MCP Server Tauri

import { z } from 'zod'; import { connectPlugin } from './plugin-client.js'; import { hasActiveSession, getDefaultSession, resolveTargetApp } from './session-manager.js'; import { createMcpLogger } from '../logger.js'; import { buildScreenshotScript, buildScreenshotCaptureScript, getHtml2CanvasSource, HTML2CANVAS_SCRIPT_ID, } from './scripts/html2canvas-loader.js'; import { registerScript, isScriptRegistered } from './script-manager.js'; /** * WebView Executor - Native IPC-based JavaScript execution * * This module provides native Tauri IPC-based execution, * enabling cross-platform support (Linux, Windows, macOS) without external dependencies. * * Communication flow: * MCP Server (Node.js) → plugin-client (WebSocket) → mcp-bridge plugin → Tauri Webview */ // ============================================================================ // Auto-Initialization System // ============================================================================ let isInitialized = false; const driverLogger = createMcpLogger('DRIVER'); /** * Ensures the MCP server is fully initialized and ready to use. * This is called automatically by all tool functions. * * Initialization includes: * - Verifying an active session exists (via tauri_driver_session) * - Connecting to the plugin WebSocket using session config * - Console capture is already initialized by bridge.js in the Tauri app * * This function is idempotent - calling it multiple times is safe. * * @throws Error if no session is active (tauri_driver_session must be called first) */ export async function ensureReady(): Promise<void> { if (isInitialized) { return; } // Require an active session to prevent connecting to wrong app if (!hasActiveSession()) { throw new Error( 'No active session. Call tauri_driver_session with action "start" first to connect to a Tauri app.' ); } // Get default session for initial connection const session = getDefaultSession(); if (session) { await connectPlugin(session.host, session.port); } isInitialized = true; } /** * Reset initialization state (useful for testing or reconnecting). */ export function resetInitialization(): void { isInitialized = false; } // ============================================================================ // Core Execution Functions // ============================================================================ export interface ExecuteInWebviewResult { result: string; windowLabel: string; warning?: string; } /** * Execute JavaScript in the Tauri webview using native IPC via WebSocket. * * @param script - JavaScript code to execute in the webview context * @param windowId - Optional window label to target (defaults to "main") * @param appIdentifier - Optional app identifier to target specific app * @returns Result of the script execution with window context */ export async function executeInWebview(script: string, windowId?: string, appIdentifier?: string | number): Promise<string> { const { result } = await executeInWebviewWithContext(script, windowId, appIdentifier); return result; } /** * Execute JavaScript in the Tauri webview and return window context. * * @param script - JavaScript code to execute in the webview context * @param windowId - Optional window label to target (defaults to "main") * @param appIdentifier - Optional app identifier to target specific app * @returns Result of the script execution with window context */ export async function executeInWebviewWithContext( script: string, windowId?: string, appIdentifier?: string | number ): Promise<ExecuteInWebviewResult> { try { // Ensure we're fully initialized await ensureReady(); // Resolve target session const session = resolveTargetApp(appIdentifier); const client = session.client; // Send script directly - Rust handles wrapping and IPC callbacks. // Use 7s timeout (longer than Rust's 5s) so errors return before Node times out. const response = await client.sendCommand({ command: 'execute_js', args: { script, windowLabel: windowId }, }, 7000); if (!response.success) { throw new Error(response.error || 'Unknown execution error'); } // Extract window context from response const windowContext = response.windowContext; // Parse and return the result const data = response.data; let result: string; if (data === null || data === undefined) { result = 'null'; } else if (typeof data === 'string') { result = data; } else { result = JSON.stringify(data); } return { result, windowLabel: windowContext?.windowLabel || 'main', warning: windowContext?.warning, }; } catch(error: unknown) { const message = error instanceof Error ? error.message : String(error); throw new Error(`WebView execution failed: ${message}`); } } /** * Execute async JavaScript in the webview with timeout support. * * @param script - JavaScript code to execute (can use await) * @param windowId - Optional window label to target (defaults to "main") * @param timeout - Timeout in milliseconds (default: 5000) * @returns Result of the script execution */ export async function executeAsyncInWebview(script: string, windowId?: string, timeout = 5000): Promise<string> { const wrappedScript = ` return (async () => { const timeoutPromise = new Promise((_, reject) => { setTimeout(() => reject(new Error('Script execution timeout')), ${timeout}); }); const scriptPromise = (async () => { ${script} })(); return await Promise.race([scriptPromise, timeoutPromise]); })(); `; return executeInWebview(wrappedScript, windowId); } // ============================================================================ // Console Log Capture System // ============================================================================ /** * Initialize console log capture in the webview. * This intercepts console methods and stores logs in memory. * * NOTE: Console capture is now automatically initialized by bridge.js when the * Tauri app starts. This function is kept for backwards compatibility and will * simply return early if capture is already initialized. */ export async function initializeConsoleCapture(): Promise<string> { const script = ` if (!window.__MCP_CONSOLE_LOGS__) { window.__MCP_CONSOLE_LOGS__ = []; const originalConsole = { ...console }; ['log', 'debug', 'info', 'warn', 'error'].forEach(level => { console[level] = function(...args) { window.__MCP_CONSOLE_LOGS__.push({ level: level, message: args.map(a => { try { return typeof a === 'object' ? JSON.stringify(a) : String(a); } catch(e) { return String(a); } }).join(' '), timestamp: Date.now() }); // Keep original console behavior originalConsole[level].apply(console, args); }; }); return 'Console capture initialized'; } return 'Console capture already initialized'; `; return executeInWebview(script); } /** * Retrieve captured console logs with optional filtering. * * @param filter - Optional regex pattern to filter log messages * @param since - Optional ISO timestamp to filter logs after this time * @param windowId - Optional window label to target (defaults to "main") * @param appIdentifier - Optional app identifier to target specific app * @returns Formatted console logs as string */ export async function getConsoleLogs( filter?: string, since?: string, windowId?: string, appIdentifier?: string | number ): Promise<string> { const filterStr = filter ? filter.replace(/'/g, '\\\'') : ''; const sinceStr = since || ''; const script = ` const logs = window.__MCP_CONSOLE_LOGS__ || []; let filtered = logs; if ('${sinceStr}') { const sinceTime = new Date('${sinceStr}').getTime(); filtered = filtered.filter(l => l.timestamp > sinceTime); } if ('${filterStr}') { try { const regex = new RegExp('${filterStr}', 'i'); filtered = filtered.filter(l => regex.test(l.message)); } catch(e) { throw new Error('Invalid filter regex: ' + e.message); } } return filtered.map(l => '[ ' + new Date(l.timestamp).toISOString() + ' ] [ ' + l.level.toUpperCase() + ' ] ' + l.message ).join('\\n'); `; return executeInWebview(script, windowId, appIdentifier); } /** * Clear all captured console logs. */ export async function clearConsoleLogs(): Promise<string> { const script = ` window.__MCP_CONSOLE_LOGS__ = []; return 'Console logs cleared'; `; return executeInWebview(script); } // ============================================================================ // Screenshot Functionality // ============================================================================ import type { ToolContent } from '../tools-registry.js'; interface WindowContextInfo { windowLabel: string; totalWindows: number; warning?: string; } /** * Result of a screenshot capture, containing both image data and optional context. */ export interface ScreenshotResult { content: ToolContent[]; } /** * Parse a data URL to extract the base64 data and mime type. */ function parseDataUrl(dataUrl: string): { data: string; mimeType: string } | null { const match = dataUrl.match(/^data:(image\/(?:png|jpeg));base64,(.+)$/); if (!match) { return null; } return { mimeType: match[1], data: match[2] }; } /** * Build screenshot result with image content and optional text context. */ function buildScreenshotResult(dataUrl: string, method: string, windowContext?: WindowContextInfo): ScreenshotResult { const parsed = parseDataUrl(dataUrl); if (!parsed) { throw new Error(`Invalid data URL format: ${dataUrl.substring(0, 50)}...`); } const content: ToolContent[] = []; // Add context text if there's window info or warnings let contextText = `Screenshot captured via ${method}`; if (windowContext) { contextText += ` in window "${windowContext.windowLabel}"`; if (windowContext.warning) { contextText += `\n\n⚠️ ${windowContext.warning}`; } } content.push({ type: 'text', text: contextText }); // Add the image content content.push({ type: 'image', data: parsed.data, mimeType: parsed.mimeType, }); return { content }; } export interface CaptureScreenshotOptions { format?: 'png' | 'jpeg'; quality?: number; windowId?: string; appIdentifier?: string | number; } /** * Prepares the html2canvas script for screenshot capture. * Tries to use the script manager for persistence, falls back to inline injection. */ async function prepareHtml2canvasScript(format: 'png' | 'jpeg', quality: number): Promise<string> { try { // Check if html2canvas is already registered const isRegistered = await isScriptRegistered(HTML2CANVAS_SCRIPT_ID); if (!isRegistered) { // Register html2canvas via script manager for persistence across navigations const html2canvasSource = getHtml2CanvasSource(); await registerScript(HTML2CANVAS_SCRIPT_ID, 'inline', html2canvasSource); } // Use the capture-only script since html2canvas is now registered return buildScreenshotCaptureScript(format, quality); } catch{ // Script manager not available, fall back to inline injection return buildScreenshotScript(format, quality); } } /** * Capture a screenshot of the entire webview. * * @param options - Screenshot options (format, quality, windowId, appIdentifier) * @returns Screenshot result with image content */ export async function captureScreenshot(options: CaptureScreenshotOptions = {}): Promise<ScreenshotResult> { const { format = 'png', quality = 90, windowId, appIdentifier } = options; // Primary implementation: Use native platform-specific APIs // - macOS: WKWebView takeSnapshot // - Windows: WebView2 CapturePreview // - Linux: Chromium/WebKit screenshot APIs try { // Ensure we're fully initialized await ensureReady(); // Resolve target session const session = resolveTargetApp(appIdentifier); const client = session.client; // Use longer timeout (15s) for native screenshot - the Rust code waits up to 10s const response = await client.sendCommand({ command: 'capture_native_screenshot', args: { format, quality, windowLabel: windowId, }, }, 15000); if (!response.success || !response.data) { throw new Error(response.error || 'Native screenshot returned invalid data'); } // The native command returns a base64 data URL const dataUrl = response.data as string; if (!dataUrl || !dataUrl.startsWith('data:image/')) { throw new Error('Native screenshot returned invalid data'); } // Build response with window context return buildScreenshotResult(dataUrl, 'native API', response.windowContext); } catch(nativeError: unknown) { // Log the native error for debugging, then fall back const nativeMsg = nativeError instanceof Error ? nativeError.message : String(nativeError); driverLogger.error(`Native screenshot failed: ${nativeMsg}, falling back to html2canvas`); } // Fallback 1: Use html2canvas library for high-quality DOM rendering // Try to use the script manager to register html2canvas for persistence const html2canvasScript = await prepareHtml2canvasScript(format, quality); // Fallback: Try Screen Capture API if available // Note: This script is wrapped by executeAsyncInWebview, so we don't need an IIFE const screenCaptureScript = ` // Check if Screen Capture API is available if (!navigator.mediaDevices || !navigator.mediaDevices.getDisplayMedia) { throw new Error('Screen Capture API not available'); } // Request screen capture permission and get the stream const stream = await navigator.mediaDevices.getDisplayMedia({ video: { displaySurface: 'window', cursor: 'never' }, audio: false }); // Get the video track const videoTrack = stream.getVideoTracks()[0]; if (!videoTrack) { throw new Error('No video track available'); } // Create a video element to display the stream const video = document.createElement('video'); video.srcObject = stream; video.autoplay = true; // Wait for the video to load metadata await new Promise((resolve, reject) => { video.onloadedmetadata = resolve; video.onerror = reject; setTimeout(() => reject(new Error('Video load timeout')), 5000); }); // Play the video await video.play(); // Create canvas to capture the frame const canvas = document.createElement('canvas'); const ctx = canvas.getContext('2d'); // Set canvas dimensions to match video canvas.width = video.videoWidth; canvas.height = video.videoHeight; // Draw the video frame to canvas ctx.drawImage(video, 0, 0, canvas.width, canvas.height); // Stop all tracks to release the capture stream.getTracks().forEach(track => track.stop()); // Convert to data URL with specified format and quality const mimeType = '${format}' === 'jpeg' ? 'image/jpeg' : 'image/png'; return canvas.toDataURL(mimeType, ${quality / 100}); `; try { // Try html2canvas second (after native APIs) const result = await executeAsyncInWebview(html2canvasScript, undefined, 10000); // Longer timeout for library loading // Validate that we got a real data URL, not 'null' or empty if (result && result !== 'null' && result.startsWith('data:image/')) { return buildScreenshotResult(result, 'html2canvas'); } throw new Error(`html2canvas returned invalid result: ${result?.substring(0, 100) || 'null'}`); } catch(html2canvasError: unknown) { try { // Fallback to Screen Capture API const result = await executeAsyncInWebview(screenCaptureScript); // Validate that we got a real data URL if (result && result.startsWith('data:image/')) { return buildScreenshotResult(result, 'Screen Capture API'); } throw new Error(`Screen Capture API returned invalid result: ${result?.substring(0, 50) || 'null'}`); } catch(screenCaptureError: unknown) { // All methods failed - throw a proper error const html2canvasMsg = html2canvasError instanceof Error ? html2canvasError.message : 'html2canvas failed'; const screenCaptureMsg = screenCaptureError instanceof Error ? screenCaptureError.message : 'Screen Capture API failed'; throw new Error( 'Screenshot capture failed. Native API not available, ' + `html2canvas error: ${html2canvasMsg}, ` + `Screen Capture API error: ${screenCaptureMsg}` ); } } } // ============================================================================ // Schemas for Validation // ============================================================================ export const ExecuteScriptSchema = z.object({ script: z.string().describe('JavaScript code to execute in the webview'), }); export const GetConsoleLogsSchema = z.object({ filter: z.string().optional().describe('Regex or keyword to filter logs'), since: z.string().optional().describe('ISO timestamp to filter logs since'), }); export const CaptureScreenshotSchema = z.object({ format: z.enum([ 'png', 'jpeg' ]).optional().default('png').describe('Image format'), quality: z.number().min(0).max(100).optional().describe('JPEG quality (0-100)'), });