File size: 6,525 Bytes
a5d718a | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 | import spawn from 'cross-spawn';
import process from 'node:process';
import { PassThrough } from 'node:stream';
import { ReadBuffer, serializeMessage } from '../shared/stdio.js';
/**
* Environment variables to inherit by default, if an environment is not explicitly given.
*/
export const DEFAULT_INHERITED_ENV_VARS = process.platform === 'win32'
? [
'APPDATA',
'HOMEDRIVE',
'HOMEPATH',
'LOCALAPPDATA',
'PATH',
'PROCESSOR_ARCHITECTURE',
'SYSTEMDRIVE',
'SYSTEMROOT',
'TEMP',
'USERNAME',
'USERPROFILE',
'PROGRAMFILES'
]
: /* list inspired by the default env inheritance of sudo */
['HOME', 'LOGNAME', 'PATH', 'SHELL', 'TERM', 'USER'];
/**
* Returns a default environment object including only environment variables deemed safe to inherit.
*/
export function getDefaultEnvironment() {
const env = {};
for (const key of DEFAULT_INHERITED_ENV_VARS) {
const value = process.env[key];
if (value === undefined) {
continue;
}
if (value.startsWith('()')) {
// Skip functions, which are a security risk.
continue;
}
env[key] = value;
}
return env;
}
/**
* Client transport for stdio: this will connect to a server by spawning a process and communicating with it over stdin/stdout.
*
* This transport is only available in Node.js environments.
*/
export class StdioClientTransport {
constructor(server) {
this._readBuffer = new ReadBuffer();
this._stderrStream = null;
this._serverParams = server;
if (server.stderr === 'pipe' || server.stderr === 'overlapped') {
this._stderrStream = new PassThrough();
}
}
/**
* Starts the server process and prepares to communicate with it.
*/
async start() {
if (this._process) {
throw new Error('StdioClientTransport already started! If using Client class, note that connect() calls start() automatically.');
}
return new Promise((resolve, reject) => {
this._process = spawn(this._serverParams.command, this._serverParams.args ?? [], {
// merge default env with server env because mcp server needs some env vars
env: {
...getDefaultEnvironment(),
...this._serverParams.env
},
stdio: ['pipe', 'pipe', this._serverParams.stderr ?? 'inherit'],
shell: false,
windowsHide: process.platform === 'win32',
cwd: this._serverParams.cwd
});
this._process.on('error', error => {
reject(error);
this.onerror?.(error);
});
this._process.on('spawn', () => {
resolve();
});
this._process.on('close', _code => {
this._process = undefined;
this.onclose?.();
});
this._process.stdin?.on('error', error => {
this.onerror?.(error);
});
this._process.stdout?.on('data', chunk => {
this._readBuffer.append(chunk);
this.processReadBuffer();
});
this._process.stdout?.on('error', error => {
this.onerror?.(error);
});
if (this._stderrStream && this._process.stderr) {
this._process.stderr.pipe(this._stderrStream);
}
});
}
/**
* The stderr stream of the child process, if `StdioServerParameters.stderr` was set to "pipe" or "overlapped".
*
* If stderr piping was requested, a PassThrough stream is returned _immediately_, allowing callers to
* attach listeners before the start method is invoked. This prevents loss of any early
* error output emitted by the child process.
*/
get stderr() {
if (this._stderrStream) {
return this._stderrStream;
}
return this._process?.stderr ?? null;
}
/**
* The child process pid spawned by this transport.
*
* This is only available after the transport has been started.
*/
get pid() {
return this._process?.pid ?? null;
}
processReadBuffer() {
while (true) {
try {
const message = this._readBuffer.readMessage();
if (message === null) {
break;
}
this.onmessage?.(message);
}
catch (error) {
this.onerror?.(error);
}
}
}
async close() {
if (this._process) {
const processToClose = this._process;
this._process = undefined;
const closePromise = new Promise(resolve => {
processToClose.once('close', () => {
resolve();
});
});
try {
processToClose.stdin?.end();
}
catch {
// ignore
}
await Promise.race([closePromise, new Promise(resolve => setTimeout(resolve, 2000).unref())]);
if (processToClose.exitCode === null) {
try {
processToClose.kill('SIGTERM');
}
catch {
// ignore
}
await Promise.race([closePromise, new Promise(resolve => setTimeout(resolve, 2000).unref())]);
}
if (processToClose.exitCode === null) {
try {
processToClose.kill('SIGKILL');
}
catch {
// ignore
}
}
}
this._readBuffer.clear();
}
send(message) {
return new Promise(resolve => {
if (!this._process?.stdin) {
throw new Error('Not connected');
}
const json = serializeMessage(message);
if (this._process.stdin.write(json)) {
resolve();
}
else {
this._process.stdin.once('drain', resolve);
}
});
}
}
//# sourceMappingURL=stdio.js.map |