(options: ClientOptions)
| 37 | // method on the returned stub queues until the WebSocket reaches |
| 38 | // readyState OPEN; capnweb's transport handles that. |
| 39 | export function createSyncClient(options: ClientOptions): SyncClient { |
| 40 | const WS = options.WebSocketImpl ?? WebSocket; |
| 41 | const ws = new WS(options.url); |
| 42 | // The WebSocket cast crosses two type boundaries: the runtime |
| 43 | // ws (node `ws` package or global) is structurally compatible |
| 44 | // with capnweb's expected globalThis.WebSocket but TS can't |
| 45 | // bridge the nominal types. The RpcStub cast names the remote |
| 46 | // interface so the Proxy returned downstream is strongly typed. |
| 47 | const stub = newWebSocketRpcSession(ws as unknown as globalThis.WebSocket) as RpcStub<SyncRPC>; |
| 48 | // capnweb's RpcStub is a Proxy that exposes the remote interface |
| 49 | // as if it were local. We wrap it so callers see SyncClient |
| 50 | // (= SyncRPC + close). |
| 51 | const onEvent = options.onRPCEvent; |
| 52 | return new Proxy(stub, { |
| 53 | get(target, prop, receiver) { |
| 54 | if (prop === "close") { |
| 55 | return async () => { |
| 56 | // Dispose the root stub first — per capnweb's docs this |
| 57 | // is the documented way to close a session and lets the |
| 58 | // RPC layer send a clean abort frame before the transport |
| 59 | // dies. ws.close() below is belt-and-braces. |
| 60 | try { |
| 61 | (target as unknown as Disposable)[Symbol.dispose]?.(); |
| 62 | } catch { |
| 63 | // already disposed; idempotent |
| 64 | } |
| 65 | await new Promise<void>((resolve) => { |
| 66 | const w = ws as unknown as { readyState: number; close: () => void }; |
| 67 | if (w.readyState >= 2) { |
| 68 | resolve(); |
| 69 | return; |
| 70 | } |
| 71 | (ws as unknown as EventTarget).addEventListener("close", () => resolve(), { |
| 72 | once: true, |
| 73 | }); |
| 74 | w.close(); |
| 75 | // Belt-and-braces: if `close` never fires (the socket |
| 76 | // was already torn down) the timeout breaks the await. |
| 77 | setTimeout(resolve, 200); |
| 78 | }); |
| 79 | }; |
| 80 | } |
| 81 | const value = Reflect.get(target, prop, receiver); |
| 82 | if (onEvent === undefined || typeof prop !== "string") return value; |
| 83 | // Capnweb's Proxy returns a callable RpcPromise/RpcStub for |
| 84 | // every string property. Wrap the call to time it and fire |
| 85 | // onRPCEvent. The wrapped value still behaves like an |
| 86 | // RpcPromise (thenable + property-access for pipelining) for |
| 87 | // calls that return synchronously-pipelined values; we only |
| 88 | // measure the awaited terminal call. |
| 89 | return (...args: unknown[]) => { |
| 90 | const start = Date.now(); |
| 91 | const result = (value as (...a: unknown[]) => unknown)(...args); |
| 92 | // For non-thenable returns (streams), fire the event |
| 93 | // immediately with ok=true. The caller may still throw |
| 94 | // while reading the stream; observability for that path |
| 95 | // belongs to the caller. |
| 96 | if (result && typeof (result as { then?: unknown }).then === "function") { |
no outgoing calls
no test coverage detected