moving things around now that /react is moving to use-mcp

src/proxy.ts

@@ -0,0 +1,101 @@
+#!/usr/bin/env node
+
+/**
+ * MCP Proxy with OAuth support
+ * A bidirectional proxy between a local STDIO MCP server and a remote SSE server with OAuth authentication.
+ *
+ * Run with: npx tsx proxy.ts https://example.remote/server [callback-port]
+ *
+ * If callback-port is not specified, an available port will be automatically selected.
+ */
+
+import { EventEmitter } from 'events'
+import { StdioServerTransport } from '@modelcontextprotocol/sdk/server/stdio.js'
+import { NodeOAuthClientProvider, setupOAuthCallbackServer, parseCommandLineArgs, setupSignalHandlers } from './shared'
+import { connectToRemoteServer, mcpProxy } from './lib/utils'
+
+/**
+ * Main function to run the proxy
+ */
+async function runProxy(serverUrl: string, callbackPort: number) {
+  // Set up event emitter for auth flow
+  const events = new EventEmitter()
+
+  // Create the OAuth client provider
+  const authProvider = new NodeOAuthClientProvider({
+    serverUrl,
+    callbackPort,
+    clientName: 'MCP CLI Proxy',
+  })
+
+  // Create the STDIO transport for local connections
+  const localTransport = new StdioServerTransport()
+
+  // Set up an HTTP server to handle OAuth callback
+  const { server, waitForAuthCode } = setupOAuthCallbackServer({
+    port: callbackPort,
+    path: '/oauth/callback',
+    events,
+  })
+
+  try {
+    // Connect to remote server with authentication
+    const remoteTransport = await connectToRemoteServer(serverUrl, authProvider, waitForAuthCode)
+
+    // Set up bidirectional proxy between local and remote transports
+    mcpProxy({
+      transportToClient: localTransport,
+      transportToServer: remoteTransport,
+    })
+
+    // Start the local STDIO server
+    await localTransport.start()
+    console.error('Local STDIO server running')
+    console.error('Proxy established successfully between local STDIO and remote SSE')
+    console.error('Press Ctrl+C to exit')
+
+    // Setup cleanup handler
+    const cleanup = async () => {
+      await remoteTransport.close()
+      await localTransport.close()
+      server.close()
+    }
+    setupSignalHandlers(cleanup)
+  } catch (error) {
+    console.error('Fatal error:', error)
+    if (error instanceof Error && error.message.includes('self-signed certificate in certificate chain')) {
+      console.error(`You may be behind a VPN!
+
+If you are behind a VPN, you can try setting the NODE_EXTRA_CA_CERTS environment variable to point
+to the CA certificate file. If using claude_desktop_config.json, this might look like:
+
+{
+  "mcpServers": {
+    "\${mcpServerName}": {
+      "command": "npx",
+      "args": [
+        "mcp-remote",
+        "https://remote.mcp.server/sse"
+      ],
+      "env": {
+        "NODE_EXTRA_CA_CERTS": "\${your CA certificate file path}.pem"
+      }
+    }
+  }
+}
+        `)
+    }
+    server.close()
+    process.exit(1)
+  }
+}
+
+// Parse command-line arguments and run the proxy
+parseCommandLineArgs(process.argv.slice(2), 3334, 'Usage: npx tsx proxy.ts <https://server-url> [callback-port]')
+  .then(({ serverUrl, callbackPort }) => {
+    return runProxy(serverUrl, callbackPort)
+  })
+  .catch((error) => {
+    console.error('Fatal error:', error)
+    process.exit(1)
+  })