77 lines
1.9 KiB
TypeScript
77 lines
1.9 KiB
TypeScript
import { Transport } from "../shared/transport.js";
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import { JSONRPCMessage, JSONRPCMessageSchema } from "../types.js";
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const SUBPROTOCOL = "mcp";
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/**
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* Client transport for WebSocket: this will connect to a server over the WebSocket protocol.
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*/
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export class WebSocketClientTransport implements Transport {
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private _socket?: WebSocket;
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private _url: URL;
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onclose?: () => void;
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onerror?: (error: Error) => void;
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onmessage?: (message: JSONRPCMessage) => void;
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constructor(url: URL) {
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this._url = url;
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}
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start(): Promise<void> {
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if (this._socket) {
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throw new Error(
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"WebSocketClientTransport already started! If using Client class, note that connect() calls start() automatically.",
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);
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}
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return new Promise((resolve, reject) => {
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this._socket = new WebSocket(this._url, SUBPROTOCOL);
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this._socket.onerror = (event) => {
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const error =
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"error" in event
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? (event.error as Error)
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: new Error(`WebSocket error: ${JSON.stringify(event)}`);
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reject(error);
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this.onerror?.(error);
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};
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this._socket.onopen = () => {
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resolve();
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};
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this._socket.onclose = () => {
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this.onclose?.();
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};
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this._socket.onmessage = (event: MessageEvent) => {
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let message: JSONRPCMessage;
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try {
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message = JSONRPCMessageSchema.parse(JSON.parse(event.data));
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} catch (error) {
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this.onerror?.(error as Error);
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return;
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}
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this.onmessage?.(message);
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};
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});
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}
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async close(): Promise<void> {
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this._socket?.close();
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}
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send(message: JSONRPCMessage): Promise<void> {
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return new Promise((resolve, reject) => {
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if (!this._socket) {
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reject(new Error("Not connected"));
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return;
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}
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this._socket?.send(JSON.stringify(message));
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resolve();
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});
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}
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}
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