feat: sse transport (#57)

README.md

@@ -93,27 +93,19 @@ This mode is useful for background or batch operations.
 ### Running headed browser on Linux w/o DISPLAY
 
 When running headed browser on system w/o display or from worker processes of the IDEs,
-you can run Playwright in a client-server manner. You'll run the Playwright server
-from environment with the DISPLAY
+run the MCP server from environment with the DISPLAY and pass the `--port` flag to enable SSE transport.
 
-```sh
-npx playwright run-server
+```bash
+npx @playwright/mcp@latest --port 8931
 ```
 
-And then in MCP config, add following to the `env`:
+And then in MCP client config, set the `url` to the SSE endpoint:
 
 ```js
 {
   "mcpServers": {
     "playwright": {
-      "command": "npx",
-      "args": [
-        "@playwright/mcp@latest"
-      ],
-      "env": {
-        // Use the endpoint from the output of the server above.
-        "PLAYWRIGHT_WS_ENDPOINT": "ws://localhost:<port>/"
-      }
+      "url": "http://localhost:8931/sse"
     }
   }
 }

src/program.ts

@@ -14,17 +14,21 @@
  * limitations under the License.
  */
 
+import http from 'http';
 import fs from 'fs';
 import os from 'os';
 import path from 'path';
 
 import { program } from 'commander';
 import { StdioServerTransport } from '@modelcontextprotocol/sdk/server/stdio.js';
+import { SSEServerTransport } from '@modelcontextprotocol/sdk/server/sse.js';
+
 
 import { createServer } from './index';
 
 import type { Server } from '@modelcontextprotocol/sdk/server/index.js';
 import type { LaunchOptions } from 'playwright';
+import assert from 'assert';
 
 const packageJSON = require('../package.json');
 
@@ -34,6 +38,7 @@ program
     .option('--headless', 'Run browser in headless mode, headed by default')
     .option('--user-data-dir <path>', 'Path to the user data directory')
     .option('--vision', 'Run server that uses screenshots (Aria snapshots are used by default)')
+    .option('--port <port>', 'Port to listen on for SSE transport.')
     .action(async options => {
       const launchOptions: LaunchOptions = {
         headless: !!options.headless,
@@ -46,8 +51,66 @@ program
       });
       setupExitWatchdog(server);
 
-      const transport = new StdioServerTransport();
-      await server.connect(transport);
+      if (options.port) {
+        const sessions = new Map<string, SSEServerTransport>();
+        const httpServer = http.createServer(async (req, res) => {
+          if (req.method === 'POST') {
+            const host = req.headers.host ?? 'http://unknown';
+            const sessionId = new URL(host + req.url!).searchParams.get('sessionId');
+            if (!sessionId) {
+              res.statusCode = 400;
+              res.end('Missing sessionId');
+              return;
+            }
+            const transport = sessions.get(sessionId);
+            if (!transport) {
+              res.statusCode = 404;
+              res.end('Session not found');
+              return;
+            }
+
+            await transport.handlePostMessage(req, res);
+            return;
+          } else if (req.method === 'GET') {
+            const transport = new SSEServerTransport('/sse', res);
+            sessions.set(transport.sessionId, transport);
+            res.on('close', () => {
+              sessions.delete(transport.sessionId);
+            });
+            await server.connect(transport);
+            return;
+          } else {
+            res.statusCode = 405;
+            res.end('Method not allowed');
+          }
+        });
+        httpServer.listen(+options.port, () => {
+          const address = httpServer.address();
+          assert(address, 'Could not bind server socket');
+          let urlPrefixHumanReadable: string;
+          if (typeof address === 'string') {
+            urlPrefixHumanReadable = address;
+          } else {
+            const port = address.port;
+            let resolvedHost = address.family === 'IPv4' ? address.address : `[${address.address}]`;
+            if (resolvedHost === '0.0.0.0' || resolvedHost === '[::]')
+              resolvedHost = 'localhost';
+            urlPrefixHumanReadable = `http://${resolvedHost}:${port}`;
+          }
+          console.log(`Listening on ${urlPrefixHumanReadable}`);
+          console.log('Put this in your client config:');
+          console.log(JSON.stringify({
+            'mcpServers': {
+              'playwright': {
+                'url': `${urlPrefixHumanReadable}/sse`
+              }
+            }
+          }, undefined, 2));
+        });
+      } else {
+        const transport = new StdioServerTransport();
+        await server.connect(transport);
+      }
     });
 
 function setupExitWatchdog(server: Server) {