mirror of
https://github.com/MBombeck/HealthLog.git
synced 2026-11-12 06:06:10 +00:00
The Coach chat route had three identical `new ReadableStream({
start(controller) { try { ... } finally { controller.close(); } } })`
blocks (refusal / provider-error / happy path), differing only in
which frames they enqueued. Extract the boilerplate into
`src/lib/sse/create-stream.ts` so the v1.5 iOS streaming endpoints
inherit the same try/finally close semantics without copy-paste.
The helper accepts sync or async emit callbacks; the controller is
always closed in `finally` so a thrown emit never hangs the response.
Three unit tests pin the sync, async, and throw paths.
Closes Sr-H2.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
44 lines
1.6 KiB
TypeScript
44 lines
1.6 KiB
TypeScript
/**
|
|
* v1.4.22 W5 reconcile (Sr-H2) — shared `ReadableStream` constructor
|
|
* for Server-Sent-Events handlers.
|
|
*
|
|
* The Coach chat route used to construct three separate
|
|
* `new ReadableStream({ start(controller) { try { … } finally {
|
|
* controller.close(); } } })` blocks — one for the refusal path, one
|
|
* for the provider-error path, one for the happy path. Each emitted a
|
|
* different mix of frames but the construction shape was identical.
|
|
*
|
|
* Extract the boilerplate so future SSE consumers (the v1.5 iOS
|
|
* daily-briefing live-regenerate endpoint is the next one) inherit the
|
|
* same try/finally close semantics without copy-paste.
|
|
*
|
|
* The `emit` callback receives the controller and is awaited inside
|
|
* the `start` body. Any error inside the callback re-enters the
|
|
* `finally` and closes the stream cleanly so the client sees the
|
|
* connection terminate (and never sees a hung response).
|
|
*/
|
|
|
|
export interface SseController<T = Uint8Array> {
|
|
enqueue: (chunk: T) => void;
|
|
}
|
|
|
|
/**
|
|
* Build a `ReadableStream<Uint8Array>` whose `start` callback runs the
|
|
* supplied `emit` function inside a try/finally that always closes the
|
|
* controller. Use the returned stream with the standard SSE response
|
|
* headers (`Content-Type: text/event-stream`, `Cache-Control: no-cache`).
|
|
*/
|
|
export function createSseStream(
|
|
emit: (controller: SseController) => void | Promise<void>,
|
|
): ReadableStream<Uint8Array> {
|
|
return new ReadableStream<Uint8Array>({
|
|
async start(controller) {
|
|
try {
|
|
await emit(controller);
|
|
} finally {
|
|
controller.close();
|
|
}
|
|
},
|
|
});
|
|
}
|