MCP Server Tauri

import { z } from 'zod'; import { getDefaultHost, getDefaultPort } from '../config.js'; import { AppDiscovery } from './app-discovery.js'; import { PluginClient } from './plugin-client.js'; import { resetInitialization } from './webview-executor.js'; import { createMcpLogger } from '../logger.js'; const sessionLogger = createMcpLogger('SESSION'); /** * Session Manager - Native IPC-based session management * * This module provides lightweight native session management using Tauri IPC. * The "session" concept is maintained for API compatibility. * * Connection Strategy: * 1. Try localhost first (most reliable for simulators/emulators/desktop) * 2. If localhost fails and a remote host is configured, try that host * 3. Return error if all connection attempts fail */ // ============================================================================ // Schemas // ============================================================================ export const ManageDriverSessionSchema = z.object({ action: z.enum([ 'start', 'stop', 'status' ]).describe('Action to perform: start or stop the session, or check status'), host: z.string().optional().describe( 'Host address to connect to (e.g., 192.168.1.100). Falls back to MCP_BRIDGE_HOST or TAURI_DEV_HOST env vars' ), port: z.number().optional().describe('Port to connect to (default: 9223)'), appIdentifier: z.union([ z.string(), z.number() ]).optional().describe( 'App identifier (port number or bundle ID) to stop. Only used with action "stop". If omitted, stops all sessions.' ), }); // ============================================================================ // Types // ============================================================================ export interface SessionInfo { name: string; identifier: string | null; host: string; port: number; client: PluginClient; connected: boolean; } // ============================================================================ // Module State // ============================================================================ // AppDiscovery instance - recreated when host changes let appDiscovery: AppDiscovery | null = null; // Track multiple concurrent sessions keyed by port const activeSessions = new Map<number, SessionInfo>(); // Track the default app (most recently connected) let defaultPort: number | null = null; /** * Check if any session is currently active. * @returns true if at least one session exists */ export function hasActiveSession(): boolean { return activeSessions.size > 0; } /** * Get a specific session by port. */ export function getSession(port: number): SessionInfo | null { return activeSessions.get(port) ?? null; } /** * Get the default session (most recently connected). */ export function getDefaultSession(): SessionInfo | null { if (defaultPort !== null && activeSessions.has(defaultPort)) { const session = activeSessions.get(defaultPort); return session ?? null; } return null; } /** * Get all active sessions. */ export function getAllSessions(): SessionInfo[] { return Array.from(activeSessions.values()); } function getAppDiscovery(host: string): AppDiscovery { if (!appDiscovery || appDiscovery.host !== host) { appDiscovery = new AppDiscovery(host); } return appDiscovery; } /** * Resolve target app from port or identifier. * Returns the appropriate session based on the routing logic. */ export function resolveTargetApp(portOrIdentifier?: string | number): SessionInfo { if (activeSessions.size === 0) { throw new Error( 'No active session. Call tauri_driver_session with action "start" first to connect to a Tauri app.' ); } // Single app - return it if (activeSessions.size === 1) { const session = activeSessions.values().next().value; if (!session) { throw new Error('Session state inconsistent'); } return session; } // Multiple apps - need identifier or use default if (portOrIdentifier !== undefined) { // Try port lookup first const port = typeof portOrIdentifier === 'number' ? portOrIdentifier : parseInt(String(portOrIdentifier), 10); if (!isNaN(port) && activeSessions.has(port)) { const session = activeSessions.get(port); if (session) { return session; } } // Try identifier match for (const session of activeSessions.values()) { if (session.identifier === String(portOrIdentifier)) { return session; } } throw new Error(formatAppNotFoundError(portOrIdentifier)); } // Use default app if (defaultPort !== null && activeSessions.has(defaultPort)) { const session = activeSessions.get(defaultPort); if (session) { return session; } } throw new Error('No default app set. This should not happen.'); } /** * Format error message when app not found. */ function formatAppNotFoundError(identifier: string | number): string { const appList = Array.from(activeSessions.values()) .map((session) => { const isDefault = session.port === defaultPort; const defaultMarker = isDefault ? ' [DEFAULT]' : ''; return ` - ${session.port}: ${session.identifier || 'unknown'} (${session.host}:${session.port})${defaultMarker}`; }) .join('\n'); return ( `App "${identifier}" not found.\n\n` + `Connected apps:\n${appList}\n\n` + 'Use tauri_driver_session with action "status" to list all connected apps.' ); } /** * Promote the next default app when the current default is removed. * Selects the oldest remaining session (first in insertion order). */ function promoteNextDefault(): void { if (activeSessions.size > 0) { // Get first session (oldest) const firstSession = activeSessions.values().next().value; if (firstSession) { defaultPort = firstSession.port; sessionLogger.info(`Promoted port ${defaultPort} as new default app`); } else { defaultPort = null; } } else { defaultPort = null; } } async function handleStatusAction(): Promise<string> { if (activeSessions.size === 0) { return JSON.stringify({ connected: false, app: null, identifier: null, host: null, port: null, }); } if (activeSessions.size === 1) { const session = activeSessions.values().next().value; if (!session) { return JSON.stringify({ connected: false, app: null, identifier: null, host: null, port: null, }); } return JSON.stringify({ connected: true, app: session.name, identifier: session.identifier, host: session.host, port: session.port, }); } const apps = Array.from(activeSessions.values()).map((session) => { return { name: session.name, identifier: session.identifier, host: session.host, port: session.port, isDefault: session.port === defaultPort, }; }); return JSON.stringify({ connected: true, apps, totalCount: apps.length, defaultPort, }); } async function handleStartAction(host?: string, port?: number): Promise<string> { const configuredHost = host ?? getDefaultHost(); const configuredPort = port ?? getDefaultPort(); if (activeSessions.has(configuredPort)) { return `Already connected to app on port ${configuredPort}`; } let connectedSession: { name: string; host: string; port: number } | null = null; if (configuredHost !== 'localhost' && configuredHost !== '127.0.0.1') { try { connectedSession = await tryConnect('localhost', configuredPort); } catch{ // ignore } } if (!connectedSession) { try { connectedSession = await tryConnect(configuredHost, configuredPort); } catch{ // ignore } } if (!connectedSession) { const localhostDiscovery = getAppDiscovery('localhost'); const firstApp = await localhostDiscovery.getFirstAvailableApp(); if (firstApp) { try { connectedSession = await tryConnect('localhost', firstApp.port); } catch{ // ignore } } } if (!connectedSession) { return `Session start failed - no Tauri app found at localhost or ${configuredHost}:${configuredPort}`; } const client = new PluginClient(connectedSession.host, connectedSession.port); await client.connect(); const identifier = await fetchAppIdentifier(client); const sessionInfo: SessionInfo = { name: connectedSession.name, identifier, host: connectedSession.host, port: connectedSession.port, client, connected: true, }; activeSessions.set(connectedSession.port, sessionInfo); defaultPort = connectedSession.port; sessionLogger.info( `Session started: ${sessionInfo.name} (${sessionInfo.host}:${sessionInfo.port}) [DEFAULT]` ); return `Session started with app: ${sessionInfo.name} (${sessionInfo.host}:${sessionInfo.port}) [DEFAULT]`; } async function handleStopAction(appIdentifier?: string | number): Promise<string> { if (appIdentifier !== undefined) { const session = resolveTargetApp(appIdentifier); session.client.disconnect(); activeSessions.delete(session.port); if (session.port === defaultPort) { promoteNextDefault(); } sessionLogger.info(`Session stopped: ${session.name} (${session.host}:${session.port})`); return `Session stopped: ${session.name} (${session.host}:${session.port})`; } for (const session of activeSessions.values()) { session.client.disconnect(); } activeSessions.clear(); defaultPort = null; if (appDiscovery) { await appDiscovery.disconnectAll(); } resetInitialization(); sessionLogger.info('All sessions stopped'); return 'All sessions stopped'; } // ============================================================================ // Session Management // ============================================================================ /** * Try to connect to a specific host and port. * Returns session info on success, throws on failure. */ async function tryConnect(host: string, port: number): Promise<{ name: string; host: string; port: number }> { const discovery = getAppDiscovery(host); const session = await discovery.connectToPort(port, undefined, host); return { name: session.name, host: session.host, port: session.port, }; } /** * Fetch the app identifier from the backend state. * Must be called after a PluginClient is connected. * * @param client - The PluginClient to query * @returns The app identifier (bundle ID) or null if not available. Returns null when: * - The plugin doesn't support the identifier field (older versions) * - The backend state request fails * - The identifier field is missing from the response */ async function fetchAppIdentifier(client: PluginClient): Promise<string | null> { try { const response = await client.sendCommand({ command: 'invoke_tauri', args: { command: 'plugin:mcp-bridge|get_backend_state', args: {} }, }); if (!response.success || !response.data) { return null; } const state = response.data as { app?: { identifier?: string } }; // Return null if identifier is not present (backward compat with older plugins) return state.app?.identifier ?? null; } catch{ // Return null on any error (e.g., older plugin version that doesn't support this) return null; } } /** * Manage session lifecycle (start, stop, or status). * * Connection strategy for 'start': * 1. Try localhost:{port} first (most reliable for simulators/emulators/desktop) * 2. If localhost fails AND a different host is configured, try {host}:{port} * 3. If both fail, try auto-discovery on localhost * 4. Return error if all attempts fail * * @param action - 'start', 'stop', or 'status' * @param host - Optional host address (defaults to env var or localhost) * @param port - Optional port number (defaults to 9223) * @param appIdentifier - Optional app identifier for 'stop' action (port or bundle ID) * @returns For 'start'/'stop': A message string describing the result. * For 'status': A JSON string with connection details */ export async function manageDriverSession( action: 'start' | 'stop' | 'status', host?: string, port?: number, appIdentifier?: string | number ): Promise<string> { switch (action) { case 'status': { return handleStatusAction(); } case 'start': { return handleStartAction(host, port); } case 'stop': { return handleStopAction(appIdentifier); } default: { return handleStopAction(appIdentifier); } } }