From b34792a480031f8c4b0d911eae25ea7bc99f4928 Mon Sep 17 00:00:00 2001 From: Ryan Date: Wed, 13 May 2009 17:46:00 +0200 Subject: [PATCH] Add webpage. Very incomplete. --- node.html | 222 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 222 insertions(+) create mode 100644 node.html diff --git a/node.html b/node.html new file mode 100644 index 0000000..5cf2a85 --- /dev/null +++ b/node.html @@ -0,0 +1,222 @@ + + + + node.js + +
+
    +
  1. Motivation
    2. +
  2. Benchmarks
    3. +
  3. Download
    4. +
  4. Build
    5. +
  5. API +
      +
    1. Timers +
    2. File System +
    3. TCP +
    4. HTTP +
    5. Modules +
    +
    6. +
+
+
+ +

Node

+ +

Node is a purely evented I/O framework for V8 javascript. Its goal is to enable easy development of + highly concurrent, small footprint programs. For example, this is a + simple web server which responds with "Hello World" after waiting two + seconds: +

+node.http.server(function (msg) {
+  setTimeout(function () {
+    msg.sendHeader(200, [["Content-Type", "text/plain"]]);
+    msg.sendBody("Hello World");
+    msg.finish();
+  }, 2000);
+}).listen(8000, "localhost");
+
+ +

While one request is waiting the server will continue to accept and + serve other requests. This is accomplished without threads and is quite + efficient: handling hundreds of concurrent requests while using + little CPU or memory—see benchmarks. + The example might seem esoteric but similar behavior + is required to implement, for example, "comet" servers. + +

Node is free to download, use, and build upon.

+ +

Motivation

+ +
    +
  1. Evented programming makes sense +
      +
    1. difference between blocking/non-blocking design +
    2. latency figures +
    3. purely evented interfaces rule out a lot of stupidity +
    +
  2. Evented programs are more efficient +
      +
    1. pthread stack size +
    2. context switching benchmark +
    3. Apache vs. Nginx +
    4. event machine vs mongrel (neverblock) +
    +
  3. The appropriateness of Javascript +
      +
    1. No I/O +
    2. No Threads +
    3. Good compiler +
    4. Universality of the language +
    +
+ + Threads are a bad model. + +

+ I/O latency + 

+    l1 cache ~ 3
+    l2 cache ~ 14
+         ram ~ 250
+        disk ~ 41000000
+     network ~ 240000000
+
+ +

Javascript is without I/O. In the browser the DOM provides I/O, + but non-browser javascript interpreters have only non-standardized + functions to allow them print to console or access the network. + +

Javascript is without the concept of threads. + +

Contemporary computer infrastructure has two irreplaceable + languages: C and Javascript. C is the language of operating systems. + POSIX, the universal operating system API, is defined in C. So while you + can interface with operating systems in Java and Haskell, those + languages access must make system calls in C. Similarly, Javascript is + the language of the web operating system. In place of POSIX is the + DOM. You can wrap Javascript, you can compile to Javascript, but in the + end browsers must be interfaced with in Javascript. Portable low-level + systems tend to be written in C and portable web-level systems are + written in Javascript. + +

Evented vs Threaded Servers

+ +

There are many methods to write internet servers but they can + fundamentally be divided into two camps: evented and threaded; non-blocking + and blocking. A blocking server accepts a connection and launches a new + thread to handle the connection. Because the concurrency is handled by + the thread scheduler, a blocking server can make function calls which + preform full network requests. + + 

var response = db.execute("SELECT * FROM table");
+// do something
+ +

An evented server manages its concurrency itself. All connections + are handled in a single thread and callbacks are executed on certain + events: "socket 23 is has data to read", "socket 65's write buffer is + empty". An evented server executes small bits of code but never + blocks the process. In the evented world callbacks are used + instead of functions + +

db.execute("SELECT * FROM table", function (response) {
+  // do something
+});
+ + +

Benchmarks

+ +

Download

+ + +

Build

+ +
configure
+make
+make install
+ + +

Application Programming Interface

+ +

The node executable should be given an argument pointing to a + javascript file. + +

Timers

+ +

The timer API is the same as in the browser. The functions + setTimeout, setInterval, cancleTimeout, and cancleInterval + +

File System

+ +

TCP

+ +

HTTP

+ +

Modules

+ + -- 2.7.4