refactor: 收口前端 SSE 传输层

src/services/sseStream.test.ts

@@ -0,0 +1,98 @@
+import { expect, test } from 'vitest';
+
+import { readSseJsonStream, readSseStream } from './sseStream';
+
+function createChunkedStreamResponse(chunks: Uint8Array[]) {
+  const stream = new ReadableStream<Uint8Array>({
+    start(controller) {
+      for (const chunk of chunks) {
+        controller.enqueue(chunk);
+      }
+      controller.close();
+    },
+  });
+
+  return new Response(stream, {
+    headers: {
+      'Content-Type': 'text/event-stream; charset=utf-8',
+    },
+  });
+}
+
+test('readSseJsonStream flushes decoder tail and handles CRLF boundaries', async () => {
+  const encoder = new TextEncoder();
+  const prefix = encoder.encode('event: reply_delta\r\ndata: {"text":"');
+  const replyBytes = encoder.encode('溪上春风');
+  const suffix = encoder.encode('"}\r\n\r\n');
+  const splitIndex = replyBytes.length - 1;
+  const events: Array<{ eventName: string; parsed: Record<string, unknown> }> =
+    [];
+
+  await readSseJsonStream(
+    createChunkedStreamResponse([
+      new Uint8Array([...prefix, ...replyBytes.slice(0, splitIndex)]),
+      new Uint8Array([...replyBytes.slice(splitIndex), ...suffix]),
+    ]),
+    ({ eventName, parsed }) => {
+      events.push({ eventName, parsed });
+    },
+  );
+
+  expect(events).toEqual([
+    {
+      eventName: 'reply_delta',
+      parsed: { text: '溪上春风' },
+    },
+  ]);
+});
+
+test('readSseJsonStream skips malformed json and keeps valid LF events', async () => {
+  const encoder = new TextEncoder();
+  const events: Array<{ eventName: string; parsed: Record<string, unknown> }> =
+    [];
+
+  await readSseJsonStream(
+    createChunkedStreamResponse([
+      encoder.encode(
+        'event: malformed\ndata: not-json\n\n' +
+          'event: ready\ndata: {"value":7}\n\n',
+      ),
+    ]),
+    ({ eventName, parsed }) => {
+      events.push({ eventName, parsed });
+    },
+  );
+
+  expect(events).toEqual([
+    {
+      eventName: 'ready',
+      parsed: { value: 7 },
+    },
+  ]);
+});
+
+test('readSseStream can stop early and cancel the reader', async () => {
+  const encoder = new TextEncoder();
+  let cancelled = false;
+  const stream = new ReadableStream<Uint8Array>({
+    start(controller) {
+      controller.enqueue(
+        encoder.encode(
+          'event: first\ndata: one\n\n' + 'event: second\ndata: two\n\n',
+        ),
+      );
+    },
+    cancel() {
+      cancelled = true;
+    },
+  });
+  const events: string[] = [];
+
+  await readSseStream(new Response(stream), ({ eventName }) => {
+    events.push(eventName);
+    return false;
+  });
+
+  expect(events).toEqual(['first']);
+  expect(cancelled).toBe(true);
+});