pac-proxy-agent
Version:
A PAC file proxy `http.Agent` implementation for HTTP
238 lines • 9.93 kB
JavaScript
;
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var __importStar = (this && this.__importStar) || function (mod) {
if (mod && mod.__esModule) return mod;
var result = {};
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var __importDefault = (this && this.__importDefault) || function (mod) {
return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.PacProxyAgent = void 0;
const net = __importStar(require("net"));
const tls = __importStar(require("tls"));
const crypto = __importStar(require("crypto"));
const events_1 = require("events");
const debug_1 = __importDefault(require("debug"));
const url_1 = require("url");
const agent_base_1 = require("agent-base");
const get_uri_1 = require("get-uri");
const pac_resolver_1 = require("pac-resolver");
const quickjs_emscripten_1 = require("@tootallnate/quickjs-emscripten");
const debug = (0, debug_1.default)('pac-proxy-agent');
const setServernameFromNonIpHost = (options) => {
if (options.servername === undefined &&
options.host &&
!net.isIP(options.host)) {
return {
...options,
servername: options.host,
};
}
return options;
};
/**
* The `PacProxyAgent` class.
*
* A few different "protocol" modes are supported (supported protocols are
* backed by the `get-uri` module):
*
* - "pac+data", "data" - refers to an embedded "data:" URI
* - "pac+file", "file" - refers to a local file
* - "pac+ftp", "ftp" - refers to a file located on an FTP server
* - "pac+http", "http" - refers to an HTTP endpoint
* - "pac+https", "https" - refers to an HTTPS endpoint
*/
class PacProxyAgent extends agent_base_1.Agent {
constructor(uri, opts) {
super(opts);
this.clearResolverPromise = () => {
this.resolverPromise = undefined;
};
// Strip the "pac+" prefix
const uriStr = typeof uri === 'string' ? uri : uri.href;
this.uri = new url_1.URL(uriStr.replace(/^pac\+/i, ''));
debug('Creating PacProxyAgent with URI %o', this.uri.href);
// @ts-expect-error Not sure why TS is complaining here…
this.opts = { ...opts };
this.cache = undefined;
this.resolver = undefined;
this.resolverHash = '';
this.resolverPromise = undefined;
// For `PacResolver`
if (!this.opts.filename) {
this.opts.filename = this.uri.href;
}
}
/**
* Loads the PAC proxy file from the source if necessary, and returns
* a generated `FindProxyForURL()` resolver function to use.
*/
getResolver() {
if (!this.resolverPromise) {
this.resolverPromise = this.loadResolver();
this.resolverPromise.then(this.clearResolverPromise, this.clearResolverPromise);
}
return this.resolverPromise;
}
async loadResolver() {
try {
// (Re)load the contents of the PAC file URI
const [qjs, code] = await Promise.all([
(0, quickjs_emscripten_1.getQuickJS)(),
this.loadPacFile(),
]);
// Create a sha1 hash of the JS code
const hash = crypto.createHash('sha1').update(code).digest('hex');
if (this.resolver && this.resolverHash === hash) {
debug('Same sha1 hash for code - contents have not changed, reusing previous proxy resolver');
return this.resolver;
}
// Cache the resolver
debug('Creating new proxy resolver instance');
this.resolver = (0, pac_resolver_1.createPacResolver)(qjs, code, this.opts);
// Store that sha1 hash for future comparison purposes
this.resolverHash = hash;
return this.resolver;
}
catch (err) {
if (this.resolver &&
err.code === 'ENOTMODIFIED') {
debug('Got ENOTMODIFIED response, reusing previous proxy resolver');
return this.resolver;
}
throw err;
}
}
/**
* Loads the contents of the PAC proxy file.
*
* @api private
*/
async loadPacFile() {
debug('Loading PAC file: %o', this.uri);
const rs = await (0, get_uri_1.getUri)(this.uri, { ...this.opts, cache: this.cache });
debug('Got `Readable` instance for URI');
this.cache = rs;
const buf = await (0, agent_base_1.toBuffer)(rs);
debug('Read %o byte PAC file from URI', buf.length);
return buf.toString('utf8');
}
/**
* Called when the node-core HTTP client library is creating a new HTTP request.
*/
async connect(req, opts) {
const { secureEndpoint } = opts;
const isWebSocket = req.getHeader('upgrade') === 'websocket';
// First, get a generated `FindProxyForURL()` function,
// either cached or retrieved from the source
const resolver = await this.getResolver();
// Calculate the `url` parameter
const protocol = secureEndpoint ? 'https:' : 'http:';
const host = opts.host && net.isIPv6(opts.host) ? `[${opts.host}]` : opts.host;
const defaultPort = secureEndpoint ? 443 : 80;
const url = Object.assign(new url_1.URL(req.path, `${protocol}//${host}`), defaultPort ? undefined : { port: opts.port });
debug('url: %s', url);
let result = await resolver(url);
// Default to "DIRECT" if a falsey value was returned (or nothing)
if (!result) {
result = 'DIRECT';
}
const proxies = String(result)
.trim()
.split(/\s*;\s*/g)
.filter(Boolean);
if (this.opts.fallbackToDirect && !proxies.includes('DIRECT')) {
proxies.push('DIRECT');
}
for (const proxy of proxies) {
let agent = null;
let socket = null;
const [type, target] = proxy.split(/\s+/);
debug('Attempting to use proxy: %o', proxy);
if (type === 'DIRECT') {
// Direct connection to the destination endpoint
if (secureEndpoint) {
socket = tls.connect(setServernameFromNonIpHost(opts));
}
else {
socket = net.connect(opts);
}
}
else if (type === 'SOCKS' || type === 'SOCKS5') {
// Use a SOCKSv5h proxy
const { SocksProxyAgent } = await Promise.resolve().then(() => __importStar(require('socks-proxy-agent')));
agent = new SocksProxyAgent(`socks://${target}`, this.opts);
}
else if (type === 'SOCKS4') {
// Use a SOCKSv4a proxy
const { SocksProxyAgent } = await Promise.resolve().then(() => __importStar(require('socks-proxy-agent')));
agent = new SocksProxyAgent(`socks4a://${target}`, this.opts);
}
else if (type === 'PROXY' ||
type === 'HTTP' ||
type === 'HTTPS') {
// Use an HTTP or HTTPS proxy
// http://dev.chromium.org/developers/design-documents/secure-web-proxy
const proxyURL = `${type === 'HTTPS' ? 'https' : 'http'}://${target}`;
if (secureEndpoint || isWebSocket) {
const { HttpsProxyAgent } = await Promise.resolve().then(() => __importStar(require('https-proxy-agent')));
agent = new HttpsProxyAgent(proxyURL, this.opts);
}
else {
const { HttpProxyAgent } = await Promise.resolve().then(() => __importStar(require('http-proxy-agent')));
agent = new HttpProxyAgent(proxyURL, this.opts);
}
}
try {
if (socket) {
// "DIRECT" connection, wait for connection confirmation
await (0, events_1.once)(socket, 'connect');
req.emit('proxy', { proxy, socket });
return socket;
}
if (agent) {
const s = await agent.connect(req, opts);
if (!(s instanceof net.Socket)) {
throw new Error('Expected a `net.Socket` to be returned from agent');
}
req.emit('proxy', { proxy, socket: s });
return s;
}
throw new Error(`Could not determine proxy type for: ${proxy}`);
}
catch (err) {
debug('Got error for proxy %o: %o', proxy, err);
req.emit('proxy', { proxy, error: err });
}
}
throw new Error(`Failed to establish a socket connection to proxies: ${JSON.stringify(proxies)}`);
}
}
PacProxyAgent.protocols = [
'pac+data',
'pac+file',
'pac+ftp',
'pac+http',
'pac+https',
];
exports.PacProxyAgent = PacProxyAgent;
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