pairing-dial.ts

1// The WebSocket seam every relay-facing Peach flow shares.2//3// Production wires the real `WebSocket`; tests inject a fake. One binary4// message per frame. Nothing here touches chrome or the vault, because vault5// adoption runs before a vault exists at all.67/**8 * Minimal binary WebSocket seam. One binary message per frame.9 */10export interface PairingSocket {11  send(bytes: Uint8Array): void;12  /** Resolves with the next inbound binary frame, or rejects on close. */13  receive(): Promise<Uint8Array>;14  close(): void;15  /** True if the socket closed before the next frame arrived. */16  closedBeforeFrame(): boolean;17}1819/** Relay pairing uses this binary socket seam over `wss://`. */20export function openRelayPairingSocket(url: string): Promise<PairingSocket> {21  return new Promise((resolve, reject) => {22    let ws: WebSocket;23    try {24      ws = new WebSocket(url);25    } catch (err) {26      reject(err instanceof Error ? err : new Error("websocket open failed"));27      return;28    }29    ws.binaryType = "arraybuffer";3031    const inbox: Uint8Array[] = [];32    const readers: Array<{ resolve: (b: Uint8Array) => void; reject: (e: Error) => void }> = [];33    let opened = false;34    let closed = false;35    // True iff the socket closed with no frame delivered for the pending read —36    // the wrong/expired-code signal (the listener sends no error frame).37    let sawCloseBeforeFrame = false;3839    ws.onopen = () => {40      opened = true;41      resolve(sock);42    };43    ws.onmessage = (ev: MessageEvent) => {44      const bytes = new Uint8Array(ev.data as ArrayBuffer);45      const r = readers.shift();46      if (r) { sawCloseBeforeFrame = false; r.resolve(bytes); }47      else inbox.push(bytes);48    };49    ws.onerror = () => {50      if (!opened) reject(new Error("websocket connection failed"));51    };52    ws.onclose = () => {53      closed = true;54      if (readers.length) {55        sawCloseBeforeFrame = true;56        while (readers.length) readers.shift()!.reject(new Error("socket closed"));57      }58      if (!opened) reject(new Error("socket closed before open"));59    };6061    const sock: PairingSocket = {62      send(bytes: Uint8Array) { ws.send(bytes as Uint8Array<ArrayBuffer>); },63      receive(): Promise<Uint8Array> {64        const queued = inbox.shift();65        if (queued) { sawCloseBeforeFrame = false; return Promise.resolve(queued); }66        if (closed) { sawCloseBeforeFrame = true; return Promise.reject(new Error("socket closed")); }67        return new Promise<Uint8Array>((res, rej) => readers.push({ resolve: res, reject: rej }));68      },69      close() { try { ws.close(); } catch { /* ignore */ } },70      closedBeforeFrame() { return sawCloseBeforeFrame; },71    };72  });73}