stdio.js•3.25 kB
"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.StdioServerTransport = void 0;
const node_process_1 = __importDefault(require("node:process"));
const stdio_js_1 = require("../shared/stdio.js");
/**
* Server transport for stdio: this communicates with a MCP client by reading from the current process' stdin and writing to stdout.
*
* This transport is only available in Node.js environments.
*/
class StdioServerTransport {
constructor(_stdin = node_process_1.default.stdin, _stdout = node_process_1.default.stdout) {
this._stdin = _stdin;
this._stdout = _stdout;
this._readBuffer = new stdio_js_1.ReadBuffer();
this._started = false;
// Arrow functions to bind `this` properly, while maintaining function identity.
this._ondata = (chunk) => {
this._readBuffer.append(chunk);
this.processReadBuffer();
};
this._onerror = (error) => {
var _a;
(_a = this.onerror) === null || _a === void 0 ? void 0 : _a.call(this, error);
};
}
/**
* Starts listening for messages on stdin.
*/
async start() {
if (this._started) {
throw new Error('StdioServerTransport already started! If using Server class, note that connect() calls start() automatically.');
}
this._started = true;
this._stdin.on('data', this._ondata);
this._stdin.on('error', this._onerror);
}
processReadBuffer() {
var _a, _b;
while (true) {
try {
const message = this._readBuffer.readMessage();
if (message === null) {
break;
}
(_a = this.onmessage) === null || _a === void 0 ? void 0 : _a.call(this, message);
}
catch (error) {
(_b = this.onerror) === null || _b === void 0 ? void 0 : _b.call(this, error);
}
}
}
async close() {
var _a;
// Remove our event listeners first
this._stdin.off('data', this._ondata);
this._stdin.off('error', this._onerror);
// Check if we were the only data listener
const remainingDataListeners = this._stdin.listenerCount('data');
if (remainingDataListeners === 0) {
// Only pause stdin if we were the only listener
// This prevents interfering with other parts of the application that might be using stdin
this._stdin.pause();
}
// Clear the buffer and notify closure
this._readBuffer.clear();
(_a = this.onclose) === null || _a === void 0 ? void 0 : _a.call(this);
}
send(message) {
return new Promise(resolve => {
const json = (0, stdio_js_1.serializeMessage)(message);
if (this._stdout.write(json)) {
resolve();
}
else {
this._stdout.once('drain', resolve);
}
});
}
}
exports.StdioServerTransport = StdioServerTransport;
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