vscode-extension-samples/lsp-log-streaming-sample/client/src/extension.ts

/* --------------------------------------------------------------------------------------------
 * Copyright (c) Microsoft Corporation. All rights reserved.
 * Licensed under the MIT License. See License.txt in the project root for license information.
 * ------------------------------------------------------------------------------------------ */

import * as path from 'path';
import { workspace, commands, ExtensionContext, OutputChannel } from 'vscode';
import { WebSocket } from 'ws';

import {
	LanguageClient,
	LanguageClientOptions,
	ServerOptions,
	TransportKind
} from 'vscode-languageclient/node';

let client: LanguageClient;

export async function activate(context: ExtensionContext) {
	const socketPort = workspace.getConfiguration('languageServerExample').get('port', 7000);
	let socket: WebSocket | null = null;

	commands.registerCommand('languageServerExample.startStreaming', () => {
		// Establish websocket connection
		socket = new WebSocket(`ws://localhost:${socketPort}`);
	});

	// The server is implemented in node
	const serverModule = context.asAbsolutePath(
		path.join('server', 'out', 'server.js')
	);

	// If the extension is launched in debug mode then the debug server options are used
	// Otherwise the run options are used
	const serverOptions: ServerOptions = {
		run: { module: serverModule, transport: TransportKind.ipc },
		debug: {
			module: serverModule,
			transport: TransportKind.ipc,
		}
	};

	// The log to send
	let log = '';
	const websocketOutputChannel: OutputChannel = {
		name: 'websocket',
		// Only append the logs but send them later
		append(value: string) {
			log += value;
			console.log(value);
		},
		appendLine(value: string) {
			log += value;
			// Don't send logs until WebSocket initialization
			if (socket && socket.readyState === WebSocket.OPEN) {
				socket.send(log);
			}
			log = '';
		},
		clear() { /* empty */ },
		show() { /* empty */ },
		hide() { /* empty */ },
		dispose() { /* empty */ },
		replace() { /* empty */ }
	};

	// Options to control the language client
	const clientOptions: LanguageClientOptions = {
		// Register the server for plain text documents
		documentSelector: [{ scheme: 'file', language: 'plaintext' }],
		synchronize: {
			// Notify the server about file changes to '.clientrc files contained in the workspace
			fileEvents: workspace.createFileSystemWatcher('**/.clientrc')
		},
		// Hijacks all LSP logs and redirect them to a specific port through WebSocket connection
		outputChannel: websocketOutputChannel
	};

	// Create the language client and start the client.
	client = new LanguageClient(
		'languageServerExample',
		'Language Server Example',
		serverOptions,
		clientOptions
	);

	// Start the client. This will also launch the server
	await client.start();
}

export function deactivate(): Thenable<void> {
	if (!client) {
		return undefined;
	}
	return client.stop();
}