echo-client.js•4.04 kB
#!/usr/bin/env node
/**
* Example client for the Echo Server using the MCP SDK directly
* This demonstrates proper SDK mechanisms for client-server communication
*/
import { Client } from '@modelcontextprotocol/sdk/client/index.js';
import { StdioClientTransport } from '@modelcontextprotocol/sdk/client/stdio.js';
import path from 'path';
import { fileURLToPath } from 'url';
// ANSI color codes
const colors = {
reset: '\x1b[0m',
green: '\x1b[32m',
yellow: '\x1b[33m',
blue: '\x1b[34m',
red: '\x1b[31m',
};
// Path to the echo server
const SERVER_PATH = path.join(
path.dirname(fileURLToPath(import.meta.url)),
'../servers/scripts/echo-server'
);
/**
* Main client function
*/
async function runClient() {
console.log(`${colors.blue}===== Echo Server SDK Client Example =====\n${colors.reset}`);
// Create a transport to the echo server
console.log(`${colors.yellow}Starting echo server...${colors.reset}`);
const transport = new StdioClientTransport({
command: 'node',
args: [SERVER_PATH],
});
// Create a client
const client = new Client(
{
name: 'test-client',
version: '1.0.0',
},
{
capabilities: {
tools: {},
},
}
);
try {
// Connect to the server
await client.connect(transport);
console.log(`${colors.green}Connected to echo server${colors.reset}\n`);
// Test: List available tools
await runTest('List Available Tools', async () => {
const tools = await client.listTools();
return tools;
});
// Test: Echo basic message
await runTest('Echo Basic Message', async () => {
const result = await client.callTool({
name: 'echo',
arguments: {
message: 'Hello, Echo Server!',
},
});
return result;
});
// Test: Echo special characters
await runTest('Echo Special Characters', async () => {
const result = await client.callTool({
name: 'echo',
arguments: {
message: '!@#$%^&*()_+{}[]|\\:;"\'<>,.?/',
},
});
return result;
});
// Test: Echo empty message
await runTest('Echo Empty Message', async () => {
const result = await client.callTool({
name: 'echo',
arguments: {
message: '',
},
});
return result;
});
// Test: Echo long message
await runTest('Echo Long Message', async () => {
const longMessage = 'This is a very long message that repeats. '.repeat(100);
const result = await client.callTool({
name: 'echo',
arguments: {
message: longMessage,
},
});
return {
content: [
{
type: result.content[0].type,
text: `${result.content[0].text.substring(0, 50)}... (${
result.content[0].text.length
} characters)`,
},
],
};
});
} catch (error) {
console.error(`${colors.red}Error: ${error.message}${colors.reset}`);
} finally {
// Disconnect from the server
try {
if (client.disconnect) {
await client.disconnect();
console.log(`${colors.yellow}Disconnected from echo server${colors.reset}`);
}
} catch (error) {
console.error(`${colors.red}Error disconnecting: ${error.message}${colors.reset}`);
}
}
console.log(`\n${colors.blue}===== Client Example Completed =====\n${colors.reset}`);
}
/**
* Helper function to run a test and display results
*/
async function runTest(testName, testFn) {
console.log(`${colors.yellow}Test: ${testName}${colors.reset}`);
try {
const result = await testFn();
console.log(`${colors.green}Result:${colors.reset}`);
console.log(JSON.stringify(result, null, 2));
} catch (error) {
console.error(`${colors.red}Error: ${error.message}${colors.reset}`);
}
console.log('');
}
// Run the client
runClient().catch(error => {
console.error(`${colors.red}Fatal error: ${error.message}${colors.reset}`);
process.exit(1);
});