Revision 797271 of system/child_process

Revision slug: Mozilla/Add-ons/SDK/Low-Level_APIs/system_child_process
Revision title: system/child_process
Revision id: 797271
Created: May 4, 2015, 9:51:44 AM
Creator: wbamberg
Is current revision? No
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Revision Content

Experimental

An implementation of the node.js child_process API.

This module enables you to execute a child program in a new process. Since it emulates the node.js child_process API, it's not documented separately here. However, there are a few differences to be aware of:

you need to require() the module using require("sdk/system/child_process")
fork() is not supported
gid and uid are not supported
in node.js, spawn() and exec() inherit the environment variables from the parent process, by default. The SDK versions don't: so when you specify a command you must pass in a complete path to the command or use the env option to set up the child process environment.

Here's an example that adapts the example in node's documentation for spawn():

var child_process = require("sdk/system/child_process");

var ls = child_process.spawn('/bin/ls', ['-lh', '/usr']);

ls.stdout.on('data', function (data) {
  console.log('stdout: ' + data);
});

ls.stderr.on('data', function (data) {
  console.log('stderr: ' + data);
});

ls.on('close', function (code) {
  console.log('child process exited with code ' + code);
});

Revision Source

<div class="note">
<p>Experimental</p>
</div>

<p><span class="seoSummary">An implementation of the <a href="https://nodejs.org/api/child_process.html">node.js <code>child_process</code> API</a>.</span></p>

<p>This module enables you to execute a child program in a new process. Since it emulates the node.js <code>child_process</code> API, it's not documented separately here. However, there are a few differences to be aware of:</p>

<ul>
 <li>you need to require() the module using <code>require("sdk/system/child_process")</code></li>
 <li><code>fork()</code> is not supported</li>
 <li><code>gid</code> and <code>uid</code> are not supported</li>
 <li>in node.js, <code>spawn()</code> and <code>exec()</code> inherit the environment variables from the parent process, by default. The SDK versions don't: so when you specify a command you must pass in a complete path to the command or use the <code>env</code> option to set up the child process environment.</li>
</ul>

<p>Here's an example that adapts the example in node's documentation for <a href="https://nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options"><code>spawn()</code></a>:</p>

<pre class="brush: js">
var child_process = require("sdk/system/child_process");

var ls = child_process.spawn('/bin/ls', ['-lh', '/usr']);

ls.stdout.on('data', function (data) {
  console.log('stdout: ' + data);
});

ls.stderr.on('data', function (data) {
  console.log('stderr: ' + data);
});

ls.on('close', function (code) {
  console.log('child process exited with code ' + code);
});</pre>

<p>&nbsp;</p>

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