Fetch API MCP Server

Implementation Reference

• src/handler.js:5-80 (handler)

  The core handler function fetchApiHandler that executes the HTTP request logic: constructs fetch options handling method, headers, cookies, formData or jsonData; performs fetch; parses response data based on content-type (JSON, text, or base64 binary); returns structured object with status, statusText, headers, and data; includes error handling.
  export async function fetchApiHandler({ url, method, headers = {}, formData, jsonData, cookies }) { try { // 准备请求选项 const options = { method, headers: { ...headers }, }; // 处理cookies if (cookies && Object.keys(cookies).length > 0) { const cookieString = Object.entries(cookies) .map(([key, value]) => `${key}=${value}`) .join('; '); options.headers.Cookie = cookieString; } // 处理请求体 if (method !== 'GET' && method !== 'HEAD') { if (formData && Object.keys(formData).length > 0) { // 处理表单数据 const form = new URLSearchParams(); Object.entries(formData).forEach(([key, value]) => { form.append(key, value); }); options.body = form.toString(); options.headers['Content-Type'] = 'application/x-www-form-urlencoded'; } else if (jsonData) { // 处理JSON数据 options.body = JSON.stringify(jsonData); options.headers['Content-Type'] = 'application/json'; } } // 发送请求 const response = await fetch(url, options); // 获取响应头 const responseHeaders = {}; response.headers.forEach((value, key) => { responseHeaders[key] = value; }); // 尝试解析响应体 let data; const contentType = response.headers.get('content-type'); if (contentType?.includes('application/json')) { data = await response.json(); } else if (contentType?.includes('text/')) { data = await response.text(); } else { // 对于二进制数据，转换为base64字符串 const buffer = await response.arrayBuffer(); data = Buffer.from(buffer).toString('base64'); } // 返回结果 return { status: response.status, statusText: response.statusText, headers: responseHeaders, data, }; } catch (error) { // 处理错误 return { status: 500, statusText: 'Internal Server Error', headers: {}, data: { error: error.message, stack: error.stack, }, }; } }
• src/index.js:15-22 (schema)

  Zod-based input schema defining parameters for the 'request' tool: required url (validated as URL string), optional method (enum with GET default), headers, formData, jsonData (any), and cookies (all records of strings).
  const inputSchema = { url: z.string().url(), method: z.enum(['GET', 'POST', 'PUT', 'DELETE', 'PATCH', 'HEAD', 'OPTIONS']).default('GET'), headers: z.record(z.string()).optional(), formData: z.record(z.string()).optional(), jsonData: z.any().optional(), cookies: z.record(z.string()).optional(), };
• src/index.js:25-37 (registration)

  MCP server tool registration for 'request': specifies name, input schema, thin async wrapper handler that calls fetchApiHandler and returns MCP-formatted text content (JSON stringified result), and detailed usage description in Chinese.
  server.tool( 'request', inputSchema, async (params) => { const result = await fetchApiHandler(params); return { content: [{ type: "text", text: JSON.stringify(result, null, 2) }] }; }, { description: '发送API请求并返回结果。使用方法：传入url（必需）、method（可选，默认GET）、headers（可选）、formData（可选，用于表单数据）、jsonData（可选，用于JSON数据）和cookies（可选）参数。例如：{ "url": "https://example.com/api", "method": "POST", "headers": {"Content-Type": "application/json"}, "jsonData": {"key": "value"}, "cookies": {"key": "value"} }。GET请求示例：{ "url": "https://example.com/api" }。返回包含status、statusText、headers和data的响应对象。' } );