@modelcontextprotocol/sdk
Version:
Model Context Protocol implementation for TypeScript
56 lines • 2.54 kB
JavaScript
;
var __importDefault = (this && this.__importDefault) || function (mod) {
return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.createMcpExpressApp = createMcpExpressApp;
const express_1 = __importDefault(require("express"));
const hostHeaderValidation_js_1 = require("./middleware/hostHeaderValidation.js");
/**
* Creates an Express application pre-configured for MCP servers.
*
* When the host is '127.0.0.1', 'localhost', or '::1' (the default is '127.0.0.1'),
* DNS rebinding protection middleware is automatically applied to protect against
* DNS rebinding attacks on localhost servers.
*
* @param options - Configuration options
* @returns A configured Express application
*
* @example
* ```typescript
* // Basic usage - defaults to 127.0.0.1 with DNS rebinding protection
* const app = createMcpExpressApp();
*
* // Custom host - DNS rebinding protection only applied for localhost hosts
* const app = createMcpExpressApp({ host: '0.0.0.0' }); // No automatic DNS rebinding protection
* const app = createMcpExpressApp({ host: 'localhost' }); // DNS rebinding protection enabled
*
* // Custom allowed hosts for non-localhost binding
* const app = createMcpExpressApp({ host: '0.0.0.0', allowedHosts: ['myapp.local', 'localhost'] });
* ```
*/
function createMcpExpressApp(options = {}) {
const { host = '127.0.0.1', allowedHosts } = options;
const app = (0, express_1.default)();
app.use(express_1.default.json());
// If allowedHosts is explicitly provided, use that for validation
if (allowedHosts) {
app.use((0, hostHeaderValidation_js_1.hostHeaderValidation)(allowedHosts));
}
else {
// Apply DNS rebinding protection automatically for localhost hosts
const localhostHosts = ['127.0.0.1', 'localhost', '::1'];
if (localhostHosts.includes(host)) {
app.use((0, hostHeaderValidation_js_1.localhostHostValidation)());
}
else if (host === '0.0.0.0' || host === '::') {
// Warn when binding to all interfaces without DNS rebinding protection
// eslint-disable-next-line no-console
console.warn(`Warning: Server is binding to ${host} without DNS rebinding protection. ` +
'Consider using the allowedHosts option to restrict allowed hosts, ' +
'or use authentication to protect your server.');
}
}
return app;
}
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