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|
import type { Inspector, InspectorListener } from ".";
import { JSC } from "..";
import { WebSocket } from "ws";
export type WebSocketInspectorOptions = {
url?: string | URL;
listener?: InspectorListener;
};
/**
* An inspector that communicates with a debugger over a WebSocket.
*/
export class WebSocketInspector implements Inspector {
#url?: URL;
#webSocket?: WebSocket;
#requestId: number;
#pendingRequests: Map<number, (result: unknown) => void>;
#pendingMessages: string[];
#listener: InspectorListener;
constructor({ url, listener }: WebSocketInspectorOptions) {
this.#url = url ? new URL(url) : undefined;
this.#listener = listener ?? {};
this.#requestId = 1;
this.#pendingRequests = new Map();
this.#pendingMessages = [];
}
start(url?: string | URL): void {
if (url) {
this.#url = new URL(url);
}
if (this.#url) {
this.#connect();
}
}
#connect(): void {
if (!this.#url) {
return;
}
this.#webSocket?.close();
let webSocket: WebSocket;
try {
console.log("[jsc] connecting", this.#url.href);
webSocket = new WebSocket(this.#url, {
headers: {
"Ref-Event-Loop": "0",
},
});
} catch (error) {
this.#close(unknownToError(error));
return;
}
webSocket.addEventListener("open", () => {
console.log("[jsc] connected");
for (const message of this.#pendingMessages) {
this.#send(message);
}
this.#pendingMessages.length = 0;
this.#listener["Inspector.connected"]?.();
});
webSocket.addEventListener("message", ({ data }) => {
if (typeof data === "string") {
this.accept(data);
}
});
webSocket.addEventListener("error", event => {
console.log("[jsc] error", event);
this.#close(unknownToError(event));
});
webSocket.addEventListener("unexpected-response", () => {
console.log("[jsc] unexpected-response");
this.#close(new Error("WebSocket upgrade failed"));
});
webSocket.addEventListener("close", ({ code, reason }) => {
console.log("[jsc] closed", code, reason);
if (code === 1001) {
this.#close();
} else {
this.#close(new Error(`WebSocket closed: ${code} ${reason}`.trimEnd()));
}
});
this.#webSocket = webSocket;
}
send<M extends keyof JSC.RequestMap & keyof JSC.ResponseMap>(
method: M,
params?: JSC.RequestMap[M] | undefined,
): Promise<JSC.ResponseMap[M]> {
const id = this.#requestId++;
const request = { id, method, params };
console.log("[jsc] -->", request);
return new Promise((resolve, reject) => {
const done = (result: any) => {
this.#pendingRequests.delete(id);
if (result instanceof Error) {
reject(result);
} else {
resolve(result);
}
};
this.#pendingRequests.set(id, done);
this.#send(JSON.stringify(request));
});
}
#send(message: string): void {
if (this.#webSocket) {
const { readyState } = this.#webSocket!;
if (readyState === WebSocket.OPEN) {
this.#webSocket.send(message);
}
return;
}
if (!this.#pendingMessages.includes(message)) {
this.#pendingMessages.push(message);
}
}
accept(message: string): void {
let event: JSC.Event | JSC.Response;
try {
event = JSON.parse(message);
} catch (error) {
console.error("Failed to parse message:", message);
return;
}
console.log("[jsc] <--", event);
if ("id" in event) {
const { id } = event;
const resolve = this.#pendingRequests.get(id);
if (!resolve) {
console.error(`Failed to accept response for unknown ID ${id}:`, event);
return;
}
this.#pendingRequests.delete(id);
if ("error" in event) {
const { error } = event;
const { message } = error;
resolve(new Error(message));
} else {
const { result } = event;
resolve(result);
}
} else {
const { method, params } = event;
try {
// @ts-ignore
this.#listener[method]?.(params);
} catch (error) {
console.error(`Failed to accept ${method} event:`, error);
return;
}
}
}
get closed(): boolean {
if (!this.#webSocket) {
return true;
}
const { readyState } = this.#webSocket;
switch (readyState) {
case WebSocket.CLOSED:
case WebSocket.CLOSING:
return true;
}
return false;
}
close(code?: number, reason?: string): void {
this.#webSocket?.close(code ?? 1001, reason);
}
#close(error?: Error): void {
try {
this.#listener["Inspector.disconnected"]?.(error);
} finally {
for (const resolve of this.#pendingRequests.values()) {
resolve(error ?? new Error("WebSocket closed"));
}
this.#pendingRequests.clear();
}
}
}
function unknownToError(input: unknown): Error {
if (input instanceof Error) {
return input;
}
if (typeof input === "object" && input !== null && "message" in input) {
const { message } = input;
return new Error(`${message}`);
}
return new Error(`${input}`);
}
|
