Add support for websockets - treat language server as WS server

Author: Krzysztof-Cieslak

package.json

@@ -49,6 +49,7 @@
     "@types/node": "^18.19.15",
     "@types/semver": "^7.5.6",
     "@types/which": "^3.0.3",
+    "@types/ws": "^8.18.1",
     "@typescript-eslint/eslint-plugin": "^6.21.0",
     "@typescript-eslint/parser": "^6.21.0",
     "commander": "^12.0.0",
@@ -74,7 +75,9 @@
     "vscode-languageserver-protocol": "^3.17.5",
     "vscode-languageserver-textdocument": "1.0.11",
     "vscode-uri": "^3.0.8",
+    "vscode-ws-jsonrpc": "^3.4.0",
     "which": "^4.0.0",
-    "why-is-node-running": "^2.2.2"
+    "why-is-node-running": "^2.2.2",
+    "ws": "^8.18.1"
   }
 }

src/cli.ts

@@ -5,17 +5,19 @@
  * You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
  */
 
-import { readFileSync } from 'node:fs';
+// import { readFileSync } from 'node:fs';
 import { Command } from 'commander';
-import lsp from 'vscode-languageserver';
+import lsp from 'vscode-languageserver/node.js';
+import { WebSocketMessageReader, WebSocketMessageWriter, toSocket } from 'vscode-ws-jsonrpc';
 import { createLspConnection } from './lsp-connection.js';
+import * as ws from 'ws';
 
 const DEFAULT_LOG_LEVEL = lsp.MessageType.Info;
-const { version } = JSON.parse(readFileSync(new URL('../package.json', import.meta.url), { encoding: 'utf8' }));
+// const { version } = JSON.parse(readFileSync(new URL('../package.json', import.meta.url), { encoding: 'utf8' }));
 
 const program = new Command('typescript-language-server')
-    .version(version)
-    .requiredOption('--stdio', 'use stdio')
+    // .version(version)
+    // .requiredOption('--stdio', 'use stdio')
     .option('--log-level <logLevel>', 'A number indicating the log level (4 = log, 3 = info, 2 = warn, 1 = error). Defaults to `2`.')
     .parse(process.argv);
 
@@ -30,6 +32,21 @@ if (options.logLevel) {
     }
 }
 
-createLspConnection({
-    showMessageLevel: logLevel as lsp.MessageType,
-}).listen();
+const port = 9090;
+const wss = new ws.WebSocketServer({ port });
+
+let connection: lsp.Connection | undefined = undefined;
+
+wss.on('connection', (socket) => {
+    if (connection) {
+        connection.dispose();
+    }
+    const sock = toSocket(socket);
+    const reader = new WebSocketMessageReader(sock);
+    const writer = new WebSocketMessageWriter(sock);
+    connection = lsp.createConnection(lsp.ProposedFeatures.all, reader, writer);
+
+    createLspConnection({
+        showMessageLevel: logLevel as lsp.MessageType,
+    }, connection).listen();
+});

src/lsp-connection.ts

@@ -14,8 +14,7 @@ export interface LspConnectionOptions {
     showMessageLevel: lsp.MessageType;
 }
 
-export function createLspConnection(options: LspConnectionOptions): lsp.Connection {
-    const connection = lsp.createConnection(lsp.ProposedFeatures.all);
+export function createLspConnection(options: LspConnectionOptions, connection: lsp.Connection): lsp.Connection {
     const lspClient = new LspClientImpl(connection);
     const logger = new LspClientLogger(lspClient, options.showMessageLevel);
     const server: LspServer = new LspServer({