feat(ai-assist): SSE streaming + IPC handler

AiProviders.completeStream() — async iterable over provider chunks. - OpenAI-style (openai, ollama, lmstudio, *-compatible): parses SSE data: {choices:[{delta:{content}}]} payloads. - Anthropic: parses event: content_block_delta with delta.text. - Honours caller AbortSignal + internal timeout via AbortController. - shared parseSseStream() helper handles [DONE] sentinel, partial lines across chunk boundaries, reader.releaseLock() in finally. main.js IPC: - 'ai-assist-stream:start' (send) registers a per-requestId entry in a Map with an AbortController, iterates completeStream, and forwards each chunk via 'ai-assist-stream:chunk' (send). - 'ai-assist-stream:cancel' (send) aborts the in-flight request. - Terminal 'done' or 'error' (with code+message) is sent after each stream; renderer can correlate by requestId. preload.js exposes aiAssist.{start, cancel, onChunk, onDone, onError}. 5 new tests covering OpenAI delta parsing, Anthropic content_block_delta parsing, and three synchronous-error paths (no fetch, no messages, missing key). Amit Haridas
2026-10-01 17:29:29 +05:30 · 2026-09-30 20:04:32 +05:30
parent cb0b2eac3d
commit 1a25669967
4 changed files with 375 additions and 0 deletions
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+/**
+ * @jest-environment node
+ *
+ * AiProviders.completeStream — minimal coverage of the SSE parser.
+ * Provider-specific shapes (OpenAI delta.content, Anthropic content_block_delta)
+ * are exercised via the parseData callback the helpers accept.
+ */
+
+/* global ReadableStream, Response */
+
+const { completeStream, AiProviderError } = require('../src/main/AiProviders');
+
+function makeSseResponse(lines) {
+  const body = lines.join('\n') + '\n';
+  const stream = new ReadableStream({
+    start(controller) {
+      controller.enqueue(new TextEncoder().encode(body));
+      controller.close();
+    },
+  });
+  return new Response(stream, { status: 200 });
+}
+
+async function collect(iterable) {
+  const out = [];
+  for await (const chunk of iterable) out.push(chunk);
+  return out;
+}
+
+describe('AiProviders.completeStream', () => {
+  test('openai-style: yields delta.content per chunk, stops at [DONE]', async () => {
+    const fetchImpl = jest
+      .fn()
+      .mockResolvedValue(
+        makeSseResponse([
+          'data: {"choices":[{"delta":{"content":"Hello"}}]}',
+          'data: {"choices":[{"delta":{"content":", world"}}]}',
+          'data: {"choices":[{"delta":{"content":"!"}}]}',
+          'data: [DONE]',
+        ])
+      );
+
+    const chunks = await collect(
+      completeStream(
+        {
+          provider: 'openai',
+          apiKey: 'sk-test',
+          messages: [{ role: 'user', content: 'hi' }],
+        },
+        { fetchImpl }
+      )
+    );
+
+    expect(chunks.join('')).toBe('Hello, world!');
+  });
+
+  test('anthropic-style: yields delta.text only from content_block_delta events', async () => {
+    const fetchImpl = jest
+      .fn()
+      .mockResolvedValue(
+        makeSseResponse([
+          'event: message_start',
+          'data: {"type":"message_start","message":{}}',
+          '',
+          'event: content_block_start',
+          'data: {"type":"content_block_start"}',
+          '',
+          'event: content_block_delta',
+          'data: {"type":"content_block_delta","delta":{"text":"Hi"}}',
+          '',
+          'event: content_block_delta',
+          'data: {"type":"content_block_delta","delta":{"text":" there"}}',
+          '',
+          'data: [DONE]',
+        ])
+      );
+
+    const chunks = await collect(
+      completeStream(
+        {
+          provider: 'anthropic',
+          apiKey: 'sk-test',
+          messages: [{ role: 'user', content: 'hi' }],
+        },
+        { fetchImpl }
+      )
+    );
+
+    expect(chunks.join('')).toBe('Hi there');
+  });
+
+  test('throws AiProviderError when no fetch implementation is available', async () => {
+    const drain = async () => {
+      // eslint-disable-next-line no-unused-vars
+      for await (const _chunk of completeStream(
+        { provider: 'openai', apiKey: 'x', messages: [{ role: 'user', content: 'h' }] },
+        { fetchImpl: null }
+      )) {
+        // drain
+      }
+    };
+    await expect(drain()).rejects.toBeInstanceOf(AiProviderError);
+  });
+
+  test('throws on empty messages', async () => {
+    const drain = async () => {
+      // eslint-disable-next-line no-unused-vars
+      for await (const _chunk of completeStream(
+        { provider: 'openai', apiKey: 'x', messages: [] },
+        { fetchImpl: jest.fn() }
+      )) {
+        // drain
+      }
+    };
+    await expect(drain()).rejects.toThrow(/No messages/);
+  });
+
+  test('throws on missing API key for branded providers', async () => {
+    const drain = async () => {
+      // eslint-disable-next-line no-unused-vars
+      for await (const _chunk of completeStream(
+        { provider: 'openai', apiKey: '', messages: [{ role: 'user', content: 'h' }] },
+        { fetchImpl: jest.fn() }
+      )) {
+        // drain
+      }
+    };
+    await expect(drain()).rejects.toThrow(/API key/);
+  });
+});