start rewriting all those services asynchronously , but that s just a snake eating its own tail, because that s hurry up and wait too Because in the end every database on earth ultimately comes to a magnetic arm skipping across a disk or reading solid state memory, and that s assuming you re on the same machine, as opposed to distributing data across a pool of far slower network connections Then you have the single threaded issue There is probably no more misused language than Javascript because the barriers of entry are so low And while early adopters might understand a bad practice when they see one, most javascript programmers simply have no idea what they are doing Thirdly, Javascript is not exactly a particularly fast language, so the advice seems to be don t do compute intensive tasks Where does that get you So you end up with an elegant solution to one category of issues, but you re trapped there, with no way out of the non-compute intensive, hurry up and wait ghetto. Wow, that is one seriously ignorant statement Uploading files to webservers is THE stated rational of s inventor for why he wanted a non-blocking library So when you fanboi s break out of the single threaded, slow dynamic world of cut and paste code with zero type safety, multithreading, and only one trick pony lambdas to match s multiple asynchronous capablities, all so that you can get 10x more users to hurry up and wait for IO , then you can lecture us about sophistication The framework has a vastly more advanced feature set than any language you can name, period, and IIS, properly configured, can beat the piss out of Apache and can readily match nginx as a reverse proxy or for static content In the end you ve got several problems which are intractable 1 Javascript is slow, and your technology of choice is single-threaded, so intensive compute tasks are off the table 2 Javascript debugging and testing blows in comparison with any typed language Pro s use extensive testing, not fly by the pants hey it works 3 The everything is modular approach is not an architecture, it s an invitation to chaos, like Perl or PHP 4 Concurrency doesn t buy you crap if all you are doing is waiting for some other IO bound process, which is pretty much everything worth doing with computers 5 The quality and experience of many javascript programmers not programmers necessarily, but it s popularity will bring them is remarkably poor, as demonstrated by comments in which fanboi s prove that they have no idea how other systems that actually don t ignore any computing problem they can t solve work. ORM is just a work around for the problem of impedance mismatch, nothing else Its not big deal, about OO its a cross paradigm like AOP and its not really based in nothing else beyond encapsulation Without procedural paradigm OO does nothing, every real skilled programmer already knows that. Impedance mismatch involves all sorts of ramifications, especially in regards to maintainability, portability, extensibility and performance To quote Ethan above since my explanation obviously didn t take it sa tool used to encapsulate database concerns, isolating them from the application There are several benefits, but ultimately, it makes applications easier to test and maintain years down the road about OO its a cross paradigm like AOP and its not really based in nothing else beyond encapsulation Without procedural paradigm OO does nothing Ok, I ll be sure to spread the word that we should stop fooling around with all this esoteric OOP stuff and get back to a language that lets us do everything vis-a-vis encapsulation VB6 You d think a Javascript programmer might want to mention inheritance, if not polymorphism, since javascript has a relatively unusual mechanism for it prototypes. A singleton is an instantiable non - static object with a private constructor so that only a single instance can be created Imagine an instance class with a static property exposing an instance of itself that depends upon a private instance constructor It was actually implemented in Java before existed Perhaps what you are thinking of is a non-blocking Callback mechanism, which is handled in C via delegates, events multicast delegates and the new async and await keywords that transform standard C into a lambda to be executed at compile time It also handles multi-threaded asynchronous operations via it s Parallel extensions, which permit spreading load across multiple threads cores as long as that work is not serial in nature Also, I would encourage you to check out a micro-ORM like Dapper It s far less comprehensive than EF, but it s far more flexible and gets out of the way, plus it s significantly more efficient than Hibernate and EF about 5x faster for reads. Yes this article rocked tits Esp good for a Croat with ESL nodeboy. So after reading your article I still havent figured out why Node js want to reinvent the wheel I still think node js and the likes are crap. A great introduction to find out what it is JavaScript and once the answer to from a href bagaimana tips mengatasi wanita frigid a. Noob questions Um, isn t the ease with which you can move request data ie untrusted data into database where data is assumed to be trusted a big hazard How do you ensure that you never forget to inspect every piece of incoming data when it arrives, before you start trusting it Generally, I would assume something as popular as would have thought of this, but I remember back when Rails had blanket model update That changed real quick when Github s use of this feature was exploited fortunately, by a whitehat Also, of course, just because you add a conversion speed bump does not mean that people won t make mistakes, but at least they re more likely to give it some thought, which probably means they re going to make less mistakes. I don t understand the angst against using an ORM Were you in a proper environment where concerns were separated The ones bashing ORM just sound like they don t know what they re doing or how to engineer proper software Why on earth would I want to go from writing software in Java C whatever to drop into SQL where it is hard to version , properly test, and can apparently cause severe brain damage Everything is a double edged sword - an implementation or a convention like using an ORM over raw SQL really doesn t matter Depending on the situation raw SQL might be best it might be better to use a NoSQL store maybe an ORM is fine Usually, from my experience, I can tell you that an ORM is better for a lot of reasons, and they have been relayed by MI spent the time to write my own libraries to abstract vendor specific implementations and you need to create your own mappings You can easily spawn from a certain state or use existing data structures It took time to write my libraries and it was not easy at all to do it but it was well worth my time to do it since I can now reuse my libraries Is it the BEST I don t know I like it but I certainly won t go around to arbitrary technical articles that have nothing to do about SQL and post something like Yes this technology is good but stay away from raw SQL I just don t see a need to be bashing anything here, especially an ORM when the article is exclusively about JS and NodeJS. Probably one of the main points of this article, that gives Node is supposed scalability, is the offloading to a Queue or Service Bus that leads to asynchronous processing That is a well proven architectural pattern, available in many languages, is especially used in CQRS Command Query Responsibility Segregation with Event Sourcing, is very well suited to be used by technologies such Reactive Extensions that provide considerably greater functionality and flexibility than Node Asynchronous programming and handling its pitfalls has been around without Node for years, if you had knowledge of enterprise development As for the hate against ORMs you guys crticising it seem to be moving from front-end development into an area where you have no knowledge or expertise in OO, BDD, TDD or any other proven Enterprise level methodology No concept of integration other than Twitter feeds No experience of complex Workflow or scalable caching This is one of the dangers - you know JavaScript, and a bit of SQL So everything else is superfluous - until you need it, such as the attempts to bring an element of type checking to JavaScript Seriously, each technology has its place, but there is no one size fits all approach Appreciate the strengths of each technology, and use them where appropriate. Great introduction to Thanks, i samo naprjed. Because they suck for a complex application Sure if your scenario where you spent all this time trying to make the ORM work the way you need it to, you could have just put that same effort into writing the SQL properly and making sure it s organized etc and you would be further along in the project and have more control over the application ORM s are great at saving time on a small to medium scale project, but once you delve into more complex and larger applications , you re going to spend either AA lot of time coding to make the ORM work the way you need it or B Just decide to write the SQL yourself because the time it takes to make the tool work how you need it just isn t worth it. Very great post you add. JavaScript is better than some of the other programming languages therefore a href cara menghilangkan gatal keputihan a better fit with JavaScript. Great, informative article Thanks for sharing this a href Unlockpwd a. Its very good post thanks. Pot , meet kettle Those may be intractable problems if any of them were true None of them are 1 a JavaScript is all JIT these days and delivers 1-2x native code performance faster than any other dynamic language I m aware of b Non-blocking by default can deliver orders-of-magnitude improvements in code efficiency - transparently 2 Almost all modern editors support type inference for JS ESLint, Closure Compiler, and a number of other options offer sophisticated static analysis capabilities TypeScript even offers a nice structural type system 3 The opposite of modular is a tightly coupled monolith That sa bad idea in ANY language 4 if all you are doing is waiting for some other IO bound process - Non-blocking by default means you re NEVER waiting for some other IO bound process That s why Node delivers such huge improvements on resource utilization 5 2006 called They want their language-snob attitude back The days when serious engineers considered JS to be a toy are long since over JS powers sophisticated enterprise applications at just about every fortune 500 today Additional point JS is the only language with fully native support for isomorphic code meaning you reuse most of your application on both servers and clients You can write JS ONCE, and it will power the server, the web browser, and mobile devices including iOS and Android See React Native.1 1 -2x native code performance Do the electrons run faster on node code Not a good start 2 Type inference is mapping variable declarations to types without explicit syntax, iea it requires actual types, and b compilers enforce type safety, not editors And you can dress it up any way you want, but there is no way to enforce sophisticated state analysis with slop-tastic dictionaries of whatever stored in strings functional delegates Also, Typescript is not Javascript, it is Javascript with a half-assed type system pasted on top Even Google is abandoning Js for Typescript in Angular 2 0 Why Because Google has decided that an untyped system is insufficient for serious work But is that type system anywhere near as sophisticated as a compiled language Nope, not even close 3 You are misunderstanding what I was characterizing as modular design The alternative is not monolithic code, but encapsulation, specialization via inheritance or prototyping , polymorphism, and externalizing dependencies via IoC The alternative is SOLID, ie modern Object Orientation 4 Your process may not be waiting, but your customers are waiting for the callback My point is that being able to serve more requests doesn t do you any good if every served request then has to wait on yet another operation In the end, somewhere somehow, you will eventually be going to a disk or waiting for IO, because that s where the information the customer wants lives 5 I didn t say that JavaScript was a toy language, I said that most JavaScript developers are well-meaning, cut and paste amateurs, and they will invade the ranks of developers as it becomes more popular I ll take a strong type system over full native support that s not native for isometric code that can run on clients or servers you say that like that sa good thing any day Wow, Js on android and iOS I guess the days of Apple adding another strongly typed, native language for iOS are over sarc Obviously you ve never heard of Mono, the cross platform that compiles and runs on every major OS, produces native runtimes for all three major mobile platforms, and runs on everything from beowulf clusters to wearable devices This is why we don t respect you You don t know or understand anything that came before, or anything outside of your javascript bubble You don t solve any problems that weren t solved before, but yet you re convinced you have all the answers That seems to be a common theme with anyone whose education system stressed self-esteem over critical thinking. This reply just strikes me as willful ignorance 1 Really Rather than investigate and learn the truth, you just want to ridicule the answer I m not taking the bait Watch Brendan Eich s Fluent talks if you re interested in actually learning something 2 I know what types and type inference are, and I know the benefits of static types I ve been in this game since before JavaScript was invented TypeScript is a superset of JavaScript that compiles to JS allows for sophisticated static analysis It s structural type system is better than the type system Java had back when I was coding in Java, and it s much better as in more reliable and flexible than C and C 3 encapsulation, specialization via inheritance or prototyping , polymorphism, and externalizing dependencies via IoC - these are all forms of modularity, and JavaScript modules provide viable alternatives to all of them - and in the case of class inheritance, it s far superior See 4 your customers are waiting for the callback Fortunately, that s where the performance I talked about in point 1 shines JS provides efficient utilization of IO resources In fact, dealing with IO bottlenecks is the entire reason that Node was invented I ve ported several large production projects from PHP and Ruby to Node, and seen dramatic reductions in response times, both average response times and response time ranges - and since a typical Node app utilizes a small fraction of the memory required for C applications, your customer IO competes less with the RAM paging you might experience with a compiled C application 5 you say that like that sa good thing I ve seen objectively measurable increases in team velocity ranging from 40 - 60 improvements Believe it or not, it sa fact, and being more able to adapt to changing needs and experiment more particularly in the UI layer delivers very real business value Why do you think so many enterprise organizations are adopting Node It s not because some dev prefers JS It s because they ran the tests themselves and figured out it sa huge win Obviously you ve never heard of Mono, the cross platform that compiles and runs on every major OS Yeah, I have - what I haven t heard of is Mono delivering anywhere near the value that Node delivers in enterprise production Got a good article on that Cause a quick Google search isn t turning up much Check out this awesome result in the top 3 of the SERP but a quick Google search for Enterprise delivers quite a bit Here are the top 3 search results I see There s really no contest here.1, yes, I m mocking your evidently accidental claim that JavaScript makes electrons run faster, or even as fast as native, because it s patent nonsense Not only is that impossible, it ignores one of acknowledged weaknesses It sucks on compute intensive operations, because it s single threaded, which means compute intensive operations block execution duh 2 Your knowledge of Java does not qualify you to understand what a competent type system is Java s generics are a largely useless, johnny come lately me-too feature when compared against to C generics because they suffer from run-time erasure, in other words , the generic type safety and reflection only works at compile time, because at run time, everything is cast to an object So when you are going on about static analysis, you are effectively trying to claim it s as good as compile time run time type reflection, which is very far from the truth 3 Meh Chopping up everything into discrete functions is a form of modularity too, but it s vastly inferior to SOLID, which was my point in the first place And while prototype based inheritance is interesting, it s hardly better than real inheritance, which permits far more flexible arrangements 4 I don t see how it s impressive to speed up a Ruby app, or refactor some craptastic PHP into something faster Your memory overhead claims are equally baseless I can run on a watch or on an arduino device I can write that runs very well on an under-powered phone Look at the memory chrome consumes for an SPA, or try to run a complex javascript app on a tablet, and then tell me how lightweight JavaScript is 5 The lack of a proper separation of concerns which is the cause of most maintainability problems is the number one issue I encounter at enterprise scaled customers, and an impressive team velocity is always how they got there Why do I think a number of organizations are choosing node Because typically a mediocre, over-sized team of moderate competence fd up the previously shiny new thing that was supposed to solve all their problems, so they want to believe the hype that the problem is not them, but their previous technology choices.1 I think you misunderstood my meaning JS runs 1-2x SLOWER than native -- much better perf than any other dynamic language I know of It s fast enough to run AAA game engines like Unreal Engine and Unity in stunning quality at 60 fps 2 I actually think that a good native type tool would be a good addition to JavaScript, but only if they re user-definable structural types That said, JavaScript does support static analysis via type inference, and there are a number of ways to provide type hints for dev tools In addition , JavaScript also has an impressive array of runtime analysis tools 3 hardly better than real inheritance, which permits far more flexible arrangements Wrong 4 My apologies I was not aware of JavaScript also runs as-is on low-powered devices including Arduino, Tessel, and a number of others Node works great on most of them If that s not small enough, you can create a custom Node compile, drop features, even swap out the V8 engine for a different JS engine if you need to You can also restrict yourself to using tiny JS libraries of which there are many on npm to keep your codebase compact 5 they want to believe the hype that the problem is not them, but their previous technology choices That might explain an experiment or two, but the Node takeover is much more than that We re rapidly replacing apps in a variety of languages with Node Having worked at a fortune 500 during the transition to Node, I can tell you our justifications We did experimental ports to Node, found 1 that the app was faster and more reliable, delivering huge wins in both average response time, and the number of requests we could serve with the same machine, and 2 The developers were more productive for a variety of reasons, including the fact that JavaScript specialists could more easily work on both sides of the stack without context switching, and a lot of code could be shared in both the server and the client Those advantages have real, measurable influences on the company s bottom line That s why Node is taking over at both startups and enterprise companies. especially with edge it is really handy. Thanks Tamisalv I was looking for quick reference read for understanding and why projects might use it Reading this gave me a better understanding of advantages of this this technology and also when one might use it Cheers. After over 20 years of stateless - web based on the stateless request-response paradigm, we finally have web applications with real-time, two-way connections As a result we have webpages which take longer to load nowadays when we have Internet speeds in the order of megabytes per second, than back in the day when our speeds were in the order of bytes per second but our webpages were plain simple HTML Nowadays we have webpages which load halfway and then stop, which crash at the slightest network error ie dynamic IP address reassigning, or a momentary lapse in the WiFi signal forcing you to reload the whole page, whereas browsers are designed to gracefully handle those errors or resume once the network connection is restored, buggy Javascript scripts don t handle errors as well. I only have 1 question here with your statement It s structural type system is better than the type system Java had back when I was coding in Java, and it s much better as in more reliable and flexible than C and CI can not take that How can you examplify Some Facts with obviously answer in no - Why did Node inventor used V8 engine which was made in C to power node, if the js type system was so flexible and much better - Can nodejs decode vp8 codec video by itself as efficiently as CC - Could you build nodejs on top of pure javascript instead of C - Is there any such thing as pure javascript You really have to understand my friend that it is a type system that can take advantage of underlying hardware and makes your program efficient at CPU and memory Strongly typed C can solve any problem , even build node js Node shines at non-blocking io and that is about it, it can not do anything else Yes you can chop-off node code and make it work on micro devices but will it be efficient and make sense Can you make product like node where you have to code in C , yes you can but it would not make sense as power of CC in not in web, its optimizations and hardware It not like non-blocking IO is something new, we have had that in many technologies including java Net, basic, python and perl, this is very old The only reason why this thing is in limelight is it has enabled millions of frontend javascript developers, who do not understand pointers and bash about C , to write server code, which is simply overwhelming, that s why the buzz And about Node in particular are actually very well suited to handle distributed computation , why on earth one would write such a statement Node is not made for computation it can not compute as efficiently as CC Java Period With all due respect, lets not bring C in picture here, there is simply no practical comparison at all, or it will be very touchy. You may be interested in this. Actually, Javascript in the V8 server engine is QUITE fast The statement that Javascript is not fast is outdated You combine Node with Chrome and you get a very fast environment If you understand how Node works, it has an event loop that processes all code that is ready to run So, you call a function that has a blocking database call inside and a callback when finished, it allows the the function to be called, which returns immediately allowing you to get on with other things while the database call is being processed So you aren t hurry-up and waiting as you suppose You get on with other things, and once the database call finishes, execution will continue to the callback which is invoked after the database call returns So, you get the same basic abilities as a multi-threaded environment without all the extra overhead incurred by thread-state swapping Because you don t get time slicing you have to be careful that no piece of code takes too long to run, and if it does, you just break it up using packages like async I come from a long C, C , Delphi, Java background, having mastered the multi-threaded paradigm, and I can state assuredly that the Node single-threaded async paradigm is super cool, fast, and highly scalable IF YOU KNOW WHAT YOU RE DOING But that s the same for any of the other technologies as well None of these technologies are for neophytes. A complex application is precisely where well tailored Domain objects and properly decoupled subsystems are most necessary If you are spending all your time trying to get the ORM to work you should either learn that ORM better or get another ORM I would assume the former goes without saying so if you are still fighting your ORM it s time to choose one that just works. Excepting your last comment that these technologies are not for neophytes, I think you are ignoring the last two paragraphs you were responding to Even the founder of says to avoid compute intensive operations Yes, V8 speeds up javascript, but that doesn t solve the problem of a compute intensive operation or IO dependent operations blocking a single thread You then respond that is non-blocking and therefore it can be awaited Great, I got that, sure, but what are you waiting on Some code that isn t written in apparently, so much for the claimed benefit of one true language to rule them all , because your single threaded process is happily moved on to something else until the callback So, works great just as long as you can rely on other processes handling the workload that is blocking like waiting for IO , or another instance of single threaded that will if written correctly undoubtable kick the can down the road to yet another process And that s the issue there are a limited subset of stuff done in programs that can be executed in parallel out of order, and or doesn t rely on blocking operations Multi-threading is more complicated and has some overhead every time there is a context switch, but it means that more cores can be thrown at parallelizable units of work, and even discrete operations can be handled by the different threads In a solves everything world, you are either relying on something not written in or waiting for your single threaded application to finish up all the stuff that must be done, one way or another. You know what You seem to just like spouting on about something you are clearly not qualified to speak about You obviously have never built anything serious in Well, I have, and I can tell you that it works great if you actually program it correctly That means you use things like job queues, you use the clustering that Node provides, you make sure you do everything with callbacks and promises, you use async and setImmediate to properly share the processor between code that is waiting and code can now execute, you make sure UI code has priority over CPU intensive code, etc For example, I wrote an async heap sort algorithm that works great, sorting massive lists while not blocking for any appreciable amount of time I also have a 5000 line heuristic algorithm that is quite complex that I split up so that the main loops are executed using async constructs I then have these executed from a job queue called Kue that allows for efficient use of all cores, no threads, great UI response time, and complex calculation jobs being executed in the background using all available processor power This is ALL done in javascript with excellent performance in both CPU intensive tasks and response to front-end data requests In other words mate, the UI is super responsive, and the background processing complex heuristic calculation performed quickly and very responsively This is all done with a single language for both backend and front end, which is a huge deal when it comes to system architecture. Why are they not for neophytes Is it alcoholic. I agree Most times that I think an ORM is inadequate for complex queries, I write out raw SQL, later to find out the ORM has an app for that I like using an ORM as much as possible, but I won t spend too much time making it work for me, otherwise, as M said, I ll find another ORM. Sounds like the words from a Michael I know I agree with your last statement each technology has it place But why do you assume all Node developers are front-end developers with no back-end knowledge Why is it NOT possible for these developers to make a scalable solution Like or not Node is being used in Enterprise today and will continue to be adopted. Javascript is a poor choice of language for enterprise complex development It is messy, difficult to read, difficult to organise, doesn t support an entire raft of OO paradigms that save a lot of code repetition and provide readable abstraction, predominantly gives run time errors, no AOP, no by convention, no reflection, no generics templates, no precision of scope, no rich low level processing, and it is not type safe We are stuck with it in the browser, and frankly it is only inertia and legacy support that means it is still used there In all rights it should have gone the way of the dinosaurs 10 years ago The main driver to move away from scripting languages was that they were a maintenance nightmare and led to ball of mud applications that had constant bugs that couldn t be tracked It has only been a short 10 years since we breathed a huge sigh of relief when serious development moved off of scripting languages and here we are doing it again unwilling to learn from the past, convinced that this is new and cutting edge , rather than just old, tired and regurgitated It will end up the same way as it did last time, being talked about with disgust like classic asp and perl cgi I can only conclude the developers championing it now were just not around to see the fallout of this last time around Every new generation of developer is convinced they have discovered the truth , those of us who have seen this cycle of pain just have to sit back and shake our heads in disbelief Unfortunately you can t teach experience, it is something you have to learn the hard way Sure if you are an amateur and know nothing else then by all means, but anyone trying to do a professional job needs to leave this alone and stop making populist technology choices without considering the outcomes If you can t evaluate the long term limitations of a technology for yourself you shouldn t be working in development Developers need to stop being so childish, acting like a bunch of deluded fan boys, this is a serious business, not a game. OMG Eric Are you for real Do you even know how Nodejs works Did you even try to look at backbone of Nodejs Just download yourself a source-code and checkout IT IS IN PLAIN CC is C lib libuv is another and single most important C library in nodejs backbone which makes nodejs async, event driven and non blocking Javascript by itself is body without a soul and life JAVASCRIPT is just a script that you use to script your logic One day if smeoene ports lua with this libs, he will not need Javascript to code same for python etc But the basic fact remains the same IT IS C code that makes what nodejs is, not that javascript is too fast in fact javascript is slowest in all of the scripting language So don t flatter yourself in believing that just java-script is great and other things are shit And do not insult CC if you have no knowledge of it So, again, i urge you to take back your words Javascript type system is better then C Javascript has no type system and if you still believe that it has one, you are in a very wrong field, go build some scaffolding Also, these companies are not choosing nodejs for the reason you mentioned This is possible in almost all languages The reason why companies are choosing nodejs is that, they get ready made javascript coders, which are in millions and can not do c java code, to do server side because it is cheaper Another reason - its ecosystem Yet another reason - Its lot easier to conduct load tests in nodejs than other scripts The link you mentioned is work that is intended to be started Why do not you suggest them that please write this web-assembly compiler in nodejs rather than cc assembly because according to you that is superior C Mon man, how can you compare Nodejs A technology with a C language they are not in the same league C makes node possible, its not visa versa. The main driver to move away from scripting languages was that they were a maintenance nightmare and led to ball of mud applications -- could you clarify what you mean by scripting languages, and what replacements serious developers migrated to over the past ten years I was pleased to see a reference to Django in the article and have not run across maintainability issues caused by the use of Python, SQL, or ORMs in general On the contrary, Python is my go-to language precisely for its maintainability Your criticisms of js are spot on, but I can t see how they apply across the entire universe of scripting languages. Well I define scripting languages as runtime compilation languages, but there is a lot of overlap these days I prefer the reassurance of compile time verification of at least coding accuracy but that is not the only factor The depth of invasion into the inner workings of the compiler that tend to be exposed by compiled languages these days allow for a whole range of design constructs and patterns that allow programming to be more intelligent , I just don t find this level of sophistication in the scripting languages I have used It is a severe limitation for serious enterprise development ORMs are an ugly approach to data access on relational databases, but you would probably have to be a database developer to realise why Data design and Program design have different constraints , ORMs do either an injustice or have to be modified so much that they provide no productivity There are many issues such as security, isolation, atomic operations that ORMs break, and remember a database is a living system and may require changes in between code releases as a matter of course ORMs are a blunt tool if you want real performance from your database and want high concurrency without locking Its a detailed subject I could probably write a book on it, so sorry if this isn t conclusive enough for you Can t say much about Python other than I have heard good things in general I m the other end of the market on I crucify the open source guys next door in productivity and my defect level is about 1 of theirs I think you need a large system before it makes significant differences, as you need to invest in framework and substrate to get the main benefits back, its mass coding that is the enemy here When you have over a 100,000 code files you need a higher level of maintainability as it is simply beyond human capability to do it file by file and certainly beyond maintenance budgets By making core services that consume code as content you can achieve a high level of quality while keeping everything granular and ensuring release are small and targeted rather than entire system drops Each to their own, but if you are an IT pro you must have seen the millions of script based systems festering away in businesses because no one can find anything or understand how it works It s such a common complaint I should think it doesn t need justifying. PSI think serious developers have migrated to either Java, C or back to C along with their associated web techs etc I wasn t really intending to be derogatory but these three probably account for 90 of all commercial development atm C wins out on the commercial front for me solely on Microsoft s considerable ongoing investment and new found modernist approach C is not very productive and Java is really starting to look a little dated Still I work in all three and they get the job done, each have their place. PPS Python is my go-to language precisely for its maintainability What do you consider maintainability It is often not what people think it is or is not as simple as they think It encompasses the cost of change and that is the primary cost on the business for a living project Example I have a service with 1000 public methods and the business asks me to de-prioritise all calls that take over 2 seconds If I have to modify any of the code in those 1000 calls then my code has seriously poor maintainability What I should be making is one code change in my service substrate pipeline I should not even be modifying the substrate I should be probably writing a statistics module and a de-prioritise module for that substrate loaded in a separate dll that can be loaded dynamically Now my testing is isolated to just this dll reverse harness testing and when ready for release I can add this dll and maybe make one small config change, that s it, no regression testing and no risk to existing code, so no production bugs in the service methods So many typical code bases would require all 1000 methods to be altered or at least marked for an AOP operation Enterprise design requires upfront anticipation of future crazy business requests I find with most scripting languages and even with Java that finding insertion angles later on is nearly impossible Even if I have a complete mare in CI can emit the code directly into the methods using reflection, I have never seen this level of access on a scripting language and even if it was there it would be dangerous code to emit into runtime compiled operations because I am literally changing the operations content so I would need to test the result of each This is just one example I could probably come up with 100s I ma technical architect framework and substrate so it is my place to save my devs from backing themselves into a corner If I do a good job I can reduce the coding and testing effort to 1 of a mass coded system There is a whole other level of development that most devs will never see or appreciate, this means they are never equipped to make the most appropriate technology choices. Interesting article, I ve got quite a bit of experience in other realms but I m somewhat new to There sa few things I d like to clear up Flash was always async as well, it merely emulated threads much like it sounds like node does by using an event queue However, I believe it is technical ignorance to claim that trusting thread management to a 3rd or 4th generation language would be better than trusting a well-tuned JRE or operating system optimized for it s multi-core chipset How exactly do you think threads work in the lower levels anyway It isn t some magic , the only way to get true simultaneous code execution is via multiple processors, something you simply can t accomplish with a single thread It s also a mistake to say that a new event does not add memory or clock cycles taken to a stack just because said events are managed by an interpreted scripting language rather than optimized, compiled CI d bet my lunch that a well-written multi-threaded web application written in C or C will blow away any app performance-wise, and that s even without getting into servers and their current multi-core processor architecture If you ve got a quad or 8-core server running a single node thread you re only firing on one piston quite ironic that Google calls their engine V8 when considering such a fact Another thing to realize is that while Flash or even Java applets ran in their own runtimes, so does node -- it s just hidden to the user That is nothing more than good perhaps hostile business moves on Google s part Lets be honest here, if all browsers came with Flash automatically installed on them, and Apple actually supported Flash on their mobile devices, node probably wouldn t even exist today I have other concerns about security What kind of protection does it have against cross-site scripting and other attacks Earlier today I stumbled across a TOR Bittorrent client that ran in my browser window, and after opening it my computer wouldn t shut down nicely it scares me to think what it could have been seeding No warnings about security or what types of connections my browser window was opening up , just went along with it s P2P business the hacker side of me could have a real hay day with those kind of features I doubt that kind of stuff has been tested much either which means there sa lot of room for bugs, and where there sa lot of room for bugs there sa lot of room for vulnerabilities But hey, at least your entire stack is all in the same language Means you can hire less experienced developers for less money, right. Good Article for Node JS, you can learn Node JS online in or send a email. You could remove all the pitfalls of JS by using the its superset aka TypeScript. Tldr Use node for IO-heavy processing and delegating CPU-intensive processing to a cluster of specialized worker nodes ex database, media processing, etc This isn t exactly new information I covered this topic back in 12 Ideally, the and API servers should be mostly stateless excl session management and disposable They re just a functional pipeline that translates the raw data into consumable representations That way, the servers are easy to provision destroy dynamically to meet the spikey nature of demand I m not sure why so many of the commenters are vehemently arguing in favor of multi-purpose vertically-scalable server architectures By nature, vertical scaling will always have an upper limit predicated by hardware capacity No matter how efficient the code is The writing is on the wall You can spend a fortune on hardware and lose sleep questioning the validity of your risk assessment aka WAG At the end of the day, bare metal is a fixed asset Best case, it meets expected demand and justifies the cost Worst case, it either costs more than it s worth or lacks the capacity to meet demand Alternatively, you can embrace distributive computing and automate the infrastructure to grow contract relative to demand For the people fighting religious wars over which language is best, node C java Who cares All 3 allow functional-style programming All 3, support async processing natively or through extensions All 3 can be managed via provisioning All 3 are perfectly valid for building distributive infrastructure Choosing which one to use depends on the quality of the tools, whether or not it will be used to extend existing infrastructure, and the perception of the client Build whatever you re good at building If you re really good build whatever is easiest to implement, support, and generate the most profit or save the most on cost BTW, kudos to the author It s nice to see somebody do a comprehensive and mostly objective writeup on this topic. Yes, both languages support horizontal scaling with asynchronous message management infrastructure CQRS is nothing but an API implementation pattern CRUD is the typical use case as it should be but Node doesn t automagically scaffold 1 1 mappings between DB and CRUD see rails laravel django for that Node isn ta framework at all, it s just a server You can leverage frameworks ex Express to more easily leverage the full power of Node but you still have to fine-tune your routes to define a fully functional API Net Reactive Extensions have been ported to JS In fact, even LINQ has been ported to JS yes, seriously ORMs are only an issue because they require an additional layer of abstraction from the underlying data If read when the data models need to change to adapt to business demands, both the ORM and the database schema will need to be updated and tested to reflect the changes Which is not really a big deal if there sa good update strategy in place As for the rest of your comment, you d do well if you stepped out of your comfort zone once in a while to see how JS development really works 1 JS classes are currently supported now via ES6 also, available client - side via polyfills Prototypes really aren t much different than classes in terms of encapsulation except they re a lot more flexible Compile-time static type checking is even supported via TypeScript Dart if that s what floats your boat, it s just not the default 2 TDD BDD isn ta feature exclusive to statically typed languages There are a lot of great testing frameworks available in JS both server client-side Choose your flavor, unit testing Mocha , behavior driven unit testing Chai , api testing SuperTest , and continuous integration testing TravisCI, and many others are all used extensively throughout the community JSUnit the JS equivalent of JUnit NUnit is even available if you miss unit testing in If anything, testing is a basic requirement of any non-trivial JS app that goes into production because you don t have a compile-time type checker to hold your hand 3 Complex workflow Seriously So, you ve never heard of NPM scripting, grunt, gulp Automating any-and-everything in JS is pretty easy Style enforcement, linting, documentation generation, scaffolding, one-click - deployment, language transpilation, bundling, distribution building, package dependency management, release management, etc 4 cringe if you rely on the compile-time static type checking system alone to validate user input, you re doing it wrong Building a data layer in any language requires constraints above-and-beyond what the default types provide So, either way you ll have to extend your data models with custom validation checks The cool part about handling validation in JS is you can use the same routines to check user input on both the client server-side Less duplication of effort FTW Contrary to what you think Javascript really is a one size fits all approach if you prefer to use it as such Seriously, you can even compile CC directly to javascript using Does that mean you have to use it Of course not Any developer with a speck of sense wouldn t fault you for choosing C , it sa great language I have experience writing code in many languages, including building non-trivial desktop applications in C Given a choice, I d prefer to use Javascript The mix of, looser constraints and functional imperative prototype styles allow for a level of creativity I haven t experienced in any other language The tools are great, the module system is amazing, and the language itself is getting substantially better with each update. Upload Files All the IO operations is handled by is using multiple threads internally it s the programming interface to that IO functionality that s single threaded, event-based, and asynchronous Libuv uses a thread-pool to handle IO operations files, sockets, etc in an asynchronous manner Where most languages block by default during CPU-heavy IO operations, Node doesn t It simply fires an event when the IO operation completes on the worker thread Active Directory. The distinction is that Node is async by default So, the number of developers doing async programming in other languages are the minority so they re not as well represented I can t come up with any good reason to use it on the server side in favor to other available languages Not gonna lie, using Node at first was Challenging to say the least Getting used to async-by-default is not an easy transition The nice part Node is, the primary focus of the platform is building servers clients so the ecosystem has a lot of powerful tools to do anything dealing with web development have better standard libraries, tools and resources I m not sure what gave you that impression It doesn t use the monolithic-everything-and-the-kitchen-sink base class library approach The core itself is very small but that sa benefit as it s much lighter to deploy It also includes a very powerful, full-featured package manager by default so you re expected to add the dependencies your project needs NPM Node Package Manager has over 200K packages and counting Since the majority of the modules are developed independently from the core, they iterate and improve much faster than the equivalent core libraries in other languages Dependencies are managed locally on a per-project basis in the file Typically, it s bad form for a module author to require that their package be installed globally Installing packages locally prevents version conflicts at the global level and guarantees that -- when you install a package -- everything required to use the module is included It may seem inefficient at first glance because many dependencies may have copies of the same sub-dependencies or sub-subdeps, etc but compared to the cost of including a massive standard library, the storage space is insignificant The workflow to setup a project is - clone the source - run npm install NPM will automatically download and install all of the dependencies incl sub-deps, sub-sub - deps, etc Since the dependencies and their specific versions are explicitly defined in the config, you don t need to check them into source control In addition, with ES6 incl the new ES6-module-loader about to be released, a new JSPM Javascript Package Manager has been created to manage client-side javascript dependencies Module imports in the browser have finally been formalized in the language spec, so Bower and the variety of module-loading pseudo-standards ex AMD, CommonJS, UMD will go away. As said above modern OO languages have a vast array of options to formalize and control your code and solutions that are lacking in scripting languages That s just the plain truth, no amount of griping is going to change that My point is there are a lot of developers choosing technology by popularity rather than suitability, that s what makes them fan boys Right tool for the right job, applies in every trade apart from software development apparently But that is probably because most developers aren t true Tradesman , more glorified DIY ers The industry is full of amateurs who don t even know enough to know that they know nothing They think because they can write an if statement and a while loop they are pros Techno-weenies. System level IO operations such as files, sockets in Node are handled by libuv which does use a background thread pool The difference is, the main thread can fire and forget the task to a background thread and the background thread will notify the main thread via firing an event when the operation is completed Even with background thread processing, doing lots of IO operations doesn t scale very well For long-running CPU-heavy tasks ex image movie encoding offloading the tasks to worker nodes is still preferable In most languages, IO operations are handled in a synchronous manner so if they requests are made on the main thread, they ll block execution until completed The reason you don t see a noticeable pause in the UI when this happens is because the UI is asynchronous event-based and runs on a thread separate from the main context. There s nothing stopping you from exposing the API as a microservice WebKit just allows you to run a native JS client I may be wrong but from what I understand, unlike the browser a webkit client isn t as strictly sandboxed so you can make system calls ex to open save files without user input. I think you made my point for me, frothing unthinking, emotional nonsense, with very little in the way of fact, from a mind so fanatic about one thing it can t even see its failings You seem to have made a fair few assumptions about what I do and don t know, I have been doing Javascript for 20 years, I know its short comings, I can work effectively in probably 30 languages, I use what is appropriate, I never indicated otherwise You need to grow up or find a new industry to work in People like you are the problem with Software Development, no nothing nobodies who can t even make a case for a technology, let alone use one Please stay away from the keyboard and do the rest of us a favour. Do you use version control with a standard workflow ex Gitflow workflow where developers make changes on feature branches and code is peer reviewed before being merged I ve been messing around with trying to build an Angular2 website lately and the Angular2 project is still in early alpha so breaking changes are a regular albeit unfortunate occurrence All of the available examples online are pretty-much broken so I ve been monitoring the project development on Github The rate that the core developers are thrashing on the codebase is truly remarkable What s even more amazing is that every PR is unit tested and continuous integration tested well enough that every release is guaranteed to be fully functional as far as they ve implemented it so far. Following what Tracker1 is saying Linting is the equivalent of compile-time checking in JS I even use a Sublime extension that shows linter errors directly in the gutter of the editor as I m writing code If you want stricter checking you can add a style checker such as semistandard which guarantees code styling on a project-wide basis That means, spaces-not-tabs, indent 2 spaces , consistent functions, curly braces, etc Type checking is good for superficial bugs ex uninitialized variables, dead branches, invalid values but eventually you ll have to verify the code doesn t have logic bugs through unit testing, continuous integration testing, api testing. Node uses async event-based IO via libuv incl a thread pool reserved for IO requests The main thread absolutely does not block during IO operations It works the same way cluster would except it s built into Node Check out one of the presentations on libuv for more details. Performance wise, PayPal seems to think good things about Node For security, the cors module is pluggable to Express and can be used for all the usual CORS control stuff The helmet module -- also pluggable to Express -- exposes a small suite of features to protect against malicious users including additional cross site scripting protection I m not sure if I d call a Fullstack JS dev inexperienced Having a solid understanding of multiple domains in a development ecosystem that is constantly evolving is maddening ya know, 10 years of experience vs 1 year of experience 10 times. hasn t even been around for 10 years which is funny considering I have seen job postings actually asking for 10 years experience with it I understand that following evolving technology is a challenge, and after 20 years I can tell you that by the time you get completely comfortable with any full stack it will be less relevant because technology is always advancing Nothing will change that, it s just how things work However, you can t really have your cake and eat it too there Newer technology is less tested and therefore less secure, but older technology does not have as many features There s always a trade-off there Anybody who claims otherwise is selling you something. I am sold on if your application is into building high scalability networking applications , is the way to go in 2015 No wonder why so many startups and large corporations are adopting it C , Java, Ruby and Python havew their place in their respective domains New companies and products will be getting built on wide variety of languages I predict ROR adoption would still be high in coming years for building web applications simply because ROR developers are easily available and time to market is so small Excellent article though Tomislav. So true My job is the maintainance of legacy apps usually SQL Server dB s ms access or pop fronteds These were usually made by the grandson who is good with computers Kind of guy No foreign keys, but custom date time functions Your post is my sentiment exactly. I find Java very unproductive and very expensive for a lot of low level tedious work C is for programmers who can handle memory access pointers Most corporate programmers cannot Back in the day you had PL 1 and C for software engineers and COBOL for information technology programmers. thanks this is so helpful as i am going to make a heavy-computation enterprise application i think i ll try on other application for now, i ll use ruby on rails. When this article was written. Thanks for this article I think than the argument of same langage for front and dev is the worst I can liste or read Organized good coding with js is the more horrible things append in a team I work since last year on backend project and where this should be coded in some times with mature framework like django it took too much time understand hundreds bugs Where mongodb feels cool Never I realy thinks than nodejs is a big joke and not So cool The package manager give us some cool package to patch and hide the bad side of node but there is nothing to do about the callback hell Finally the code looks like a big sand box than i hatte to open a file for debug or add some lines of code So my conclusion is than for small app why not but for big and evolutive project not use nor nodejs and mongodb Regards. This is a fairly ill-informed comment as ES6 was alive and well as at a year ago Besides the OO from ES6, there is also TypeScript which adds even more enterprise-level OO to JavaScript Like is compiled, TypeScript may also be transpiled to Javascript NodeJS allows for pretty much of all this now with an even still better utilization of server resources and no OS lock-in Think cutting your infrastructure costs by 2000 because you really shouldn t need to scale too vertically or pay for that license per node Fintech companies like Paypal are happily doing great things with node as well so I highly doubt this comment of yours comes from a place of non-ignorance about what NodeJS eco-system truly offers the enterprising product. I really wanna be able to try out but it s such a pain in the effing ass to get something running Installing a simple app always turns in to a list of things you need to do, install shit globally which is NOT always possible , edit files, try to figure out what the damn devs mean in their scant instructions It quickly goes to shit if you do the slightest thing wrong If it s so great why hasn t anyone figured out a way to make simple installers with this thing. Ghost blogging platform. David M Tromholt. Yeah it would be nice with a date I assume they don t show it because they know how biased people are towards new information but it doesn t make much sense to hide it in an article about a fast growing technology. Hi Avinash, Can you please eloborate little more on your statement I am trying to understand more on this. Would node be a bad idea for something like then Would you need to do any image manipulation on a different server to prevent blocking. Hey Tomislav, Great article I wanted to know that if suppose I want to get external hardware output in my app, e g, scanner or e-signature if user is doing e-signature or getting scanned copy from scanner , then can i get directly in my app it will be like an api call as we do in Java. TypeScript is syntactic sugar wrapper on top of standard JavaScript and compiles into standard JavaScript It is invented to make the code maintainable and allows it to be used more like a real programming language Given that you have to use JS where appropriate it makes writing it more familiar to real programmers and makes it maintainable That said, anything JS and Node is appropriate for thin, lightweight web apps that need to be put together quickly and efficiently, for which things like JSP, Ruby etc are a bit of overkill Believing that one can not use the new magic Node for everything just because one guy can write front and back end is amateurish. Encapsulating a language with another language, which you have to translate will add overhead Also there are things that don t translate, just in real life translating between language, you loose something In this case you loose speed having to translate from one to the other , and optimization, because of reason one ORM s don t do it all In the beginning, I was for ORMs, then I dove deep into it and you end up with How do I do this , Oh you can t easily, you have to do 10 other queries , or you end up with stuff that just seems like it should work well, but you end up wrecking the performance ORMs are for simple Select blah blah from table where x y. Hey, is there a library tool you used to creste the graphics. Praveen kumar Pamani. Thank you for this article I would suggest this article if people want to know what is node and what can we do with nodejs.