Add HTTP/HTTPS proxy configuration and environment variable support (#506)

src/services/mcpService.ts

@@ -14,6 +14,7 @@ import {
   StreamableHTTPClientTransport,
   StreamableHTTPClientTransportOptions,
 } from '@modelcontextprotocol/sdk/client/streamableHttp.js';
+import { createFetchWithProxy, getProxyConfigFromEnv } from './proxy.js';
 import { ServerInfo, ServerConfig, Tool } from '../types/index.js';
 import { expandEnvVars, replaceEnvVars, getNameSeparator } from '../config/index.js';
 import config from '../config/index.js';
@@ -134,6 +135,10 @@ export const cleanupAllServers = (): void => {
 // Helper function to create transport based on server configuration
 export const createTransportFromConfig = async (name: string, conf: ServerConfig): Promise<any> => {
   let transport;
+  const env: Record<string, string> = {
+    ...(process.env as Record<string, string>),
+    ...replaceEnvVars(conf.env || {}),
+  };
 
   if (conf.type === 'streamable-http') {
     const options: StreamableHTTPClientTransportOptions = {};
@@ -152,6 +157,8 @@ export const createTransportFromConfig = async (name: string, conf: ServerConfig
       console.log(`OAuth provider configured for server: ${name}`);
     }
 
+    options.fetch = createFetchWithProxy(getProxyConfigFromEnv(env));
+
     transport = new StreamableHTTPClientTransport(new URL(conf.url || ''), options);
   } else if (conf.url) {
     // SSE transport
@@ -174,13 +181,11 @@ export const createTransportFromConfig = async (name: string, conf: ServerConfig
       console.log(`OAuth provider configured for server: ${name}`);
     }
 
+    options.fetch = createFetchWithProxy(getProxyConfigFromEnv(env));
+
     transport = new SSEClientTransport(new URL(conf.url), options);
   } else if (conf.command && conf.args) {
     // Stdio transport
-    const env: Record<string, string> = {
-      ...(process.env as Record<string, string>),
-      ...replaceEnvVars(conf.env || {}),
-    };
     env['PATH'] = expandEnvVars(process.env.PATH as string) || '';
 
     const systemConfigDao = getSystemConfigDao();

src/services/proxy.ts

@@ -0,0 +1,167 @@
+/**
+ * HTTP/HTTPS proxy configuration utilities for MCP client transports.
+ *
+ * This module provides utilities to configure HTTP and HTTPS proxies when
+ * connecting to MCP servers. Proxies are configured by providing a custom
+ * fetch implementation that uses Node.js http/https agents with proxy support.
+ *
+ */
+
+import { FetchLike } from '@modelcontextprotocol/sdk/shared/transport.js';
+
+/**
+ * Configuration options for HTTP/HTTPS proxy settings.
+ */
+export interface ProxyConfig {
+  /**
+   * HTTP proxy URL (e.g., 'http://proxy.example.com:8080')
+   * Can include authentication: 'http://user:pass@proxy.example.com:8080'
+   */
+  httpProxy?: string;
+
+  /**
+   * HTTPS proxy URL (e.g., 'https://proxy.example.com:8443')
+   * Can include authentication: 'https://user:pass@proxy.example.com:8443'
+   */
+  httpsProxy?: string;
+
+  /**
+   * Comma-separated list of hosts that should bypass the proxy
+   * (e.g., 'localhost,127.0.0.1,.example.com')
+   */
+  noProxy?: string;
+}
+
+/**
+ * Creates a fetch function that uses the specified proxy configuration.
+ *
+ * This function returns a fetch implementation that routes requests through
+ * the configured HTTP/HTTPS proxies using undici's ProxyAgent.
+ *
+ * Note: This function requires the 'undici' package to be installed.
+ * Install it with: npm install undici
+ *
+ * @param config - Proxy configuration options
+ * @returns A fetch-compatible function configured to use the specified proxies
+ *
+ */
+export function createFetchWithProxy(config: ProxyConfig): FetchLike {
+  // If no proxy is configured, return the default fetch
+  if (!config.httpProxy && !config.httpsProxy) {
+    return fetch;
+  }
+
+  // Parse no_proxy list
+  const noProxyList = parseNoProxy(config.noProxy);
+
+  return async (url: string | URL, init?: RequestInit): Promise<Response> => {
+    const targetUrl = typeof url === 'string' ? new URL(url) : url;
+
+    // Check if host should bypass proxy
+    if (shouldBypassProxy(targetUrl.hostname, noProxyList)) {
+      return fetch(url, init);
+    }
+
+    // Determine which proxy to use based on protocol
+    const proxyUrl = targetUrl.protocol === 'https:' ? config.httpsProxy : config.httpProxy;
+
+    if (!proxyUrl) {
+      // No proxy configured for this protocol
+      return fetch(url, init);
+    }
+
+    // Use undici for proxy support if available
+    try {
+      // Dynamic import - undici is an optional peer dependency
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      const undici = await import('undici' as any);
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      const ProxyAgent = (undici as any).ProxyAgent;
+      const dispatcher = new ProxyAgent(proxyUrl);
+
+      return fetch(url, {
+        ...init,
+        // @ts-expect-error - dispatcher is undici-specific
+        dispatcher,
+      });
+    } catch (error) {
+      // undici not available - throw error requiring installation
+      throw new Error(
+        'Proxy support requires the "undici" package. ' +
+          'Install it with: npm install undici\n' +
+          `Original error: ${error instanceof Error ? error.message : String(error)}`,
+      );
+    }
+  };
+}
+
+/**
+ * Parses a NO_PROXY environment variable value into a list of patterns.
+ */
+function parseNoProxy(noProxy?: string): string[] {
+  if (!noProxy) {
+    return [];
+  }
+
+  return noProxy
+    .split(',')
+    .map((item) => item.trim())
+    .filter((item) => item.length > 0);
+}
+
+/**
+ * Checks if a hostname should bypass the proxy based on NO_PROXY patterns.
+ */
+function shouldBypassProxy(hostname: string, noProxyList: string[]): boolean {
+  if (noProxyList.length === 0) {
+    return false;
+  }
+
+  const hostnameLower = hostname.toLowerCase();
+
+  for (const pattern of noProxyList) {
+    const patternLower = pattern.toLowerCase();
+
+    // Exact match
+    if (hostnameLower === patternLower) {
+      return true;
+    }
+
+    // Domain suffix match (e.g., .example.com matches sub.example.com)
+    if (patternLower.startsWith('.') && hostnameLower.endsWith(patternLower)) {
+      return true;
+    }
+
+    // Domain suffix match without leading dot
+    if (!patternLower.startsWith('.') && hostnameLower.endsWith('.' + patternLower)) {
+      return true;
+    }
+
+    // Special case: "*" matches everything
+    if (patternLower === '*') {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+/**
+ * Creates a ProxyConfig from environment variables.
+ *
+ * This function reads standard proxy environment variables:
+ * - HTTP_PROXY, http_proxy
+ * - HTTPS_PROXY, https_proxy
+ * - NO_PROXY, no_proxy
+ *
+ * Lowercase versions take precedence over uppercase versions.
+ *
+ * @returns A ProxyConfig object populated from environment variables
+ */
+export function getProxyConfigFromEnv(env: Record<string, string>): ProxyConfig {
+  return {
+    httpProxy: env.http_proxy || env.HTTP_PROXY,
+    httpsProxy: env.https_proxy || env.HTTPS_PROXY,
+    noProxy: env.no_proxy || env.NO_PROXY,
+  };
+}