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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
const lazy = XPCOMUtils.declareLazy({
ProxyService: {
service: "@mozilla.org/network/protocol-proxy-service;1",
iid: Ci.nsIProtocolProxyService,
},
});
const { TRANSPARENT_PROXY_RESOLVES_HOST } = Ci.nsIProxyInfo;
/**
* IPPChannelFilter is a class that implements the nsIProtocolProxyChannelFilter
* when active it will funnel all requests to its provided proxy.
*
* the connection can be stopped
*
*/
export class IPPChannelFilter {
/**
* Creates a new IPPChannelFilter that can connect to a proxy server.
*
* @param {string} authToken - a bearer token for the proxy server.
* @param {string} host - the host of the proxy server.
* @param {number} port - the port of the proxy server.
* @param {string} proxyType - "socks" or "http" or "https"
*/
static create(authToken = "", host = "", port = 433, proxyType = "https") {
const isolationkey = Math.random()
.toString(36)
.slice(2, 18)
.padEnd(16, "0");
const failOverTimeout = 10; // seconds
const proxyInfo = lazy.ProxyService.newProxyInfo(
proxyType,
host,
port,
authToken,
isolationkey,
TRANSPARENT_PROXY_RESOLVES_HOST,
failOverTimeout,
null // Failover proxy info
);
if (!proxyInfo) {
throw new Error("Failed to create proxy info");
}
return new IPPChannelFilter(proxyInfo);
}
constructor(proxyInfo) {
if (!proxyInfo) {
throw new Error("ProxyInfo is required for IPPChannelFilter");
}
Object.freeze(proxyInfo);
this.proxyInfo = proxyInfo;
}
/**
* This method (which is required by the nsIProtocolProxyService interface)
* is called to apply proxy filter rules for the given URI and proxy object
* (or list of proxy objects).
*
* @param {nsIChannel} channel The channel for which these proxy settings apply.
* @param {nsIProxyInfo} _defaultProxyInfo The proxy (or list of proxies) that
* would be used by default for the given URI. This may be null.
* @param {nsIProxyProtocolFilterResult} proxyFilter
*/
async applyFilter(channel, _defaultProxyInfo, proxyFilter) {
proxyFilter.onProxyFilterResult(this.proxyInfo);
// Notify observers that the channel is being proxied
this.#observers.forEach(observer => {
observer(channel);
});
}
/**
* Starts the Channel Filter, feeding all following Requests through the proxy.
*/
start() {
lazy.ProxyService.registerChannelFilter(
this /* nsIProtocolProxyChannelFilter aFilter */,
0 /* unsigned long aPosition */
);
this.#active = true;
}
/**
* Stops the Channel Filter, stopping all following Requests from being proxied.
*/
stop() {
lazy.ProxyService.unregisterChannelFilter(this);
this.#active = false;
this.#abort.abort();
}
/**
* Returns the isolation key of the proxy connection.
* All ProxyInfo objects related to this Connection will have the same isolation key.
*/
get isolationKey() {
return this.proxyInfo.connectionIsolationKey;
}
/**
* Returns an async generator that yields channels this Connection is proxying.
*
* This allows to introspect channels that are proxied, i.e
* to measure usage, or catch proxy errors.
*
* @returns {AsyncGenerator<nsIChannel>} An async generator that yields proxied channels.
*/
async *proxiedChannels() {
const stop = Promise.withResolvers();
this.#abort.signal.addEventListener(
"abort",
() => {
stop.reject();
},
{ once: true }
);
while (this.#active) {
const { promise, resolve } = Promise.withResolvers();
this.#observers.push(resolve);
try {
const result = await Promise.race([stop.promise, promise]);
this.#observers = this.#observers.filter(
observer => observer !== resolve
);
yield result;
} catch (error) {
// Stop iteration if the filter is stopped or aborted
return;
}
}
}
/**
* Returns true if this filter is active.
*/
get active() {
return this.#active;
}
#abort = new AbortController();
#observers = [];
#active = false;
}