<div id="pageData-name" class="pageData">Proxy Settings</div>

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<p id="classSummary">
Use the <code>chrome.experimental.proxysettings</code> module to manage Chrome's
proxy settings. This module is still experimental. For information on how to use
experimental APIs, see the <a href="experimental.html">chrome.experimental.*
  APIs</a> page.
</p>

<h2 id="manifest">Manifest</h2>
<p>You must declare the "proxy" permission
in the <a href="manifest.html">extension manifest</a>
to use the proxy settings API.
For example:</p>
<pre>{
  "name": "My extension",
  ...
  <b>"permissions": [
    "experimental", "proxy"
  ]</b>,
  ...
}</pre>

<h2 id="description">Objects and properties</h2>

<p>
Proxy settings are defined in a 
<a href="#type-ProxyConfig"><code>ProxyConfig</code></a> object. Depending on
Chrome's proxy settings, the settings may contain
<a href="#type-ProxyRules"><code>ProxyRules</code></a> or a <a
  href="#type-PacScript"><code>PacScript</code></a>.
</p>

<h3 id="proxy_modes">Proxy modes</h3>

<p>
A ProxyConfig object's <code>mode</code> attribute determines the overall
behavior of Chrome with regards to proxy usage. It can take the following
values:
<dl>
  <dt><code>direct</code></dt>
  <dd>In <code>direct</code> mode all connections are created directly, without
  any proxy involved. This mode allows no further parameters in the
  <code>ProxyConfig</code> object.</dd>

  <dt><code>auto_detect</code></dt>
  <dd>In <code>auto_detect</code> mode the proxy configuration is determined by
  a PAC script that can be downloaded at
  <a href="http://wpad/wpad.dat">http://wpad/wpad.dat</a>.
  This mode allows no further parameters in the <code>ProxyConfig</code>
  object.</dd>

  <dt><code>pac_script</code></dt>
  <dd>In <code>pac_script</code> mode the proxy configuration is determined by
  a PAC script that is either retrieved from the URL specified in the
  <a href="#type-PacScript"><code>PacScript</code></a> object or
  taken literally from the <code>data</code> element specified in the
  <a href="#type-PacScript"><code>PacScript</code></a> object.
  Besides this, this mode allows no further parameters in the
  <code>ProxyConfig</code> object.</dd>

  <dt><code>fixed_servers</code></dt>
  <dd>In <code>fixed_servers</code> mode the proxy configuration is codified in
  a <a href="#type-ProxyRules><code>ProxyRules"><code>ProxyRules</code></a>
  object. Its structure is described in <a href="#proxy_rules">Proxy rules</a>.
  Besides this, the <code>fixed_servers</code> mode allows no further parameters
  in the <code>ProxyConfig</code> object.</dd>

  <dt><code>system</code></dt>
  <dd>In <code>system</code> mode the proxy configuration is taken from the
  operating system. This mode allows no further parameters in the
  <code>ProxyConfig</code> object. Note that the <code>system</code> mode is
  different from setting no proxy configuration. In the latter case, Chrome
  falls back to the system settings only if no command-line options influence
  the proxy configuration.</dd>
</dl>
</p>

<h3 id="proxy_rules">Proxy rules</h3>

<p>
The <a href="#type-ProxyRules"><code>ProxyRules</code></a> object can contain
either a <code>singleProxy</code> attribute or a subset of
<code>proxyForHttp</code>, <code>proxyForHttps</code>, <code>proxyForFtp</code>,
and <code>fallbackProxy</code>.
</p>

<p>
In the first case, HTTP, HTTPS and FTP traffic is proxied through the specified
proxy server. Other traffic is sent directly. In the latter case the behavior is
slightly more subtle: If a proxy server is configured for the HTTP, HTTPS or FTP
protocol, the respective traffic is proxied through the specified server. If no
such proxy server is specified or traffic uses a different protocol than HTTP,
HTTPS or FTP, the <code>fallbackProxy</code> is used. If no
<code>fallbackProxy</code> is specified, traffic is sent directly without a
proxy server.
</p>

<h3 id="proxy_server_objects">Proxy server objects</h3>

<p>
A proxy server is configured in a
<a href="#type-ProxyServer"><code>ProxyServer</code></a> object. The connection
to the proxy server (defined by the <code>host</code> attribute) uses the
protocol defined in the <code>scheme</code> attribute. If no <code>scheme</code>
is specified, the proxy connection defaults to <code>http</code>.
</p>

<p>
If no <code>port</code> is defined in a
<a href="#type-ProxyServer"><code>ProxyServer</code></a> object, the port is
derived from the scheme. The default ports are:
<table>
  <tr><th>Scheme</th><th>Port</th></tr>
  <tr><td>http</td><td>80</td></tr>
  <tr><td>https</td><td>443</td></tr>
  <tr><td>socks4</td><td>1080</td></tr>
  <tr><td>socks5</td><td>1080</td></tr>
</table>
</p>

<h3 id="bypass_list">Bypass list</h3>

<p>
Individual servers may be excluded from being proxied with the
<code>bypassList</code>. This list may contain the following entries:
<dl>
  <dt><code>[<em>&lt;scheme&gt;</em>://]<em>&lt;host-pattern&gt;</em>[:<em>&lt;port&gt;</em>]</code></dt>
  <dd>Match all hostnames that match the pattern <em>&lt;host-pattern&gt;</em>.<br>
  Examples: <code>"foobar.com", "*foobar.com", "*.foobar.com", "*foobar.com:99",
    "https://x.*.y.com:99"</code></dd>

  <dt><code>[<em>&lt;scheme&gt;</em>://]<em>&lt;ip-literal&gt;</em>[:<em>&lt;port&gt;</em>]</code></dt>
  <dd>Match URLs that are IP address literals.<br>
  Conceptually this is the similar to the first case, but with special cases
  to handle IP literal canonicalization. For example, matching
  on "[0:0:0::1]" is the same as matching on "[::1]" because
  the IPv6 canonicalization is done internally.<br>
  Examples: <code>"127.0.1", "[0:0::1]", "[::1]", "http://[::1]:99"</code></dd>

  <dt><code><em>&lt;ip-literal&gt;</em>/<em>&lt;prefix-length-in-bits&gt;</em></code></dt>
  <dd>Match any URL containing an IP literal within the given range. The IP 
  range is specified using CIDR notation.<br>
  Examples: <code>"192.168.1.1/16", "fefe:13::abc/33"</code></dd>

  <dt><code>&lt;local&gt;</code></dt>
  <dd>Match local addresses. An address is local if the host is "127.0.0.1",
  "::1", or "localhost".<br>
  Example: <code>"&lt;local&gt;"</code></dd>
</dl>


<h2 id="precedence">Precedence</h2>

<p>
Chrome manages settings on different layers. The following list describes the
layers that may influence the effective proxy settings, in increasing order of
precedence.
<ol>
  <li>System settings provided by the operating system</li>
  <li>Command line parameters</li>
  <li>Preferences set by extensions</li>
  <li>Policies</li>
</ol>
</p>

<p>
As the list implies, policies might overrule any changes that you specify with
the proxy settings API.
</p>

<p>
Chrome allows using different proxy settings for regular windows and incognito
windows. The following example illustrates the behavior. Assume that no policy
overrides the proxy settings and that an extension can set proxy settings for
regular windows <b>(R)</b> and proxy settings for incognito windows <b>(I)</b>.
</p>

<p>
<ul>
  <li>If only <b>(R)</b> is set, these settings are effective for both regular
  and incognito windows.</li>
  <li>If only <b>(I)</b> is set, these settings are effective for only incognito
  windows. Regular windows use the proxy settings determined by the lower layers
  (command-line options and system settings).</li>
  <li>If both <b>(R)</b> and <b>(I)</b> are set, the respective settings are
  used for regular and incognito windows.</li>
</ul>
</p>

<p>
If two extensions want to set proxy settings, the extension installed last takes
precedence over the other extensions. If the extension installed last sets only
<b>(I)</b>, the settings of regular windows can be defined by more recently
installed extensions.
</p>



<h2 id="overview-examples">Examples</h2>

<p>
The following code sets a SOCKS 5 proxy for HTTP connections to all servers but
foobar.com and uses direct connections for all other protocols. The settings
apply to regular and incognito windows.
</p>

<pre>
var config = {
  mode: "fixed_servers",
  rules: {
    httpProxy: {
      scheme: "socks5",
      host: "1.2.3.4"
    },
    bypassList: ["foobar.com"]
  }
};
chrome.experimental.proxy.settings.set(
    {'value': config, 'incognito': false},
    function() {});
</pre>

<p>
The following code sets a custom pac script.
</p>

<pre>
var config = {
  mode: "pac_script",
  pacScript: {
    data: "function FindProxyForURL(url, host) {\n" +
          "  if (host == 'foobar.com')\n" +
          "    return 'PROXY blackhole:80';\n" +
          "  return 'DIRECT';\n" +
          "}"
  }
};
chrome.experimental.proxy.settings.set(
    {'value': config, 'incognito': false},
    function() {});
</pre>

<p>
The next snippet queries the current proxy settings.
</p>

<pre>
chrome.experimental.proxy.settings.get(
    {'incognito': false},
    function(config) {console.log(JSON.stringify(config));});
</pre>

<p>
Note that the <code>value</code> object passed to <code>set()</code> is not
identical to the <code>value</code> object passed to callback function of
<code>get()</code>. The latter will contain a <code>rules.httpProxy.port</code>
element.
</p>

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