Google Chrome Extensions

chrome.proxy

Use the chrome.proxy module to manage Chrome's proxy settings. This module relies on the ChromeSetting prototype of the type API for getting and setting the proxy configuration.

Manifest

You must declare the "proxy" permission in the extension manifest to use the proxy settings API. For example:

{
  "name": "My extension",
  ...
  "permissions": [
    "proxy"
  ],
  ...
}

Objects and properties

Proxy settings are defined in a ProxyConfig object. Depending on Chrome's proxy settings, the settings may contain ProxyRules or a PacScript.

Proxy modes

A ProxyConfig object's mode attribute determines the overall behavior of Chrome with regards to proxy usage. It can take the following values:

direct
In direct mode all connections are created directly, without any proxy involved. This mode allows no further parameters in the ProxyConfig object.
auto_detect
In auto_detect mode the proxy configuration is determined by a PAC script that can be downloaded at http://wpad/wpad.dat. This mode allows no further parameters in the ProxyConfig object.
pac_script
In pac_script mode the proxy configuration is determined by a PAC script that is either retrieved from the URL specified in the PacScript object or taken literally from the data element specified in the PacScript object. Besides this, this mode allows no further parameters in the ProxyConfig object.
fixed_servers
In fixed_servers mode the proxy configuration is codified in a ProxyRules object. Its structure is described in Proxy rules. Besides this, the fixed_servers mode allows no further parameters in the ProxyConfig object.
system
In system mode the proxy configuration is taken from the operating system. This mode allows no further parameters in the ProxyConfig object. Note that the system 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.

Proxy rules

The ProxyRules object can contain either a singleProxy attribute or a subset of proxyForHttp, proxyForHttps, proxyForFtp, and fallbackProxy.

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 fallbackProxy is used. If no fallbackProxy is specified, traffic is sent directly without a proxy server.

Proxy server objects

A proxy server is configured in a ProxyServer object. The connection to the proxy server (defined by the host attribute) uses the protocol defined in the scheme attribute. If no scheme is specified, the proxy connection defaults to http.

If no port is defined in a ProxyServer object, the port is derived from the scheme. The default ports are:

SchemePort
http80
https443
socks41080
socks51080

Bypass list

Individual servers may be excluded from being proxied with the bypassList. This list may contain the following entries:

[<scheme>://]<host-pattern>[:<port>]
Match all hostnames that match the pattern <host-pattern>.
Examples: "foobar.com", "*foobar.com", "*.foobar.com", "*foobar.com:99", "https://x.*.y.com:99"
[<scheme>://]<ip-literal>[:<port>]
Match URLs that are IP address literals.
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.
Examples: "127.0.1", "[0:0::1]", "[::1]", "http://[::1]:99"
<ip-literal>/<prefix-length-in-bits>
Match any URL containing an IP literal within the given range. The IP range is specified using CIDR notation.
Examples: "192.168.1.1/16", "fefe:13::abc/33"
<local>
Match local addresses. An address is local if the host is "127.0.0.1", "::1", or "localhost".
Example: "<local>"

Examples

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, as incognito windows inherit settings from regular windows. Please also consult the Types API documentation.

var config = {
  mode: "fixed_servers",
  rules: {
    proxyForHttp: {
      scheme: "socks5",
      host: "1.2.3.4"
    },
    bypassList: ["foobar.com"]
  }
};
chrome.proxy.settings.set(
    {value: config, scope: 'regular'},
    function() {});

The following code sets a custom PAC script.

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.proxy.settings.set(
    {value: config, scope: 'regular'},
    function() {});

The next snippet queries the currently effective proxy settings. The effective proxy settings can be determined by another extension or by a policy. See the Types API documentation for details.

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

Note that the value object passed to set() is not identical to the value object passed to callback function of get(). The latter will contain a rules.proxyForHttp.port element.

API Reference: chrome.proxy

Types

ProxyServer

( object )
An object encapsulating a single proxy server's specification.

Properties of ProxyServer

scheme ( optional enumerated string ["http", "https", "socks4", "socks5"] )
The scheme (protocol) of the proxy server itself. Defaults to 'http'.
host ( string )
The URI of the proxy server. This must be an ASCII hostname (in Punycode format). IDNA is not supported, yet.
port ( optional integer )
The port of the proxy server. Defaults to a port that depends on the scheme.

ProxyRules

( object )
An object encapsulating the set of proxy rules for all protocols. Use either 'singleProxy' or (a subset of) 'proxyForHttp', 'proxyForHttps', 'proxyForFtp' and 'fallbackProxy'.

Properties of ProxyRules

singleProxy ( optional ProxyServer )
The proxy server to be used for all per-URL requests (that is http, https, and ftp).
proxyForHttp ( optional ProxyServer )
The proxy server to be used for HTTP requests.
proxyForHttps ( optional ProxyServer )
The proxy server to be used for HTTPS requests.
proxyForFtp ( optional ProxyServer )
The proxy server to be used for FTP requests.
fallbackProxy ( optional ProxyServer )
The proxy server to be used for everthing else or if any of the specific proxyFor... is not specified.
bypassList ( optional array of string )
List of servers to connect to without a proxy server.

PacScript

( object )
An object holding proxy auto-config information. Exactly one of the fields should be non-empty.

Properties of PacScript

url ( optional string )
URL of the PAC file to be used.
data ( optional string )
A PAC script.
mandatory ( optional boolean )
If true, an invalid PAC script will prevent the network stack from falling back to direct connections. Defaults to false.

ProxyConfig

( object )
An object encapsulating a complete proxy configuration.

Properties of ProxyConfig

rules ( optional ProxyRules )
The proxy rules describing this configuration. Use this for 'fixed_servers' mode.
pacScript ( optional PacScript )
The proxy auto-config (PAC) script for this configuration. Use this for 'pac_script' mode.
mode ( enumerated string ["direct", "auto_detect", "pac_script", "fixed_servers", "system"] )
'direct' = Never use a proxy
'auto_detect' = Auto detect proxy settings
'pac_script' = Use specified PAC script
'fixed_servers' = Manually specify proxy servers
'system' = Use system proxy settings

Properties

settings

chrome.proxy.settings
settings ( types.ChromeSetting )
Proxy settings to be used. The value of this setting is a ProxyConfig object.

Events

onProxyError

chrome.proxy.onProxyError.addListener(function(object details) {...});

Notifies about proxy errors.

Listener Parameters

details ( object )
fatal ( boolean )
If true, the error was fatal and the network transaction was aborted. Otherwise, a direct connection is used instead.
error ( string )
The error description.
details ( string )
Additional details about the error such as a JavaScript runtime error.

Sample Extensions that use chrome.proxy

  • Proxy Extension API Sample – Set Chrome-specific proxies; a demonstration of Chrome's Proxy API