[socks-proxy-agent] pass socket_options to SocksClient (#302)

Co-authored-by: Nathan Rajlich <n@n8.io>

.changeset/silver-pumas-drum.md

@@ -0,0 +1,5 @@
+---
+"socks-proxy-agent": patch
+---
+
+Pass `socket_options` to `SocksClient`

packages/socks-proxy-agent/src/index.ts

@@ -71,11 +71,15 @@ function parseSocksURL(url: URL): { lookup: boolean; proxy: SocksProxy } {
 	return { lookup, proxy };
 }
 
+type SocksSocketOptions = Omit<net.TcpNetConnectOpts, 'port' | 'host'>;
+
 export type SocksProxyAgentOptions = Omit<
 	SocksProxy,
 	// These come from the parsed URL
 	'ipaddress' | 'host' | 'port' | 'type' | 'userId' | 'password'
-> &
+> & {
+	socketOptions?: SocksSocketOptions;
+} &
 	http.AgentOptions;
 
 export class SocksProxyAgent extends Agent {
@@ -90,6 +94,7 @@ export class SocksProxyAgent extends Agent {
 	readonly shouldLookup: boolean;
 	readonly proxy: SocksProxy;
 	timeout: number | null;
+	socketOptions: SocksSocketOptions | null;
 
 	constructor(uri: string | URL, opts?: SocksProxyAgentOptions) {
 		super(opts);
@@ -100,6 +105,7 @@ export class SocksProxyAgent extends Agent {
 		this.shouldLookup = lookup;
 		this.proxy = proxy;
 		this.timeout = opts?.timeout ?? null;
+		this.socketOptions = opts?.socketOptions ?? null;
 	}
 
 	/**
@@ -141,6 +147,9 @@ export class SocksProxyAgent extends Agent {
 			},
 			command: 'connect',
 			timeout: timeout ?? undefined,
+			// @ts-expect-error the type supplied by socks for socket_options is wider
+			// than necessary since socks will always override the host and port
+			socket_options: this.socketOptions ?? undefined,
 		};
 
 		const cleanup = (tlsSocket?: tls.TLSSocket) => {

packages/socks-proxy-agent/test/test.ts

@@ -21,19 +21,26 @@ describe('SocksProxyAgent', () => {
 	// eslint-disable-next-line @typescript-eslint/no-explicit-any
 	let socksServer: any;
 	let socksServerUrl: URL;
+	let socksServerHost: string | null = null;
 
-	beforeAll(async () => {
+	beforeEach(async () => {
 		// setup SOCKS proxy server
 		// @ts-expect-error no types for `socksv5`
 		socksServer = socks.createServer(function (_info, accept) {
 			accept();
 		});
-		await listen(socksServer);
-		const port = socksServer.address().port;
-		socksServerUrl = new URL(`socks://127.0.0.1:${port}`);
+		await listen(socksServer, 0, socksServerHost ?? '127.0.0.1');
+		const { port, family, address } = socksServer.address();
+		socksServerUrl = new URL(
+			`socks://${family === 'IPv6' ? 'localhost' : address}:${port}`
+		);
 		socksServer.useAuth(socks.auth.None());
 	});
 
+	afterEach(() => {
+		socksServer.close();
+	});
+
 	beforeAll(async () => {
 		// setup target HTTP server
 		httpServer = http.createServer();
@@ -55,7 +62,6 @@ describe('SocksProxyAgent', () => {
 	});
 
 	afterAll(() => {
-		socksServer.close();
 		httpServer.close();
 		httpsServer.close();
 	});
@@ -90,6 +96,37 @@ describe('SocksProxyAgent', () => {
 		});
 	});
 
+	describe('ipv6 host', () => {
+		beforeAll(() => {
+			socksServerHost = '::1';
+		});
+		afterAll(() => {
+			socksServerHost = null;
+		});
+
+		it('should connect over ipv6 socket', async () => {
+			httpServer.once('request', (req, res) => res.end());
+
+			const res = await req(new URL('/foo', httpServerUrl), {
+				agent: new SocksProxyAgent(socksServerUrl, { socketOptions: { family: 6 } }),
+			});
+			assert(res);
+		});
+
+		it('should refuse connection over ipv4 socket', async () => {
+			let err: Error | undefined;
+			try {
+				await req(new URL('/foo', httpServerUrl), {
+					agent: new SocksProxyAgent(socksServerUrl, { socketOptions: { family: 4 } }),
+				});
+			} catch (_err) {
+				err = _err as Error;
+			}
+			assert(err);
+			assert.equal(err.message, `connect ECONNREFUSED 127.0.0.1:${socksServerUrl.port}`);
+		});
+	});
+
 	describe('"http" module', () => {
 		it('should work against an HTTP endpoint', async () => {
 			httpServer.once('request', function (req, res) {