ai-agent-deep-dive/extracted-source/node_modules/@anthropic-ai/sandbox-runtime/dist/sandbox/http-proxy.js

import { Agent, createServer } from 'node:http';
import { request as httpRequest } from 'node:http';
import { request as httpsRequest } from 'node:https';
import { connect } from 'node:net';
import { URL } from 'node:url';
import { logForDebugging } from '../utils/debug.js';
export function createHttpProxyServer(options) {
    const server = createServer();
    // Handle CONNECT requests for HTTPS traffic
    server.on('connect', async (req, socket) => {
        // Attach error handler immediately to prevent unhandled errors
        socket.on('error', err => {
            logForDebugging(`Client socket error: ${err.message}`, { level: 'error' });
        });
        try {
            const [hostname, portStr] = req.url.split(':');
            const port = portStr === undefined ? undefined : parseInt(portStr, 10);
            if (!hostname || !port) {
                logForDebugging(`Invalid CONNECT request: ${req.url}`, {
                    level: 'error',
                });
                socket.end('HTTP/1.1 400 Bad Request\r\n\r\n');
                return;
            }
            const allowed = await options.filter(port, hostname, socket);
            if (!allowed) {
                logForDebugging(`Connection blocked to ${hostname}:${port}`, {
                    level: 'error',
                });
                socket.end('HTTP/1.1 403 Forbidden\r\n' +
                    'Content-Type: text/plain\r\n' +
                    'X-Proxy-Error: blocked-by-allowlist\r\n' +
                    '\r\n' +
                    'Connection blocked by network allowlist');
                return;
            }
            // Check if this host should be routed through a MITM proxy
            const mitmSocketPath = options.getMitmSocketPath?.(hostname);
            if (mitmSocketPath) {
                // Route through MITM proxy via Unix socket
                logForDebugging(`Routing CONNECT ${hostname}:${port} through MITM proxy at ${mitmSocketPath}`);
                const mitmSocket = connect({ path: mitmSocketPath }, () => {
                    // Send CONNECT request to the MITM proxy
                    mitmSocket.write(`CONNECT ${hostname}:${port} HTTP/1.1\r\n` +
                        `Host: ${hostname}:${port}\r\n` +
                        '\r\n');
                });
                // Buffer to accumulate the MITM proxy's response
                let responseBuffer = '';
                const onMitmData = (chunk) => {
                    responseBuffer += chunk.toString();
                    // Check if we've received the full HTTP response headers
                    const headerEndIndex = responseBuffer.indexOf('\r\n\r\n');
                    if (headerEndIndex !== -1) {
                        // Remove data listener, we're done parsing the response
                        mitmSocket.removeListener('data', onMitmData);
                        // Check if MITM proxy accepted the connection
                        const statusLine = responseBuffer.substring(0, responseBuffer.indexOf('\r\n'));
                        if (statusLine.includes(' 200 ')) {
                            // Connection established, now pipe data between client and MITM
                            socket.write('HTTP/1.1 200 Connection Established\r\n\r\n');
                            // If there's any data after the headers, write it to the client
                            const remainingData = responseBuffer.substring(headerEndIndex + 4);
                            if (remainingData.length > 0) {
                                socket.write(remainingData);
                            }
                            mitmSocket.pipe(socket);
                            socket.pipe(mitmSocket);
                        }
                        else {
                            logForDebugging(`MITM proxy rejected CONNECT: ${statusLine}`, {
                                level: 'error',
                            });
                            socket.end('HTTP/1.1 502 Bad Gateway\r\n\r\n');
                            mitmSocket.destroy();
                        }
                    }
                };
                mitmSocket.on('data', onMitmData);
                mitmSocket.on('error', err => {
                    logForDebugging(`MITM proxy connection failed: ${err.message}`, {
                        level: 'error',
                    });
                    socket.end('HTTP/1.1 502 Bad Gateway\r\n\r\n');
                });
                socket.on('error', err => {
                    logForDebugging(`Client socket error: ${err.message}`, {
                        level: 'error',
                    });
                    mitmSocket.destroy();
                });
                socket.on('end', () => mitmSocket.end());
                mitmSocket.on('end', () => socket.end());
            }
            else {
                // Direct connection (original behavior)
                const serverSocket = connect(port, hostname, () => {
                    socket.write('HTTP/1.1 200 Connection Established\r\n\r\n');
                    serverSocket.pipe(socket);
                    socket.pipe(serverSocket);
                });
                serverSocket.on('error', err => {
                    logForDebugging(`CONNECT tunnel failed: ${err.message}`, {
                        level: 'error',
                    });
                    socket.end('HTTP/1.1 502 Bad Gateway\r\n\r\n');
                });
                socket.on('error', err => {
                    logForDebugging(`Client socket error: ${err.message}`, {
                        level: 'error',
                    });
                    serverSocket.destroy();
                });
                socket.on('end', () => serverSocket.end());
                serverSocket.on('end', () => socket.end());
            }
        }
        catch (err) {
            logForDebugging(`Error handling CONNECT: ${err}`, { level: 'error' });
            socket.end('HTTP/1.1 500 Internal Server Error\r\n\r\n');
        }
    });
    // Handle regular HTTP requests
    server.on('request', async (req, res) => {
        try {
            const url = new URL(req.url);
            const hostname = url.hostname;
            const port = url.port
                ? parseInt(url.port, 10)
                : url.protocol === 'https:'
                    ? 443
                    : 80;
            const allowed = await options.filter(port, hostname, req.socket);
            if (!allowed) {
                logForDebugging(`HTTP request blocked to ${hostname}:${port}`, {
                    level: 'error',
                });
                res.writeHead(403, {
                    'Content-Type': 'text/plain',
                    'X-Proxy-Error': 'blocked-by-allowlist',
                });
                res.end('Connection blocked by network allowlist');
                return;
            }
            // Check if this host should be routed through a MITM proxy
            const mitmSocketPath = options.getMitmSocketPath?.(hostname);
            if (mitmSocketPath) {
                // Route through MITM proxy via Unix socket
                // Use an agent that connects via the Unix socket
                logForDebugging(`Routing HTTP ${req.method} ${hostname}:${port} through MITM proxy at ${mitmSocketPath}`);
                const mitmAgent = new Agent({
                    // @ts-expect-error - socketPath is valid but not in types
                    socketPath: mitmSocketPath,
                });
                // Send request to MITM proxy with full URL (proxy-style request)
                const proxyReq = httpRequest({
                    agent: mitmAgent,
                    // For proxy requests, path should be the full URL
                    path: req.url,
                    method: req.method,
                    headers: {
                        ...req.headers,
                        host: url.host,
                    },
                }, proxyRes => {
                    res.writeHead(proxyRes.statusCode, proxyRes.headers);
                    proxyRes.pipe(res);
                });
                proxyReq.on('error', err => {
                    logForDebugging(`MITM proxy request failed: ${err.message}`, {
                        level: 'error',
                    });
                    if (!res.headersSent) {
                        res.writeHead(502, { 'Content-Type': 'text/plain' });
                        res.end('Bad Gateway');
                    }
                });
                req.pipe(proxyReq);
            }
            else {
                // Direct request (original behavior)
                // Choose http or https module
                const requestFn = url.protocol === 'https:' ? httpsRequest : httpRequest;
                const proxyReq = requestFn({
                    hostname,
                    port,
                    path: url.pathname + url.search,
                    method: req.method,
                    headers: {
                        ...req.headers,
                        host: url.host,
                    },
                }, proxyRes => {
                    res.writeHead(proxyRes.statusCode, proxyRes.headers);
                    proxyRes.pipe(res);
                });
                proxyReq.on('error', err => {
                    logForDebugging(`Proxy request failed: ${err.message}`, {
                        level: 'error',
                    });
                    if (!res.headersSent) {
                        res.writeHead(502, { 'Content-Type': 'text/plain' });
                        res.end('Bad Gateway');
                    }
                });
                req.pipe(proxyReq);
            }
        }
        catch (err) {
            logForDebugging(`Error handling HTTP request: ${err}`, { level: 'error' });
            res.writeHead(500, { 'Content-Type': 'text/plain' });
            res.end('Internal Server Error');
        }
    });
    return server;
}
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