SSH MCP Server

/** * SSH Server Echo Management Test * * This test validates that SSH PTY is configured to disable server echo, * preventing character duplication when browsers send character-by-character input. * * CRITICAL ISSUE: SSH servers naturally echo characters back to the client, * causing double display when browsers send individual keystrokes via WebSocket. * * Required Fix: Configure SSH PTY with ECHO disabled and manage echo modes per session. */ import { describe, test, expect, beforeAll, afterAll, beforeEach, afterEach } from '@jest/globals'; import { SSHConnectionManager } from '../src/ssh-connection-manager.js'; import WebSocket from 'ws'; import { spawn, ChildProcess } from 'child_process'; describe('SSH Server Echo Management', () => { let sshManager: SSHConnectionManager; let mcpProcess: ChildProcess; let testSessionName: string; let webSocketPort: number; beforeAll(async () => { // Start MCP server process for testing mcpProcess = spawn('npm', ['start'], { cwd: '/home/jsbattig/Dev/ls-ssh-mcp', stdio: ['pipe', 'pipe', 'pipe'], env: { ...process.env, NODE_ENV: 'test' } }); // Wait for MCP server to be ready await new Promise<void>((resolve, reject) => { const timeout = setTimeout(() => { reject(new Error('MCP server failed to start within timeout')); }, 10000); mcpProcess.stdout?.on('data', (data) => { const output = data.toString(); if (output.includes('MCP Server listening on')) { clearTimeout(timeout); resolve(); } }); mcpProcess.stderr?.on('data', (data) => { console.error('MCP server error:', data.toString()); }); mcpProcess.on('error', (error) => { clearTimeout(timeout); reject(error); }); }); // Initialize SSH connection manager sshManager = new SSHConnectionManager(8080); webSocketPort = 8080; }, 30000); afterAll(async () => { // Clean up test session if (sshManager && testSessionName && sshManager.hasSession(testSessionName)) { await sshManager.disconnectSession(testSessionName); } // Terminate MCP process if (mcpProcess) { mcpProcess.kill('SIGTERM'); // Wait for graceful shutdown await new Promise<void>((resolve) => { mcpProcess.on('exit', () => resolve()); setTimeout(() => { mcpProcess.kill('SIGKILL'); resolve(); }, 5000); }); } }, 15000); beforeEach(() => { testSessionName = `final-validation-${Date.now()}`; }); afterEach(async () => { if (sshManager && testSessionName && sshManager.hasSession(testSessionName)) { await sshManager.disconnectSession(testSessionName); } }); test('should configure SSH PTY with ECHO disabled to prevent server-side character duplication', async () => { // FAILING TEST: This will fail because SSH PTY currently uses default echo settings // Create SSH connection with echo management test session const connection = await sshManager.createConnection({ name: testSessionName, host: 'localhost', username: 'jsbattig', keyFilePath: '~/.ssh/id_ed25519' }); expect(connection.status).toBe('connected'); // Connect to WebSocket monitoring endpoint const wsUrl = `ws://localhost:${webSocketPort}/session/${testSessionName}`; const ws = new WebSocket(wsUrl); const webSocketMessages: string[] = []; ws.on('open', () => { console.log('WebSocket connected for echo management test'); }); ws.on('message', (data) => { const message = data.toString(); webSocketMessages.push(message); console.log('WebSocket received:', JSON.stringify(message)); }); // Wait for initial connection and prompt await new Promise<void>((resolve) => { const checkInterval = setInterval(() => { if (webSocketMessages.some(msg => msg.includes('$') || msg.includes('#') || msg.includes('>'))) { clearInterval(checkInterval); resolve(); } }, 100); setTimeout(() => { clearInterval(checkInterval); resolve(); }, 5000); }); console.log('Initial WebSocket messages:', webSocketMessages); // Clear previous messages to focus on character input test webSocketMessages.length = 0; // TEST CASE: Send character-by-character input via terminal_input_raw const testCharacters = ['h', 'e', 'l', 'l', 'o']; for (const char of testCharacters) { // Send individual character like real browser would sshManager.sendTerminalInput(testSessionName, char); // Small delay to allow processing await new Promise(resolve => setTimeout(resolve, 50)); } // Send Enter to complete the command sshManager.sendTerminalInput(testSessionName, '\n'); // Wait for command completion and response await new Promise<void>((resolve) => { const checkInterval = setInterval(() => { const lastMessage = webSocketMessages[webSocketMessages.length - 1] || ''; if (lastMessage.includes('$') || lastMessage.includes('#') || lastMessage.includes('>')) { clearInterval(checkInterval); resolve(); } }, 100); setTimeout(() => { clearInterval(checkInterval); resolve(); }, 3000); }); ws.close(); console.log('Character input WebSocket messages:', webSocketMessages); // CRITICAL ASSERTION: Verify no character duplication from server echo const concatenatedOutput = webSocketMessages.join(''); // This test should FAIL initially because SSH server echo is enabled // Expected behavior: Each character should appear only once in terminal output // Actual behavior: Each character appears twice due to server echo // Count occurrences of each test character in the output const characterCounts = testCharacters.reduce((counts, char) => { const occurrences = (concatenatedOutput.match(new RegExp(char, 'g')) || []).length; counts[char] = occurrences; return counts; }, {} as Record<string, number>); console.log('Character occurrence counts:', characterCounts); // EXPECTED FAILURE: This assertion should fail showing double characters // After fix: Each character should appear exactly once (no server echo) testCharacters.forEach(char => { expect(characterCounts[char]).toBe(1); // This will fail - shows server echo issue }); // Additional assertion: No double character sequences in output testCharacters.forEach(char => { const doubleChar = char + char; expect(concatenatedOutput).not.toContain(doubleChar); }); // Verify the complete word appears correctly without duplication expect(concatenatedOutput).toMatch(/hello/); // Should appear once, not "hheelllloo" }, 30000); test('should track raw input mode per session and manage echo appropriately', async () => { // FAILING TEST: This will fail because raw input mode tracking is not implemented const connection = await sshManager.createConnection({ name: testSessionName, host: 'localhost', username: 'jsbattig', keyFilePath: '~/.ssh/id_ed25519' }); expect(connection.status).toBe('connected'); // Test that session can switch between echo modes // Raw input mode: ECHO disabled // Normal input mode: ECHO enabled (for backward compatibility) // This test will fail because the session tracking is not implemented // The fix should add session state to track input modes // For now, this is a placeholder test that will fail // Implementation should add: // 1. Session state tracking for input modes // 2. PTY reconfiguration methods // 3. Mode switching based on input type (terminal_input_raw vs terminal_input) expect(true).toBe(false); // Intentional failure until implementation }, 10000); test('should demonstrate current SSH server echo problem', async () => { // DEMONSTRATION TEST: Shows the current problem with server echo const connection = await sshManager.createConnection({ name: testSessionName, host: 'localhost', username: 'jsbattig', keyFilePath: '~/.ssh/id_ed25519' }); expect(connection.status).toBe('connected'); const wsUrl = `ws://localhost:${webSocketPort}/session/${testSessionName}`; const ws = new WebSocket(wsUrl); const webSocketMessages: string[] = []; ws.on('message', (data) => { webSocketMessages.push(data.toString()); }); // Wait for initial prompt await new Promise<void>((resolve) => { const checkInterval = setInterval(() => { if (webSocketMessages.some(msg => msg.includes('$') || msg.includes('#') || msg.includes('>'))) { clearInterval(checkInterval); resolve(); } }, 100); setTimeout(() => { clearInterval(checkInterval); resolve(); }, 3000); }); // Clear messages for clean test webSocketMessages.length = 0; // Send single character 'x' sshManager.sendTerminalInput(testSessionName, 'x'); // Wait a moment for echo await new Promise(resolve => setTimeout(resolve, 200)); ws.close(); const output = webSocketMessages.join(''); console.log('Single character test output:', JSON.stringify(output)); // DEMONSTRATION: This will likely show the character appears twice // Once from browser input, once from SSH server echo const xCount = (output.match(/x/g) || []).length; console.log('Character "x" appears', xCount, 'times in output'); // Document the current behavior (this may pass showing the problem) expect(xCount).toBeGreaterThan(0); }, 15000); });