browserServerBackend.ts•5.13 kB
/**
* Copyright (c) Microsoft Corporation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import { fileURLToPath } from 'url';
import { z } from 'zod';
import { FullConfig } from './config.js';
import { Context } from './context.js';
import { logUnhandledError } from './log.js';
import { Response } from './response.js';
import { SessionLog } from './sessionLog.js';
import { filteredTools } from './tools.js';
import { packageJSON } from './package.js';
import { defineTool } from './tools/tool.js';
import type { Tool } from './tools/tool.js';
import type { BrowserContextFactory } from './browserContextFactory.js';
import type * as mcpServer from './mcp/server.js';
import type { ServerBackend } from './mcp/server.js';
type NonEmptyArray<T> = [T, ...T[]];
export type FactoryList = NonEmptyArray<BrowserContextFactory>;
export class BrowserServerBackend implements ServerBackend {
name = 'Playwright';
version = packageJSON.version;
private _tools: Tool[];
private _context: Context | undefined;
private _sessionLog: SessionLog | undefined;
private _config: FullConfig;
private _browserContextFactory: BrowserContextFactory;
constructor(config: FullConfig, factories: FactoryList) {
this._config = config;
this._browserContextFactory = factories[0];
this._tools = filteredTools(config);
if (factories.length > 1)
this._tools.push(this._defineContextSwitchTool(factories));
}
async initialize(server: mcpServer.Server): Promise<void> {
const capabilities = server.getClientCapabilities() as mcpServer.ClientCapabilities;
let rootPath: string | undefined;
if (capabilities.roots && (
server.getClientVersion()?.name === 'Visual Studio Code' ||
server.getClientVersion()?.name === 'Visual Studio Code - Insiders')) {
const { roots } = await server.listRoots();
const firstRootUri = roots[0]?.uri;
const url = firstRootUri ? new URL(firstRootUri) : undefined;
rootPath = url ? fileURLToPath(url) : undefined;
}
this._sessionLog = this._config.saveSession ? await SessionLog.create(this._config, rootPath) : undefined;
this._context = new Context({
tools: this._tools,
config: this._config,
browserContextFactory: this._browserContextFactory,
sessionLog: this._sessionLog,
clientInfo: { ...server.getClientVersion(), rootPath },
});
}
tools(): mcpServer.ToolSchema<any>[] {
return this._tools.map(tool => tool.schema);
}
async callTool(schema: mcpServer.ToolSchema<any>, parsedArguments: any) {
const context = this._context!;
const response = new Response(context, schema.name, parsedArguments);
const tool = this._tools.find(tool => tool.schema.name === schema.name)!;
context.setRunningTool(true);
try {
await tool.handle(context, parsedArguments, response);
await response.finish();
this._sessionLog?.logResponse(response);
} catch (error: any) {
response.addError(String(error));
} finally {
context.setRunningTool(false);
}
return response.serialize();
}
serverClosed() {
void this._context!.dispose().catch(logUnhandledError);
}
private _defineContextSwitchTool(factories: FactoryList): Tool<any> {
const self = this;
return defineTool({
capability: 'core',
schema: {
name: 'browser_connect',
title: 'Connect to a browser context',
description: [
'Connect to a browser using one of the available methods:',
...factories.map(factory => `- "${factory.name}": ${factory.description}`),
].join('\n'),
inputSchema: z.object({
method: z.enum(factories.map(factory => factory.name) as [string, ...string[]]).default(factories[0].name).describe('The method to use to connect to the browser'),
}),
type: 'readOnly',
},
async handle(context, params, response) {
const factory = factories.find(factory => factory.name === params.method);
if (!factory) {
response.addError('Unknown connection method: ' + params.method);
return;
}
await self._setContextFactory(factory);
response.addResult('Successfully changed connection method.');
}
});
}
private async _setContextFactory(newFactory: BrowserContextFactory) {
if (this._context) {
const options = {
...this._context.options,
browserContextFactory: newFactory,
};
await this._context.dispose();
this._context = new Context(options);
}
this._browserContextFactory = newFactory;
}
}