PAC ファイルと拡張機能のバックグラウンドページ(やその他の権限つきページ、ポップアップページのようなもの)とでメッセージを交換できて、その手段はruntime.sendMessage() とruntime.onMessage。

PAC ファイルにメッセージを送るには、toProxyScript オプションをセットしなければなりません:

// background.js// Log any messages from the proxy.browser.runtime.onMessage.addListener((message, sender) => {  if (sender.url === browser.extension.getURL(proxyScriptURL)) {    console.log(message);  }});let messageToProxy = {  enabled: true,  foo: "A string",  bar: 1234,};browser.runtime.sendMessage(messageToProxy, { toProxyScript: true });

// pac.jsbrowser.runtime.onMessage.addListener((message) => {  if (message.enabled) {    browser.runtime.sendMessage("I'm enabled!");  }});

The basic PAC file syntax is described in thePAC documentation, but the implementation used by the proxy API differs from standard PAC design in several ways, which are described in this section.

The standardFindProxyForURL()returns a string. In Firefox 55 and 56, the PAC file used with the proxy API also returns a string. In Firefox 55only, you must pass an argument to the "DIRECT" return value, even though it doesn't need an argument.

From Firefox 57 onwards,FindProxyForURL() may still return a string, but may alternatively (and preferably) return an array of objects. Each object has the following properties:

type

String. This must be one of: "http"|"https|"socks4"|"socks"|"direct". "socks" refers to the SOCKS5 protocol.

host

String. Hostname for the proxy to use.

port

String. Port for the proxy.

username省略可

String. Username for the proxy. This is usable with "socks". For HTTP proxy authorizations, usewebRequest.onAuthRequired.

password省略可

String. Password for the proxy. This is usable with "socks". For HTTP proxy authorizations, usewebRequest.onAuthRequired.

proxyDNS省略可

Boolean. If true, the proxy server is used to resolve certain DNS queries (only usable with "socks4" and "socks"). Defaults tofalse.

failoverTimeout省略可

Integer. Number of seconds before timing out and trying the next proxy in the array. Defaults to 1.

例えば、:

const proxySpecification = [  {    type: "socks",    host: "foo.com",    port: 1080,    proxyDNS: true,    failoverTimeout: 5,  },  {    type: "socks",    host: "bar.com",    port: 1060,  },];

The first proxy in the array will be tried first. If it does not respond infailoverTimeout seconds, the next will be tried, until the end of the array is reached.

The global helper functions usually available for PAC files (isPlainHostName(),dnsDomainIs(), and so on) are not available.

Code running in the PAC file does not get access to:

• any DOM functions (例えば、window or any of its properties)
• any WebExtension APIs exceptruntime.sendMessage() andruntime.onMessage
• theconsole API - to log messages from a PAC, send a message to the background script:

//  pac.js// send the log message to the background scriptbrowser.runtime.sendMessage(`Proxy-blocker: blocked ${url}`);

// background-script.jsfunction handleMessage(message, sender) {  // only handle messages from the proxy script  if (sender.url != browser.extension.getURL(proxyScriptURL)) {    return;  }  console.log(message);}browser.runtime.onMessage.addListener(handleMessage);

proxy.register()

所与のプロキシースクリプトを登録する

proxy.unregister()

プロキシースクリプトの登録を取り消す。

proxy.onProxyError

プロキシースクリプト実行している際にシステムがエラーに遭遇した時に発火します。

• proxy-blocker