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|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta name="generator" content="AsciiDoc 8.4.5" />
<title>NODE(1)</title>
<link rel="stylesheet" href="./pipe.css" type="text/css" />
<link rel="stylesheet" href="./pipe-quirks.css" type="text/css" />
<script type="text/javascript">
/*<![CDATA[*/
window.onload = function(){generateToc(2)}
/*]]>*/
</script>
<script type="text/javascript" src="./toc.js"></script>
</head>
<body>
<div id="header">
<h1>NODE(1)</h1>
<span id="author">Ryan Dahl</span><br />
<span id="email"><tt><<a href="mailto:ry@tinyclouds.org">ry@tinyclouds.org</a>></tt></span><br />
<span id="revnumber">version 0.1.13,</span>
<span id="revdate">2009.09.30</span>
<div id="toc">
<div id="toctitle">Table of Contents</div>
<noscript><p><b>JavaScript must be enabled in your browser to display the table of contents.</b></p></noscript>
</div>
</div>
<h2 id="_name">NAME</h2>
<div class="sectionbody">
<div class="paragraph"><p>node - evented I/O for V8 javascript</p></div>
</div>
<h2 id="_synopsis">SYNOPSIS</h2>
<div class="sectionbody">
<div class="paragraph"><p>An example of a web server written with Node which responds with "Hello
World":</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>include("/utils.js");
include("/http.js");
createServer(function (request, response) {
response.sendHeader(200, {"Content-Type": "text/plain"});
response.sendBody("Hello World\n");
response.finish();
}).listen(8000);
puts("Server running at http://127.0.0.1:8000/");</tt></pre>
</div></div>
<div class="paragraph"><p>To run the server, put the code into a file called <tt>example.js</tt> and execute
it with the node program</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>> node example.js
Server running at http://127.0.0.1:8000/</tt></pre>
</div></div>
</div>
<h2 id="_api">API</h2>
<div class="sectionbody">
<div class="paragraph"><p>Node supports 3 string encodings. UTF-8 (<tt>"utf8"</tt>), ASCII (<tt>"ascii"</tt>), and
Binary (<tt>"binary"</tt>). <tt>"ascii"</tt> and <tt>"binary"</tt> only look at the first 8 bits
of the 16bit javascript string characters. Both are relatively fast—use
them if you can. <tt>"utf8"</tt> is slower and should be avoided when possible.</p></div>
<div class="paragraph"><p>Unless otherwise noted, functions are all asynchronous and do not block
execution.</p></div>
<h3 id="_helpers">Helpers</h3><div style="clear:left"></div>
<div class="paragraph"><p>These objects are available to all programs.</p></div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>node.cwd()</tt>
</dt>
<dd>
<p>
Returns the current working directory of the process.
</p>
</dd>
<dt class="hdlist1">
<tt>node.compile(source, scriptOrigin)</tt>
</dt>
<dd>
<p>
Just like <tt>eval()</tt> except that you can specify a <tt>scriptOrigin</tt> for better
error reporting.
</p>
</dd>
<dt class="hdlist1">
<tt>__filename</tt>
</dt>
<dd>
<p>
The filename of the script being executed.
</p>
</dd>
<dt class="hdlist1">
<tt>require(path)</tt>
</dt>
<dt class="hdlist1">
<tt>include(path)</tt>
</dt>
<dd>
<p>
See the modules section.
</p>
</dd>
<dt class="hdlist1">
<tt>node.libraryPaths</tt>
</dt>
<dd>
<p>
The search path for absolute path arguments to <tt>require()</tt> and <tt>include()</tt>.
</p>
</dd>
</dl></div>
<h3 id="_the_tt_process_tt_object">The <tt>process</tt> Object</h3><div style="clear:left"></div>
<div class="paragraph"><p><tt>process</tt> is the equivalent of <tt>window</tt> in browser-side javascript. It is
the global scope. <tt>process</tt> is an instance of <tt>node.EventEmitter</tt>.</p></div>
<div class="tableblock">
<table rules="all"
width="100%"
frame="border"
cellspacing="0" cellpadding="4">
<col width="7%" />
<col width="15%" />
<col width="76%" />
<thead>
<tr>
<th align="left" valign="top"> Event </th>
<th align="left" valign="top"> Parameters </th>
<th align="left" valign="top"> Notes</th>
</tr>
</thead>
<tbody>
<tr>
<td align="left" valign="top"><p class="table"><tt>"exit"</tt></p></td>
<td align="left" valign="top"><p class="table"><tt>code</tt></p></td>
<td align="left" valign="top"><p class="table">Made when the process exits.
A listener on this event should not try to perform
I/O since the process will forcibly exit in less
than microsecond. However, it is a good hook to
perform constant time checks of the module’s
state (like for unit tests).
<br />
The parameter <tt>code</tt> is the integer exit code
passed to <tt>process.exit()</tt>.</p></td>
</tr>
</tbody>
</table>
</div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>process.exit(code=0)</tt>
</dt>
<dd>
<p>
Ends the process with the specified code. By default it exits with the
success code 0.
</p>
</dd>
<dt class="hdlist1">
<tt>process.ARGV</tt>
</dt>
<dd>
<p>
An array containing the command line arguments.
</p>
</dd>
<dt class="hdlist1">
<tt>process.ENV</tt>
</dt>
<dd>
<p>
An object containing the user environment. See environ(7).
</p>
</dd>
</dl></div>
<h3 id="_utilities">Utilities</h3><div style="clear:left"></div>
<div class="paragraph"><p>These function are in <tt>"/utils.js"</tt>. Use <tt>require("/utils.js")</tt> to access them.</p></div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>puts(string)</tt>
</dt>
<dd>
<p>
Outputs the <tt>string</tt> and a trailing new-line to <tt>stdout</tt>.
</p>
</dd>
<dt class="hdlist1">
<tt>print(string)</tt>
</dt>
<dd>
<p>
Like <tt>puts()</tt> but without the trailing new-line.
</p>
</dd>
<dt class="hdlist1">
<tt>debug(string)</tt>
</dt>
<dd>
<p>
A synchronous output function. Will block the process and
output the string immediately to stdout.
</p>
</dd>
<dt class="hdlist1">
<tt>inspect(object)</tt>
</dt>
<dd>
<p>
Return a string representation of the <tt>object</tt>. (For debugging.)
</p>
</dd>
<dt class="hdlist1">
<tt>exec(command)</tt>
</dt>
<dd>
<p>
Executes the command as a child process, buffers the output and returns it
in a promise callback.
</p>
<div class="listingblock">
<div class="content">
<pre><tt>include("/utils.js");
exec("ls /").addCallback(function (stdout, stderr) {
puts(stdout);
});</tt></pre>
</div></div>
<div class="ulist"><ul>
<li>
<p>
on success: stdout buffer, stderr buffer
</p>
</li>
<li>
<p>
on error: exit code, stdout buffer, stderr buffer
</p>
</li>
</ul></div>
</dd>
</dl></div>
<h3 id="_events">Events</h3><div style="clear:left"></div>
<div class="paragraph"><p>Many objects in Node emit events: a TCP server emits an event each time
there is a connection, a child process emits an event when it exits. All
objects which emit events are are instances of <tt>node.EventEmitter</tt>.</p></div>
<div class="paragraph"><p>Events are represented by a camel-cased string. Here are some examples:
<tt>"connection"</tt>, <tt>"receive"</tt>, <tt>"messageBegin"</tt>.</p></div>
<div class="paragraph"><p>Functions can be then be attached to objects, to be executed when an event
is emitted. These functions are called <em>listeners</em>.</p></div>
<div class="paragraph"><p>Some asynchronous file operations return an <tt>EventEmitter</tt> called a
<em>promise</em>. A promise emits just a single event when the operation is
complete.</p></div>
<h4 id="_tt_node_eventemitter_tt"><tt>node.EventEmitter</tt></h4>
<div class="paragraph"><p>All EventEmitters emit the event <tt>"newListener"</tt> when new listeners are
added.</p></div>
<div class="tableblock">
<table rules="all"
width="100%"
frame="border"
cellspacing="0" cellpadding="4">
<col width="7%" />
<col width="15%" />
<col width="76%" />
<thead>
<tr>
<th align="left" valign="top"> Event </th>
<th align="left" valign="top"> Parameters </th>
<th align="left" valign="top"> Notes</th>
</tr>
</thead>
<tbody>
<tr>
<td align="left" valign="top"><p class="table"><tt>"newListener"</tt></p></td>
<td align="left" valign="top"><p class="table"><tt>event, listener</tt></p></td>
<td align="left" valign="top"><p class="table">This event is made
any time someone adds
a new listener.</p></td>
</tr>
</tbody>
</table>
</div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>emitter.addListener(event, listener)</tt>
</dt>
<dd>
<p>
Adds a listener to the end of the listeners array for the specified event.
</p>
<div class="listingblock">
<div class="content">
<pre><tt>server.addListener("connection", function (socket) {
puts("someone connected!");
});</tt></pre>
</div></div>
</dd>
<dt class="hdlist1">
<tt>emitter.listeners(event)</tt>
</dt>
<dd>
<p>
Returns an array of listeners for the specified event. This array can be
manipulated, e.g. to remove listeners.
</p>
</dd>
<dt class="hdlist1">
<tt>emitter.emit(event, arg1, arg2, …)</tt>
</dt>
<dd>
<p>
Execute each of the listeners in order with the supplied arguments.
</p>
</dd>
</dl></div>
<h4 id="_tt_node_promise_tt"><tt>node.Promise</tt></h4>
<div class="paragraph"><p><tt>node.Promise</tt> inherits from <tt>node.eventEmitter</tt>. A promise emits one of two
events: <tt>"success"</tt> or <tt>"error"</tt>. After emitting its event, it will not
emit anymore events.</p></div>
<div class="tableblock">
<table rules="all"
width="100%"
frame="border"
cellspacing="0" cellpadding="4">
<col width="7%" />
<col width="15%" />
<col width="76%" />
<thead>
<tr>
<th align="left" valign="top"> Event </th>
<th align="left" valign="top"> Parameters </th>
<th align="left" valign="top"> Notes</th>
</tr>
</thead>
<tbody>
<tr>
<td align="left" valign="top"><p class="table"><tt>"success"</tt></p></td>
<td align="left" valign="top"><p class="table">(depends)</p></td>
<td align="left" valign="top"><p class="table"></p></td>
</tr>
<tr>
<td align="left" valign="top"><p class="table"><tt>"error"</tt></p></td>
<td align="left" valign="top"><p class="table">(depends)</p></td>
<td align="left" valign="top"><p class="table"></p></td>
</tr>
</tbody>
</table>
</div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>promise.addCallback(listener)</tt>
</dt>
<dd>
<p>
Adds a listener for the <tt>"success"</tt> event. Returns the same promise object.
</p>
</dd>
<dt class="hdlist1">
<tt>promise.addErrback(listener)</tt>
</dt>
<dd>
<p>
Adds a listener for the <tt>"error"</tt> event. Returns the same promise object.
</p>
</dd>
<dt class="hdlist1">
<tt>promise.emitSuccess(arg1, arg2, …)</tt>
</dt>
<dd>
<p>
If you created the promise (by doing <tt>new node.Promise()</tt>) then call
<tt>emitSuccess</tt> to emit the <tt>"success"</tt> event with the given arguments.
</p>
<div class="paragraph"><p>(<tt>promise.emit("success", arg1, arg2, …)</tt> should also work, but doesn’t at
the moment due to a bug; use <tt>emitSuccess</tt> instead.)</p></div>
</dd>
<dt class="hdlist1">
<tt>promise.emitError(arg1, arg2, …)</tt>
</dt>
<dd>
<p>
Emits the <tt>"error"</tt> event.
</p>
</dd>
<dt class="hdlist1">
<tt>promise.wait()</tt>
</dt>
<dd>
<p>
Blocks futher execution until the promise emits a success or error event.
Events setup before the call to <tt>promise.wait()</tt> was made may still be
emitted and executed while <tt>promise.wait()</tt> is blocking.
</p>
<div class="paragraph"><p>If there was a single argument to the <tt>"success"</tt> event then it is returned.
If there were multiple arguments to <tt>"success"</tt> then they are returned as an
array.</p></div>
<div class="paragraph"><p>If <tt>"error"</tt> was emitted instead, <tt>wait()</tt> throws an error.</p></div>
<div class="paragraph"><p><strong>IMPORTANT</strong> <tt>promise.wait()</tt> is not a true fiber/coroutine. If any other
promises are created and made to wait while the first promise waits, the
first promise’s wait will not return until all others return. The benefit of
this is a simple implementation and the event loop does not get blocked.
Disadvantage is the possibility of situations where the promise stack grows
infinitely large because promises keep getting created and keep being told
to wait(). Use <tt>promise.wait()</tt> sparingly—probably best used only during
program setup, not during busy server activity.</p></div>
</dd>
</dl></div>
<h3 id="_standard_i_o">Standard I/O</h3><div style="clear:left"></div>
<div class="paragraph"><p>Standard I/O is handled through a special object <tt>node.stdio</tt>. stdout and
stdin are fully non-blocking (even when piping to files). stderr is
synchronous.</p></div>
<div class="tableblock">
<table rules="all"
width="100%"
frame="border"
cellspacing="0" cellpadding="4">
<col width="7%" />
<col width="15%" />
<col width="76%" />
<thead>
<tr>
<th align="left" valign="top"> Event </th>
<th align="left" valign="top"> Parameters </th>
<th align="left" valign="top"> Notes</th>
</tr>
</thead>
<tbody>
<tr>
<td align="left" valign="top"><p class="table"><tt>"data"</tt></p></td>
<td align="left" valign="top"><p class="table"><tt>data</tt></p></td>
<td align="left" valign="top"><p class="table">Made when stdin has received a chunk of data.
Depending on the encoding that stdin was opened
with, <tt>data</tt> will be a string. This event will
only be emited after <tt>node.stdio.open()</tt> has
been called.</p></td>
</tr>
<tr>
<td align="left" valign="top"><p class="table"><tt>"close"</tt></p></td>
<td align="left" valign="top"><p class="table"></p></td>
<td align="left" valign="top"><p class="table">Made when stdin has been closed.</p></td>
</tr>
</tbody>
</table>
</div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>node.stdio.open(encoding="utf8")</tt>
</dt>
<dd>
<p>
Open stdin. The program will not exit until <tt>node.stdio.close()</tt> has been
called or the <tt>"close"</tt> event has been emitted.
</p>
</dd>
<dt class="hdlist1">
<tt>node.stdio.write(data)</tt>
</dt>
<dd>
<p>
Write data to stdout.
</p>
</dd>
<dt class="hdlist1">
<tt>node.stdio.writeError(data)</tt>
</dt>
<dd>
<p>
Write data to stderr. Synchronous.
</p>
</dd>
<dt class="hdlist1">
<tt>node.stdio.close()</tt>
</dt>
<dd>
<p>
Close stdin.
</p>
</dd>
</dl></div>
<h3 id="_modules">Modules</h3><div style="clear:left"></div>
<div class="paragraph"><p>Node has a simple module loading system. In Node, files and modules are in
one-to-one correspondence. As an example, <tt>foo.js</tt> loads the module
<tt>circle.js</tt>.</p></div>
<div class="paragraph"><p>The contents of <tt>foo.js</tt>:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>var circle = require("circle.js");
include("/utils.js");
puts("The area of a circle of radius 4 is " + circle.area(4));</tt></pre>
</div></div>
<div class="paragraph"><p>The contents of <tt>circle.js</tt>:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>var PI = 3.14;
exports.area = function (r) {
return PI * r * r;
};
exports.circumference = function (r) {
return 2 * PI * r;
};</tt></pre>
</div></div>
<div class="paragraph"><p>The module <tt>circle.js</tt> has exported the functions <tt>area()</tt> and
<tt>circumference()</tt>. To export an object, add to the special <tt>exports</tt>
object. (Alternatively, one can use <tt>this</tt> instead of <tt>exports</tt>.) Variables
local to the module will be private. In this example the variable <tt>PI</tt> is
private to <tt>circle.js</tt>. The function <tt>puts()</tt> comes from the module
<tt>"/utils.js"</tt>. Because <tt>include("/utils.js")</tt> was called, <tt>puts()</tt> is in the
global namespace.</p></div>
<div class="paragraph"><p>The module path is relative to the file calling <tt>require()</tt>. That is,
<tt>circle.js</tt> must be in the same directory as <tt>foo.js</tt> for <tt>require()</tt> to
find it.</p></div>
<div class="paragraph"><p>Like <tt>require()</tt> the function <tt>include()</tt> also loads a module. Instead of
returning a namespace object, <tt>include()</tt> will add the module’s exports into
the global namespace. For example:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>include("circle.js");
include("/utils.js");
puts("The area of a cirlce of radius 4 is " + area(4));</tt></pre>
</div></div>
<div class="paragraph"><p>When an absolute path is given to <tt>require()</tt> or <tt>include()</tt>, like
<tt>require("/mjsunit.js")</tt> the module is searched for in the
<tt>node.libraryPaths</tt> array. <tt>node.libraryPaths</tt> on my system looks like this:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>[ "/home/ryan/.node_libraries"
, "/home/ryan/local/node/lib/node_libraries"
, "/"
]</tt></pre>
</div></div>
<div class="paragraph"><p>That is, first Node looks for <tt>"/home/ryan/.node_libraries/mjsunit.js"</tt> and
then for <tt>"/home/ryan/local/node/lib/node_libraries/mjsunit.js"</tt>. If not
found, it finally looks for <tt>"/mjsunit.js"</tt> (in the root directory).</p></div>
<div class="paragraph"><p><tt>node.libraryPaths</tt> can be modified at runtime by simply unshifting new
paths on to it and at startup with the <tt>NODE_LIBRARY_PATHS</tt> environmental
variable (which should be a list of paths, colon separated).</p></div>
<div class="paragraph"><p>Node comes with several libraries which are installed when <tt>"make install"</tt>
is run. These are currently undocumented, but do look them up in your
system.</p></div>
<h3 id="_timers">Timers</h3><div style="clear:left"></div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>setTimeout(callback, delay)</tt>
</dt>
<dd>
<p>
To schedule execution of callback after delay milliseconds. Returns a
<tt>timeoutId</tt> for possible use with <tt>clearTimeout()</tt>.
</p>
</dd>
<dt class="hdlist1">
<tt>clearTimeout(timeoutId)</tt>
</dt>
<dd>
<p>
Prevents said timeout from triggering.
</p>
</dd>
<dt class="hdlist1">
<tt>setInterval(callback, delay)</tt>
</dt>
<dd>
<p>
To schedule the repeated execution of callback every <tt>delay</tt> milliseconds. Returns
a <tt>intervalId</tt> for possible use with <tt>clearInterval()</tt>.
</p>
</dd>
<dt class="hdlist1">
<tt>clearInterval(intervalId)</tt>
</dt>
<dd>
<p>
Stops a interval from triggering.
</p>
</dd>
</dl></div>
<h3 id="_child_processes">Child Processes</h3><div style="clear:left"></div>
<div class="paragraph"><p>Node provides a tridirectional <tt>popen(3)</tt> facility through the class
<tt>node.ChildProcess</tt>. It is possible to stream data through the child’s <tt>stdin</tt>,
<tt>stdout</tt>, and <tt>stderr</tt> in a fully non-blocking way.</p></div>
<h4 id="_tt_node_childprocess_tt"><tt>node.ChildProcess</tt></h4>
<div class="tableblock">
<table rules="all"
width="100%"
frame="border"
cellspacing="0" cellpadding="4">
<col width="7%" />
<col width="15%" />
<col width="76%" />
<thead>
<tr>
<th align="left" valign="top"> Event </th>
<th align="left" valign="top"> Parameters </th>
<th align="left" valign="top">Notes</th>
</tr>
</thead>
<tbody>
<tr>
<td align="left" valign="top"><p class="table"><tt>"output"</tt></p></td>
<td align="left" valign="top"><p class="table"><tt>data</tt></p></td>
<td align="left" valign="top"><p class="table">Each time the child process
sends data to its <tt>stdout</tt>, this event is
emitted. <tt>data</tt> is a string. + If the child
process closes its <tt>stdout</tt> stream (a common
thing to do on exit), this event will be emitted
with <tt>data === null</tt>.</p></td>
</tr>
<tr>
<td align="left" valign="top"><p class="table"><tt>"error"</tt></p></td>
<td align="left" valign="top"><p class="table"><tt>data</tt></p></td>
<td align="left" valign="top"><p class="table">Identical to the <tt>"output"</tt> event except for
<tt>stderr</tt> instead of <tt>stdout</tt>.</p></td>
</tr>
<tr>
<td align="left" valign="top"><p class="table"><tt>"exit"</tt></p></td>
<td align="left" valign="top"><p class="table"><tt>code</tt></p></td>
<td align="left" valign="top"><p class="table">This event is emitted after the child process
ends. <tt>code</tt> is the final exit code of the
process. One can be assured that after this
event is emitted that the <tt>"output"</tt> and
<tt>"error"</tt> callbacks will no longer be made.</p></td>
</tr>
</tbody>
</table>
</div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>node.createChildProcess(command)</tt>
</dt>
<dd>
<p>
Launches a new process with the given <tt>command</tt>. For example:
</p>
<div class="listingblock">
<div class="content">
<pre><tt>var ls = node.createChildProcess("ls -lh /usr");
ls.addListener("output", function (data) {
puts(data);
});</tt></pre>
</div></div>
</dd>
<dt class="hdlist1">
<tt>child.pid</tt>
</dt>
<dd>
<p>
The PID of the child process.
</p>
</dd>
<dt class="hdlist1">
<tt>child.write(data, encoding="ascii")</tt>
</dt>
<dd>
<p>
Write data to the child process’s <tt>stdin</tt>. The second argument is optional and
specifies the encoding: possible values are <tt>"utf8"</tt>, <tt>"ascii"</tt>, and
<tt>"binary"</tt>.
</p>
</dd>
<dt class="hdlist1">
<tt>child.close()</tt>
</dt>
<dd>
<p>
Closes the process’s <tt>stdin</tt> stream.
</p>
</dd>
<dt class="hdlist1">
<tt>child.kill(signal=node.SIGTERM)</tt>
</dt>
<dd>
<p>
Send a single to the child process. If no argument is given, the process
will be sent <tt>node.SIGTERM</tt>. The standard POSIX signals are defined under
the <tt>node</tt> namespace (<tt>node.SIGINT</tt>, <tt>node.SIGUSR1</tt>, …).
</p>
</dd>
</dl></div>
<h3 id="_file_i_o">File I/O</h3><div style="clear:left"></div>
<div class="paragraph"><p>File I/O is provided by simple wrappers around standard POSIX functions.
All POSIX wrappers have a similar form.
They return a promise (<tt>node.Promise</tt>). Example:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>var promise = node.fs.unlink("/tmp/hello");
promise.addCallback(function () {
puts("successfully deleted /tmp/hello");
});</tt></pre>
</div></div>
<div class="paragraph"><p>There is no guaranteed ordering to the POSIX wrappers. The
following is very much prone to error</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>node.fs.rename("/tmp/hello", "/tmp/world");
node.fs.stat("/tmp/world").addCallback(function (stats) {
puts("stats: " + JSON.stringify(stats));
});</tt></pre>
</div></div>
<div class="paragraph"><p>It could be that <tt>stat()</tt> is executed before the <tt>rename()</tt>.
The correct way to do this is to chain the promises.</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>node.fs.rename("/tmp/hello", "/tmp/world").addCallback(function () {
node.fs.stat("/tmp/world").addCallback(function (stats) {
puts("stats: " + JSON.stringify(stats));
});
});</tt></pre>
</div></div>
<div class="paragraph"><p>Or use the <tt>promise.wait()</tt> functionality:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>node.fs.rename("/tmp/hello", "/tmp/world").wait();
node.fs.stat("/tmp/world").addCallback(function (stats) {
puts("stats: " + JSON.stringify(stats));
});</tt></pre>
</div></div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>node.fs.rename(path1, path2)</tt>
</dt>
<dd>
<p>
See rename(2).
</p>
<div class="ulist"><ul>
<li>
<p>
on success: no parameters.
</p>
</li>
<li>
<p>
on error: no parameters.
</p>
</li>
</ul></div>
</dd>
<dt class="hdlist1">
<tt>node.fs.stat(path)</tt>
</dt>
<dd>
<p>
See stat(2).
</p>
<div class="ulist"><ul>
<li>
<p>
on success: Returns <tt>node.fs.Stats</tt> object. It looks like this:
<tt>{ dev: 2049, ino: 305352, mode: 16877, nlink: 12, uid: 1000, gid: 1000,
rdev: 0, size: 4096, blksize: 4096, blocks: 8, atime:
"2009-06-29T11:11:55Z", mtime: "2009-06-29T11:11:40Z", ctime:
"2009-06-29T11:11:40Z" }</tt>
See the <tt>node.fs.Stats</tt> section below for more information.
</p>
</li>
<li>
<p>
on error: no parameters.
</p>
</li>
</ul></div>
</dd>
<dt class="hdlist1">
<tt>node.fs.unlink(path)</tt>
</dt>
<dd>
<p>
See unlink(2)
</p>
<div class="ulist"><ul>
<li>
<p>
on success: no parameters.
</p>
</li>
<li>
<p>
on error: no parameters.
</p>
</li>
</ul></div>
</dd>
<dt class="hdlist1">
<tt>node.fs.rmdir(path)</tt>
</dt>
<dd>
<p>
See rmdir(2)
</p>
<div class="ulist"><ul>
<li>
<p>
on success: no parameters.
</p>
</li>
<li>
<p>
on error: no parameters.
</p>
</li>
</ul></div>
</dd>
<dt class="hdlist1">
<tt>node.fs.mkdir(path, mode)</tt>
</dt>
<dd>
<p>
See mkdir(2)
</p>
<div class="ulist"><ul>
<li>
<p>
on success: no parameters.
</p>
</li>
<li>
<p>
on error: no parameters.
</p>
</li>
</ul></div>
</dd>
<dt class="hdlist1">
<tt>node.fs.readdir(path)</tt>
</dt>
<dd>
<p>
Reads the contents of a directory.
</p>
<div class="ulist"><ul>
<li>
<p>
on success: One argument, an array containing the names (strings) of the
files in the directory (excluding "." and "..").
</p>
</li>
<li>
<p>
on error: no parameters.
</p>
</li>
</ul></div>
</dd>
<dt class="hdlist1">
<tt>node.fs.close(fd)</tt>
</dt>
<dd>
<p>
See close(2)
</p>
<div class="ulist"><ul>
<li>
<p>
on success: no parameters.
</p>
</li>
<li>
<p>
on error: no parameters.
</p>
</li>
</ul></div>
</dd>
<dt class="hdlist1">
<tt>node.fs.open(path, flags, mode)</tt>
</dt>
<dd>
<p>
See open(2). The constants like <tt>O_CREAT</tt> are defined at <tt>node.O_CREAT</tt>.
</p>
<div class="ulist"><ul>
<li>
<p>
on success: <tt>fd</tt> is given as the parameter.
</p>
</li>
<li>
<p>
on error: no parameters.
</p>
</li>
</ul></div>
</dd>
<dt class="hdlist1">
<tt>node.fs.write(fd, data, position, encoding)</tt>
</dt>
<dd>
<p>
Write data to the file specified by <tt>fd</tt>. <tt>position</tt> refers to the offset
from the beginning of the file where this data should be written. If
<tt>position</tt> is <tt>null</tt>, the data will be written at the current position.
See pwrite(2).
</p>
<div class="ulist"><ul>
<li>
<p>
on success: returns an integer <tt>written</tt> which specifies how many <em>bytes</em> were written.
</p>
</li>
<li>
<p>
on error: no parameters.
</p>
</li>
</ul></div>
</dd>
<dt class="hdlist1">
<tt>node.fs.read(fd, length, position, encoding)</tt>
</dt>
<dd>
<p>
Read data from the file specified by <tt>fd</tt>.
</p>
<div class="paragraph"><p><tt>length</tt> is an integer specifying the number of
bytes to read.</p></div>
<div class="paragraph"><p><tt>position</tt> is an integer specifying where to begin
reading from in the file.</p></div>
<div class="ulist"><ul>
<li>
<p>
on success: returns <tt>data, bytes_read</tt>, what was read from the file.
</p>
</li>
<li>
<p>
on error: no parameters.
</p>
</li>
</ul></div>
</dd>
<dt class="hdlist1">
<tt>node.fs.cat(filename, encoding="utf8")</tt>
</dt>
<dd>
<p>
Outputs the entire contents of a file. Example:
</p>
<div class="listingblock">
<div class="content">
<pre><tt>node.fs.cat("/etc/passwd").addCallback(function (content) {
puts(content);
});</tt></pre>
</div></div>
<div class="ulist"><ul>
<li>
<p>
on success: returns <tt>data</tt>, what was read from the file.
</p>
</li>
<li>
<p>
on error: no parameters.
</p>
</li>
</ul></div>
</dd>
</dl></div>
<h4 id="_tt_node_fs_stats_tt"><tt>node.fs.Stats</tt></h4>
<div class="paragraph"><p>Objects returned from <tt>node.fs.stat()</tt> are of this type.</p></div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>stats.isFile()</tt>
</dt>
<dt class="hdlist1">
<tt>stats.isDirectory()</tt>
</dt>
<dt class="hdlist1">
<tt>stats.isBlockDevice()</tt>
</dt>
<dt class="hdlist1">
<tt>stats.isCharacterDevice()</tt>
</dt>
<dt class="hdlist1">
<tt>stats.isSymbolicLink()</tt>
</dt>
<dt class="hdlist1">
<tt>stats.isFIFO()</tt>
</dt>
<dt class="hdlist1">
<tt>stats.isSocket()</tt>
</dt>
<dd>
<p>
…
</p>
</dd>
</dl></div>
<h3 id="_http">HTTP</h3><div style="clear:left"></div>
<div class="paragraph"><p>To use the HTTP server and client one must <tt>require("/http.js")</tt> or
<tt>include("/http.js")</tt>.</p></div>
<div class="paragraph"><p>The HTTP interfaces in Node are designed to support many features
of the protocol which have been traditionally difficult to use.
In particular, large, possibly chunk-encoded, messages. The interface is
careful to never buffer entire requests or responses—the
user is able to stream data.</p></div>
<div class="paragraph"><p>HTTP message headers are represented by an object like this</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>{ "Content-Length": "123"
, "Content-Type": "text/plain"
, "Connection": "keep-alive"
, "Accept": "*/*"
}</tt></pre>
</div></div>
<div class="paragraph"><p>In order to support the full spectrum of possible HTTP applications, Node’s
HTTP API is very low-level. It deals with connection handling and message
parsing only. It parses a message into headers and body but it does not
parse the actual headers or the body.</p></div>
<h4 id="_tt_http_server_tt"><tt>http.Server</tt></h4>
<div class="tableblock">
<table rules="all"
width="100%"
frame="border"
cellspacing="0" cellpadding="4">
<col width="7%" />
<col width="15%" />
<col width="76%" />
<thead>
<tr>
<th align="left" valign="top">Event </th>
<th align="left" valign="top"> Parameters </th>
<th align="left" valign="top"> Notes</th>
</tr>
</thead>
<tbody>
<tr>
<td align="left" valign="top"><p class="table"><tt>"request"</tt></p></td>
<td align="left" valign="top"><p class="table"><tt>request, response</tt></p></td>
<td align="left" valign="top"><p class="table"><tt>request</tt> is an instance of <tt>http.ServerRequest</tt>
<br />
<tt>response</tt> is an instance of <tt>http.ServerResponse</tt></p></td>
</tr>
<tr>
<td align="left" valign="top"><p class="table"><tt>"connection"</tt></p></td>
<td align="left" valign="top"><p class="table"><tt>connection</tt></p></td>
<td align="left" valign="top"><p class="table">When a new TCP connection is established.
<tt>connection</tt> is an object of type
<tt>http.Connection</tt>. Usually users
will not want to access this event.
The <tt>connection</tt> can also be
accessed at <tt>request.connection</tt>.</p></td>
</tr>
<tr>
<td align="left" valign="top"><p class="table"><tt>"close"</tt></p></td>
<td align="left" valign="top"><p class="table"><tt>errorno</tt></p></td>
<td align="left" valign="top"><p class="table">Emitted when the server closes. <tt>errorno</tt>
is an integer which indicates what, if any,
error caused the server to close. If no
error occured <tt>errorno</tt> will be 0.</p></td>
</tr>
</tbody>
</table>
</div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>http.createServer(request_listener, options);</tt>
</dt>
<dd>
<p>
Returns a new web server object.
</p>
<div class="paragraph"><p>The <tt>options</tt> argument is optional. The
<tt>options</tt> argument accepts the same values as the
options argument for <tt>tcp.Server</tt> does.</p></div>
<div class="paragraph"><p>The <tt>request_listener</tt> is a function which is automatically
added to the <tt>"request"</tt> event.</p></div>
</dd>
<dt class="hdlist1">
<tt>server.listen(port, hostname)</tt>
</dt>
<dd>
<p>
Begin accepting connections on the specified port and hostname.
If the hostname is omitted, the server will accept connections
directed to any address. This function is synchronous.
</p>
</dd>
<dt class="hdlist1">
<tt>server.close()</tt>
</dt>
<dd>
<p>
Stops the server from accepting new connections.
</p>
</dd>
</dl></div>
<h4 id="_tt_http_serverrequest_tt"><tt>http.ServerRequest</tt></h4>
<div class="paragraph"><p>This object is created internally by a HTTP server—not by
the user—and passed as the first argument to a <tt>"request"</tt> listener.</p></div>
<div class="tableblock">
<table rules="all"
width="100%"
frame="border"
cellspacing="0" cellpadding="4">
<col width="7%" />
<col width="15%" />
<col width="76%" />
<thead>
<tr>
<th align="left" valign="top">Event </th>
<th align="left" valign="top"> Parameters </th>
<th align="left" valign="top"> Notes</th>
</tr>
</thead>
<tbody>
<tr>
<td align="left" valign="top"><p class="table"><tt>"body"</tt></p></td>
<td align="left" valign="top"><p class="table"><tt>chunk</tt></p></td>
<td align="left" valign="top"><p class="table">Emitted when a piece of the
message body is received. Example: A chunk
of the body is given as the single
argument. The transfer-encoding has been
decoded. The body chunk is a String. The
body encoding is set with
<tt>request.setBodyEncoding()</tt>.</p></td>
</tr>
<tr>
<td align="left" valign="top"><p class="table"><tt>"complete"</tt></p></td>
<td align="left" valign="top"><p class="table">(none)</p></td>
<td align="left" valign="top"><p class="table">Emitted exactly once for each message.
No arguments. After emitted no other
events will be emitted on the request.</p></td>
</tr>
</tbody>
</table>
</div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>request.method</tt>
</dt>
<dd>
<p>
The request method as a string. Read only. Example:
<tt>"GET"</tt>, <tt>"DELETE"</tt>.
</p>
</dd>
<dt class="hdlist1">
<tt>request.uri</tt>
</dt>
<dd>
<p>
Request URI Object. This contains only the parameters that are
present in the actual HTTP request. That is, if the request is
</p>
<div class="listingblock">
<div class="content">
<pre><tt>GET /status?name=ryan HTTP/1.1\r\n
Accept: text/plain\r\n
\r\n</tt></pre>
</div></div>
<div class="paragraph"><p>Then <tt>request.uri</tt> will be</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>{ path: "/status",
file: "status",
directory: "/",
params: { "name" : "ryan" }
}</tt></pre>
</div></div>
<div class="paragraph"><p>In particular, note that <tt>request.uri.protocol</tt> is
<tt>undefined</tt>. This is because there was no URI protocol given
in the actual HTTP Request.</p></div>
<div class="paragraph"><p>Here is what’s available: <tt>request.uri.anchor</tt>, <tt>request.uri.query</tt>,
<tt>request.uri.file</tt>, <tt>request.uri.directory</tt>, <tt>request.uri.path</tt>,
<tt>request.uri.relative</tt>, <tt>request.uri.port</tt>, <tt>request.uri.host</tt>,
<tt>request.uri.password</tt>, <tt>request.uri.user</tt>, <tt>request.uri.authority</tt>,
<tt>request.uri.protocol</tt>, <tt>request.uri.params</tt>, <tt>request.uri.toString()</tt>,
<tt>request.uri.source</tt></p></div>
</dd>
<dt class="hdlist1">
<tt>request.headers</tt>
</dt>
<dd>
<p>
Read only.
</p>
</dd>
<dt class="hdlist1">
<tt>request.httpVersion</tt>
</dt>
<dd>
<p>
The HTTP protocol version as a string. Read only. Examples:
<tt>"1.1"</tt>, <tt>"1.0"</tt>
</p>
</dd>
<dt class="hdlist1">
<tt>request.setBodyEncoding(encoding)</tt>
</dt>
<dd>
<p>
Set the encoding for the request body. Either <tt>"utf8"</tt> or <tt>"binary"</tt>. Defaults
to <tt>"binary"</tt>.
</p>
</dd>
<dt class="hdlist1">
<tt>request.pause()</tt>
</dt>
<dd>
<p>
Pauses request from emitting events. Useful to throttle back an upload.
</p>
</dd>
<dt class="hdlist1">
<tt>request.resume()</tt>
</dt>
<dd>
<p>
Resumes a paused request.
</p>
</dd>
<dt class="hdlist1">
<tt>request.connection</tt>
</dt>
<dd>
<p>
The <tt>http.Connection</tt> object.
</p>
</dd>
</dl></div>
<h4 id="_tt_http_serverresponse_tt"><tt>http.ServerResponse</tt></h4>
<div class="paragraph"><p>This object is created internally by a HTTP server—not by the user. It is
passed as the second parameter to the <tt>"request"</tt> event.</p></div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>response.sendHeader(statusCode, headers)</tt>
</dt>
<dd>
<p>
Sends a response header to the request. The status code is a 3-digit HTTP
status code, like <tt>404</tt>. The second argument, <tt>headers</tt> are the response headers.
</p>
<div class="paragraph"><p>Example:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>var body = "hello world";
response.sendHeader(200, {
"Content-Length": body.length,
"Content-Type": "text/plain"
});</tt></pre>
</div></div>
<div class="paragraph"><p>This method must only be called once on a message and it must
be called before <tt>response.finish()</tt> is called.</p></div>
</dd>
<dt class="hdlist1">
<tt>response.sendBody(chunk, encoding="ascii")</tt>
</dt>
<dd>
<p>
This method must be called after <tt>sendHeader</tt> was
called. It sends a chunk of the response body. This method may
be called multiple times to provide successive parts of the body.
</p>
<div class="paragraph"><p>If <tt>chunk</tt> is a string, the second parameter
specifies how to encode it into a byte stream. By default the
<tt>encoding</tt> is <tt>"ascii"</tt>.</p></div>
<div class="paragraph"><p>Note: This is the raw HTTP body and has nothing to do with
higher-level multi-part body encodings that may be used.</p></div>
<div class="paragraph"><p>The first time <tt>sendBody</tt> is called, it will send the buffered header
information and the first body to the client. The second time
<tt>sendBody</tt> is called, Node assumes you’re going to be streaming data, and
sends that seperately. That is, the response is buffered up to the
first chunk of body.</p></div>
</dd>
<dt class="hdlist1">
<tt>response.finish()</tt>
</dt>
<dd>
<p>
This method signals to the server that all of the response headers and body
has been sent; that server should consider this message complete.
The method, <tt>response.finish()</tt>, MUST be called on each
response.
</p>
</dd>
</dl></div>
<h4 id="_tt_http_client_tt"><tt>http.Client</tt></h4>
<div class="paragraph"><p>An HTTP client is constructed with a server address as its
argument, the returned handle is then used to issue one or more
requests. Depending on the server connected to, the client might
pipeline the requests or reestablish the connection after each
connection. <em>Currently the implementation does not pipeline requests.</em></p></div>
<div class="paragraph"><p>Example of connecting to <tt>google.com</tt></p></div>
<div class="listingblock">
<div class="content">
<pre><tt>var google = http.createClient(80, "google.com");
var request = google.get("/");
request.finish(function (response) {
puts("STATUS: " + response.statusCode);
puts("HEADERS: " + JSON.stringify(response.headers));
response.setBodyEncoding("utf8");
response.addListener("body", function (chunk) {
puts("BODY: " + chunk);
});
});</tt></pre>
</div></div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>http.createClient(port, host)</tt>
</dt>
<dd>
<p>
Constructs a new HTTP client. <tt>port</tt> and
<tt>host</tt> refer to the server to be connected to. A
connection is not established until a request is issued.
</p>
</dd>
<dt class="hdlist1">
<tt>client.get(path, request_headers)</tt>, <tt>client.head(path, request_headers)</tt>, <tt>client.post(path, request_headers)</tt>, <tt>client.del(path, request_headers)</tt>, <tt>client.put(path, request_headers)</tt>
</dt>
<dd>
<p>
Issues a request; if necessary establishes connection. Returns a <tt>http.ClientRequest</tt> instance.
</p>
<div class="paragraph"><p><tt>request_headers</tt> is optional.
Additional request headers might be added internally
by Node. Returns a <tt>ClientRequest</tt> object.</p></div>
<div class="paragraph"><p>Do remember to include the <tt>Content-Length</tt> header if you
plan on sending a body. If you plan on streaming the body, perhaps
set <tt>Transfer-Encoding: chunked</tt>.</p></div>
<div class="admonitionblock">
<table><tr>
<td class="icon">
<div class="title">Note</div>
</td>
<td class="content">the request is not complete. This method only sends
the header of the request. One needs to call
<tt>request.finish()</tt> to finalize the request and retrieve
the response. (This sounds convoluted but it provides a chance
for the user to stream a body to the server with
<tt>request.sendBody()</tt>.)</td>
</tr></table>
</div>
</dd>
</dl></div>
<h4 id="_tt_http_clientrequest_tt"><tt>http.ClientRequest</tt></h4>
<div class="paragraph"><p>This object is created internally and returned from the request methods of a
<tt>http.Client</tt>. It represents an <em>in-progress</em> request whose header has
already been sent.</p></div>
<div class="tableblock">
<table rules="all"
width="100%"
frame="border"
cellspacing="0" cellpadding="4">
<col width="7%" />
<col width="15%" />
<col width="76%" />
<thead>
<tr>
<th align="left" valign="top">Event </th>
<th align="left" valign="top"> Parameters </th>
<th align="left" valign="top"> Notes</th>
</tr>
</thead>
<tbody>
<tr>
<td align="left" valign="top"><p class="table"><tt>"response"</tt></p></td>
<td align="left" valign="top"><p class="table"><tt>response</tt></p></td>
<td align="left" valign="top"><p class="table">Emitted when a response is received to this request. Typically the user will
set a listener to this via the <tt>request.finish()</tt> method.<br />
This event is emitted only once.<br />
The <tt>response</tt> argument will be an instance of <tt>http.ClientResponse</tt>.</p></td>
</tr>
</tbody>
</table>
</div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>request.sendBody(chunk, encoding="ascii")</tt>
</dt>
<dd>
<p>
Sends a chunk of the body. By calling this method
many times, the user can stream a request body to a
server—in that case it is suggested to use the
<tt>["Transfer-Encoding", "chunked"]</tt> header line when
creating the request.
</p>
<div class="paragraph"><p>The <tt>chunk</tt> argument should be an array of integers
or a string.</p></div>
<div class="paragraph"><p>The <tt>encoding</tt> argument is optional and only
applies when <tt>chunk</tt> is a string. The encoding
argument should be either <tt>"utf8"</tt> or
<tt>"ascii"</tt>. By default the body uses ASCII encoding,
as it is faster.</p></div>
</dd>
<dt class="hdlist1">
<tt>request.finish(responseListener)</tt>
</dt>
<dd>
<p>
Finishes sending the request. If any parts of the body are
unsent, it will flush them to the socket. If the request is
chunked, this will send the terminating <tt>"0\r\n\r\n"</tt>.
</p>
<div class="paragraph"><p>The parameter <tt>responseListener</tt> is a callback which
will be executed when the response headers have been received.
The <tt>responseListener</tt> callback is executed with one
argument which is an instance of <tt>http.ClientResponse</tt>.</p></div>
<div class="paragraph"><p>In the <tt>responseListener</tt> callback, one can add more listeners to the
response, in particular listening for the <tt>"body"</tt> event. Note that
the <tt>responseListener</tt> is called before any part of the body is receieved,
so there is no need to worry about racing to catch the first part of the
body. As long as a listener for <tt>"body"</tt> is added during the
<tt>responseListener</tt> callback, the entire body will be caught.</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>// Good
request.finish(function (response) {
response.addListener("body", function (chunk) {
puts("BODY: " + chunk);
});
});
// Bad - misses all or part of the body
request.finish(function (response) {
setTimeout(function () {
response.addListener("body", function (chunk) {
puts("BODY: " + chunk);
});
}, 10);
});</tt></pre>
</div></div>
</dd>
</dl></div>
<h4 id="_tt_http_clientresponse_tt"><tt>http.ClientResponse</tt></h4>
<div class="paragraph"><p>This object is created internally and passed to the <tt>"response"</tt> event.</p></div>
<div class="tableblock">
<table rules="all"
width="100%"
frame="border"
cellspacing="0" cellpadding="4">
<col width="7%" />
<col width="15%" />
<col width="76%" />
<thead>
<tr>
<th align="left" valign="top">Event </th>
<th align="left" valign="top"> Parameters </th>
<th align="left" valign="top"> Notes</th>
</tr>
</thead>
<tbody>
<tr>
<td align="left" valign="top"><p class="table"><tt>"body"</tt></p></td>
<td align="left" valign="top"><p class="table"><tt>chunk</tt></p></td>
<td align="left" valign="top"><p class="table">Emitted when a piece of the message body is received. Example: A chunk of
the body is given as the single argument. The transfer-encoding has been
decoded. The body chunk a String. The body encoding is set with
<tt>response.setBodyEncoding()</tt>.</p></td>
</tr>
<tr>
<td align="left" valign="top"><p class="table"><tt>"complete"</tt></p></td>
<td align="left" valign="top"><p class="table"></p></td>
<td align="left" valign="top"><p class="table">Emitted exactly once for each message. No arguments.
After emitted no other events will be emitted on the response.</p></td>
</tr>
</tbody>
</table>
</div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>response.statusCode</tt>
</dt>
<dd>
<p>
The 3-digit HTTP response status code. E.G. <tt>404</tt>.
</p>
</dd>
<dt class="hdlist1">
<tt>response.httpVersion</tt>
</dt>
<dd>
<p>
The HTTP version of the connected-to server. Probably either
<tt>"1.1"</tt> or <tt>"1.0"</tt>.
</p>
</dd>
<dt class="hdlist1">
<tt>response.headers</tt>
</dt>
<dd>
<p>
The response headers.
</p>
</dd>
<dt class="hdlist1">
<tt>response.setBodyEncoding(encoding)</tt>
</dt>
<dd>
<p>
Set the encoding for the response body. Either <tt>"utf8"</tt> or <tt>"binary"</tt>.
Defaults to <tt>"binary"</tt>.
</p>
</dd>
<dt class="hdlist1">
<tt>response.pause()</tt>
</dt>
<dd>
<p>
Pauses response from emitting events. Useful to throttle back a download.
</p>
</dd>
<dt class="hdlist1">
<tt>response.resume()</tt>
</dt>
<dd>
<p>
Resumes a paused response.
</p>
</dd>
<dt class="hdlist1">
<tt>response.client</tt>
</dt>
<dd>
<p>
A reference to the <tt>http.Client</tt> that this response belongs to.
</p>
</dd>
</dl></div>
<h3 id="_tcp">TCP</h3><div style="clear:left"></div>
<div class="paragraph"><p>To use the TCP server and client one must <tt>require("/tcp.js")</tt> or
<tt>include("/tcp.js")</tt>.</p></div>
<h4 id="_tt_tcp_server_tt"><tt>tcp.Server</tt></h4>
<div class="paragraph"><p>Here is an example of a echo server which listens for connections
on port 7000</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>include("/tcp.js");
var server = createServer(function (socket) {
socket.setEncoding("utf8");
socket.addListener("connect", function () {
socket.send("hello\r\n");
});
socket.addListener("receive", function (data) {
socket.send(data);
});
socket.addListener("eof", function () {
socket.send("goodbye\r\n");
socket.close();
});
});
server.listen(7000, "localhost");</tt></pre>
</div></div>
<div class="tableblock">
<table rules="all"
width="100%"
frame="border"
cellspacing="0" cellpadding="4">
<col width="7%" />
<col width="15%" />
<col width="76%" />
<thead>
<tr>
<th align="left" valign="top">Event </th>
<th align="left" valign="top"> Parameters </th>
<th align="left" valign="top"> Notes</th>
</tr>
</thead>
<tbody>
<tr>
<td align="left" valign="top"><p class="table"><tt>"connection"</tt></p></td>
<td align="left" valign="top"><p class="table"><tt>connection</tt></p></td>
<td align="left" valign="top"><p class="table">Emitted when a new connection is made.
<tt>connection</tt> is an instance of <tt>tcp.Connection</tt>.</p></td>
</tr>
<tr>
<td align="left" valign="top"><p class="table"><tt>"close"</tt></p></td>
<td align="left" valign="top"><p class="table"><tt>errorno</tt></p></td>
<td align="left" valign="top"><p class="table">Emitted when the server closes. <tt>errorno</tt>
is an integer which indicates what, if any,
error caused the server to close. If no
error occurred <tt>errorno</tt> will be 0.</p></td>
</tr>
</tbody>
</table>
</div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>tcp.createServer(connection_listener);</tt>
</dt>
<dd>
<p>
Creates a new TCP server.
</p>
<div class="paragraph"><p>The <tt>connection_listener</tt> argument is automatically set as a listener for
the <tt>"connection"</tt> event.</p></div>
</dd>
<dt class="hdlist1">
<tt>server.listen(port, host=null, backlog=128)</tt>
</dt>
<dd>
<p>
Tells the server to listen for TCP connections to <tt>port</tt> and <tt>host</tt>.
</p>
<div class="paragraph"><p><tt>host</tt> is optional. If <tt>host</tt> is not specified the server will accept client
connections on any network address.</p></div>
<div class="paragraph"><p>The third argument, <tt>backlog</tt>, is also optional and defaults to 128. The
<tt>backlog</tt> argument defines the maximum length to which the queue of pending
connections for the server may grow.</p></div>
<div class="paragraph"><p>This function is synchronous.</p></div>
</dd>
<dt class="hdlist1">
<tt>server.close()</tt>
</dt>
<dd>
<p>
Stops the server from accepting new connections. This function is
asynchronous, the server is finally closed when the server emits a <tt>"close"</tt>
event.
</p>
</dd>
</dl></div>
<h4 id="_tt_tcp_connection_tt"><tt>tcp.Connection</tt></h4>
<div class="paragraph"><p>This object is used as a TCP client and also as a server-side
socket for <tt>tcp.Server</tt>.</p></div>
<div class="tableblock">
<table rules="all"
width="100%"
frame="border"
cellspacing="0" cellpadding="4">
<col width="7%" />
<col width="15%" />
<col width="76%" />
<thead>
<tr>
<th align="left" valign="top">Event </th>
<th align="left" valign="top"> Parameters </th>
<th align="left" valign="top"> Notes</th>
</tr>
</thead>
<tbody>
<tr>
<td align="left" valign="top"><p class="table"><tt>"connect"</tt></p></td>
<td align="left" valign="top"><p class="table"></p></td>
<td align="left" valign="top"><p class="table">Call once the connection is established
after a call to <tt>createConnection()</tt> or
<tt>connect()</tt>.</p></td>
</tr>
<tr>
<td align="left" valign="top"><p class="table"><tt>"receive"</tt></p></td>
<td align="left" valign="top"><p class="table"><tt>data</tt></p></td>
<td align="left" valign="top"><p class="table">Called when data is received on the
connection. <tt>data</tt> will be a string.
Encoding of data is set by
<tt>connection.setEncoding()</tt>.</p></td>
</tr>
<tr>
<td align="left" valign="top"><p class="table"><tt>"eof"</tt></p></td>
<td align="left" valign="top"><p class="table"></p></td>
<td align="left" valign="top"><p class="table">Called when the other end of the
connection sends a FIN packet.
After this is emitted the <tt>readyState</tt>
will be <tt>"writeOnly"</tt>. One should probably
just call <tt>connection.close()</tt> when this
event is emitted.</p></td>
</tr>
<tr>
<td align="left" valign="top"><p class="table"><tt>"timeout"</tt></p></td>
<td align="left" valign="top"><p class="table"></p></td>
<td align="left" valign="top"><p class="table">Emitted if the connection times out from
inactivity. The <tt>"close"</tt> event will be
emitted immediately following this event.</p></td>
</tr>
<tr>
<td align="left" valign="top"><p class="table"><tt>"close"</tt></p></td>
<td align="left" valign="top"><p class="table"><tt>had_error</tt></p></td>
<td align="left" valign="top"><p class="table">Emitted once the connection is fully
closed. The argument <tt>had_error</tt>
is a boolean which says if the connection
was closed due to a transmission error.
(TODO: access error codes.)</p></td>
</tr>
</tbody>
</table>
</div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>tcp.createConnection(port, host="127.0.0.1")</tt>
</dt>
<dd>
<p>
Creates a new connection object and opens a connection to the specified
<tt>port</tt> and <tt>host</tt>. If the second parameter is omitted, localhost is assumed.
</p>
<div class="paragraph"><p>When the connection is established the <tt>"connect"</tt> event will be emitted.</p></div>
</dd>
<dt class="hdlist1">
<tt>connection.connect(port, host="127.0.0.1")</tt>
</dt>
<dd>
<p>
Opens a connection to the specified <tt>port</tt> and <tt>host</tt>. <tt>createConnection()</tt>
also opens a connection; normally this method is not needed. Use this only
if a connection is closed and you want to reuse the object to connect to
another server.
</p>
<div class="paragraph"><p>This function is asynchronous. When the <tt>"connect"</tt> event is emitted the
connection is established. If there is a problem connecting, the <tt>"connect"</tt>
event will not be emitted, the <tt>"close"</tt> event will be emitted with
<tt>had_error == true</tt>.</p></div>
</dd>
<dt class="hdlist1">
<tt>connection.remoteAddress</tt>
</dt>
<dd>
<p>
The string representation of the remote IP address. For example,
<tt>"74.125.127.100"</tt> or <tt>"2001:4860:a005::68"</tt>.
</p>
<div class="paragraph"><p>This member is only present in server-side connections.</p></div>
</dd>
<dt class="hdlist1">
<tt>connection.readyState</tt>
</dt>
<dd>
<p>
Either <tt>"closed"</tt>, <tt>"open"</tt>, <tt>"opening"</tt>, <tt>"readOnly"</tt>, or <tt>"writeOnly"</tt>.
</p>
</dd>
<dt class="hdlist1">
<tt>connection.setEncoding(encoding)</tt>
</dt>
<dd>
<p>
Sets the encoding (either <tt>"ascii"</tt>, <tt>"utf8"</tt>, or <tt>"binary"</tt>) for data that is received.
</p>
</dd>
<dt class="hdlist1">
<tt>connection.send(data, encoding="ascii")</tt>
</dt>
<dd>
<p>
Sends data on the connection. The second parameter specifies the encoding
in the case of a string—it defaults to ASCII because encoding to UTF8 is
rather slow.
</p>
</dd>
<dt class="hdlist1">
<tt>connection.close()</tt>
</dt>
<dd>
<p>
Half-closes the connection. I.E., it sends a FIN packet. It is
possible the server will still send some data. After calling
this <tt>readyState</tt> will be <tt>"readOnly"</tt>.
</p>
</dd>
<dt class="hdlist1">
<tt>connection.forceClose()</tt>
</dt>
<dd>
<p>
Ensures that no more I/O activity happens on this socket. Only
necessary in case of errors (parse error or so).
</p>
</dd>
<dt class="hdlist1">
<tt>connection.readPause()</tt>
</dt>
<dd>
<p>
Pauses the reading of data. That is, <tt>"receive"</tt> events will not be emitted.
Useful to throttle back an upload.
</p>
</dd>
<dt class="hdlist1">
<tt>connection.readResume()</tt>
</dt>
<dd>
<p>
Resumes reading if reading was paused by <tt>readPause()</tt>.
</p>
</dd>
<dt class="hdlist1">
<tt>connection.setTimeout(timeout)</tt>
</dt>
<dd>
<p>
Sets the connection to timeout after <tt>timeout</tt> milliseconds of inactivity on
the connection. By default all <tt>tcp.Connection</tt> objects have a timeout
of 60 seconds (60000 ms).
</p>
<div class="paragraph"><p>If <tt>timeout</tt> is 0, then the idle timeout is disabled.</p></div>
</dd>
<dt class="hdlist1">
<tt>connection.setNoDelay(noDelay=true)</tt>
</dt>
<dd>
<p>
Disables the Nagle algorithm. By default TCP connections use the Nagle
algorithm, they buffer data before sending it off. Setting <tt>noDelay</tt> will
immediately fire off data each time <tt>connection.send()</tt> is called.
</p>
</dd>
</dl></div>
<h3 id="_dns">DNS</h3><div style="clear:left"></div>
<div class="paragraph"><p>Here is an example of which resolves <tt>"www.google.com"</tt> then reverse
resolves the IP addresses which are returned.</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>var resolution = node.dns.resolve4("www.google.com");
resolution.addCallback(function (addresses, ttl, cname) {
puts("addresses: " + JSON.stringify(addresses));
puts("ttl: " + JSON.stringify(ttl));
puts("cname: " + JSON.stringify(cname));
for (var i = 0; i < addresses.length; i++) {
var a = addresses[i];
var reversing = node.dns.reverse(a);
reversing.addCallback( function (domains, ttl, cname) {
puts("reverse for " + a + ": " + JSON.stringify(domains));
});
reversing.addErrback( function (code, msg) {
puts("reverse for " + a + " failed: " + msg);
});
}
});
resolution.addErrback(function (code, msg) {
puts("error: " + msg);
});</tt></pre>
</div></div>
<div class="dlist"><dl>
<dt class="hdlist1">
<tt>node.dns.resolve4(domain)</tt>
</dt>
<dd>
<p>
Resolves a domain (e.g. <tt>"google.com"</tt>) into an array of IPv4 addresses (e.g.
<tt>["74.125.79.104", "74.125.79.105", "74.125.79.106"]</tt>).
This function returns a promise.
</p>
<div class="ulist"><ul>
<li>
<p>
on success: returns <tt>addresses, ttl, cname</tt>. <tt>ttl</tt> (time-to-live) is an integer
specifying the number of seconds this result is valid for. <tt>cname</tt> is the
canonical name for the query.
</p>
</li>
<li>
<p>
on error: returns <tt>code, msg</tt>. <tt>code</tt> is one of the error codes listed
below and <tt>msg</tt> is a string describing the error in English.
</p>
</li>
</ul></div>
</dd>
<dt class="hdlist1">
<tt>node.dns.resolve6(domain)</tt>
</dt>
<dd>
<p>
The same as <tt>node.dns.resolve4()</tt> except for IPv6 queries (an <tt>AAAA</tt> query).
</p>
</dd>
<dt class="hdlist1">
<tt>node.dns.reverse(ip)</tt>
</dt>
<dd>
<p>
Reverse resolves an ip address to an array of domain names.
</p>
<div class="ulist"><ul>
<li>
<p>
on success: returns <tt>domains, ttl, cname</tt>. <tt>ttl</tt> (time-to-live) is an integer
specifying the number of seconds this result is valid for. <tt>cname</tt> is the
canonical name for the query. <tt>domains</tt> is an array of domains.
</p>
</li>
<li>
<p>
on error: returns <tt>code, msg</tt>. <tt>code</tt> is one of the error codes listed
below and <tt>msg</tt> is a string describing the error in English.
</p>
</li>
</ul></div>
</dd>
</dl></div>
<div class="paragraph"><p>Each DNS query can return an error code.</p></div>
<div class="ulist"><ul>
<li>
<p>
<tt>node.dns.TEMPFAIL</tt>: timeout, SERVFAIL or similar.
</p>
</li>
<li>
<p>
<tt>node.dns.PROTOCOL</tt>: got garbled reply.
</p>
</li>
<li>
<p>
<tt>node.dns.NXDOMAIN</tt>: domain does not exists.
</p>
</li>
<li>
<p>
<tt>node.dns.NODATA</tt>: domain exists but no data of reqd type.
</p>
</li>
<li>
<p>
<tt>node.dns.NOMEM</tt>: out of memory while processing.
</p>
</li>
<li>
<p>
<tt>node.dns.BADQUERY</tt>: the query is malformed.
</p>
</li>
</ul></div>
</div>
<h2 id="_repl">REPL</h2>
<div class="sectionbody">
<div class="paragraph"><p>A Read-Eval-Print-Loop is available both as a standalone program and easily
includable in other programs.</p></div>
<div class="paragraph"><p>The standalone REPL is called <tt>node-repl</tt> and is installed at
<tt>$PREFIX/bin/node-repl</tt>. It’s recommended to use it with the program
<tt>rlwrap</tt> for a better user interface. I set</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>alias node-repl="rlwrap node-repl"</tt></pre>
</div></div>
<div class="paragraph"><p>in my zsh configuration.</p></div>
<div class="paragraph"><p>Inside the REPL, Control+D will exit. The special variable <tt>_</tt> (underscore) contains the
result of the last expression.</p></div>
<div class="paragraph"><p>The library is called <tt>/repl.js</tt> and it can be used like this:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>include("/utils.js");
include("/tcp.js");
nconnections = 0;
createServer(function (c) {
error("Connection!");
nconnections += 1;
c.close();
}).listen(5000);
require("/repl.js").start("simple tcp server> ");</tt></pre>
</div></div>
</div>
<h2 id="_extension_api">Extension API</h2>
<div class="sectionbody">
<div class="paragraph"><p>External modules can be compiled and dynamically linked into Node.
Node is more or less glue between several C and C++ libraries:</p></div>
<div class="ulist"><ul>
<li>
<p>
V8 Javascript, a C++ library. Used for interfacing with Javascript:
creating objects, calling functions, etc. Documented mostly in the
<tt>v8.h</tt> header file (<tt>deps/v8/include/v8.h</tt> in the Node source tree).
</p>
</li>
<li>
<p>
libev, C event loop library. Anytime one needs to wait for a file
descriptor to become readable, wait for a timer, or wait for a signal to
received one will need to interface with libev. That is, if you perform
any I/O, libev will need to be used. Node uses the <tt>EV_DEFAULT</tt> event
loop. Documentation can be found <a href="http:/cvs.schmorp.de/libev/ev.html">here</a>.
</p>
</li>
<li>
<p>
libeio, C thread pool library. Used to execute blocking POSIX system
calls asynchronously. Mostly wrappers already exist for such calls, in
<tt>src/file.cc</tt> so you will probably not need to use it. If you do need it,
look at the header file <tt>deps/libeio/eio.h</tt>.
</p>
</li>
<li>
<p>
Internal Node libraries. Most importantly is the <tt>node::EventEmitter</tt>
class which you will likely want to derive from.
</p>
</li>
<li>
<p>
Others. Look in <tt>deps/</tt> for what else is available.
</p>
</li>
</ul></div>
<div class="paragraph"><p>Node statically compiles all its dependencies into the executable. When
compiling your module, you don’t need to worry about linking to any of these
libraries.</p></div>
<div class="paragraph"><p>Here is a sample Makefile taken from
<a href="http://github.com/ry/node_postgres">node_postgres</a>:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>binding.node: binding.o Makefile
gcc -shared -o binding.node binding.o \
-L`pg_config --libdir` -lpq
binding.o: binding.cc Makefile
gcc `node --cflags` -I`pg_config --includedir` \
binding.cc -c -o binding.o
clean:
rm -f binding.o binding.node
.PHONY: clean</tt></pre>
</div></div>
<div class="paragraph"><p>As you can see, the only thing your module needs to know about Node is the
CFLAGS that node was compiled with which are gotten from <tt>node --cflags</tt>
If you want to make a debug build, then use <tt>node_g --cflags</tt>. (<tt>node_g</tt> is
the debug build of node, which can built with <tt>configure --debug; make; make
install</tt>.)</p></div>
<div class="paragraph"><p>Node extension modules are dynamically linked libraries with a <tt>.node</tt>
extension. Node opens this file and looks for a function called <tt>init()</tt>
which must be of the form:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>extern "C" void init (Handle<Object> target)</tt></pre>
</div></div>
<div class="paragraph"><p>In this function you can create new javascript objects and attach them to
<tt>target</tt>. Here is a very simple module:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>extern "C" void
init (Handle<Object> target)
{
HandleScope scope;
target->Set(String::New("hello"), String::New("World"));
}</tt></pre>
</div></div>
<div class="paragraph"><p>Further documentation will come soon. For now see the source code of
<a href="http://github.com/ry/node_postgres">node_postgres</a>.</p></div>
</div>
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