### What problem does this PR solve?
Fixes#15840.
The Go HTTP server sets `WriteTimeout: 120s`, which also applies to
long-lived SSE responses. Existing Go streaming handlers did not clear
the per-response write deadline, so streams that run longer than the
server timeout can be terminated mid-response.
This PR adds a small handler helper that clears the response write
deadline for SSE requests and calls it only in existing Go streaming
branches:
- conversation completion streaming
- provider chat streaming
- provider transcription streaming
- provider speech streaming
The global server `WriteTimeout` remains unchanged for non-streaming
requests.
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
### Test plan
- `/root/go/bin/go test ./internal/handler -run
TestDisableWriteDeadlineForSSEAllowsLongLivedStream -count=1`
- `/root/go/bin/go test ./internal/handler -count=1`
Implements POST /api/v1/searchbots/ask in Go with streaming SSE,
citations, and think-tag processing. 23 files, 90+ unit tests.
---------
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
## What problem does this PR solve?
Implements `POST /api/v1/searchbots/retrieval_test` in the Go API
server, aligning with the Python `bot_api.py` counterpart. Also applies
security hardening and consistency fixes discovered during CTO-level
code review:
- **Missing endpoint**: `retrieval_test` was not available in Go,
requiring Python fallback
- **Security**: Both `chunkHandler` and `searchBotHandler` leaked
`err.Error()` to API consumers
- **Python alignment**: Default values, empty question handling, and
`top_k <= 0` validation differed from Python behavior
- **Test gaps**: `chunkHandler.RetrievalTest` had zero unit tests;
several edge cases uncovered
## Type of change
- [x] New Feature (non-breaking change which adds functionality)
- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] Refactoring
## Summary
### New Endpoint
- `POST /api/v1/searchbots/retrieval_test` — retrieval test with full
field support (page, size, top_k, use_kg, cross_languages, keyword,
similarity_threshold, vector_similarity_weight)
### New Type
- `common.StringSlice` — JSON type that accepts both `"kb1"` and
`["kb1", "kb2"]`, matching Python API flexibility
### Security
- Both `searchBotHandler` and `chunkHandler` now use `common.Warn()` +
generic error messages instead of leaking `err.Error()` to API consumers
- All error responses include consistent `"data": nil` shape
- `chunkHandler.RetrievalTest` uses interface-based DI (`chunkService`)
to enable testability
### Python Alignment
- Handler-level defaults align with Python `bot_api.py` (page=1,
size=30, top_k=1024, similarity_threshold=0.0,
vector_similarity_weight=0.3)
- `top_k <= 0` validation matching Python behavior
- Empty/whitespace question returns 200 + empty result (matches
`chunk_api.py`)
- `chunkHandler` `Datasets` field uses `common.StringSlice` for
string-or-array flexibility
### Refactoring
- `ChunkServiceIface` → `ChunkRetriever`, `chunkSvcIface` →
`chunkService` (Go-conventional naming)
- Extracted `applyRetrievalDefaults`, `toRetrievalServiceRequest` from
handler body
- Regex moved to package-level var in `parseRelatedQuestions`
- `service.RetrievalTestRequest.Datasets` type changed to
`common.StringSlice`
- `chunkHandler` now uses consumer-side interface for DI
### Tests
- 37 unit tests across both handlers: auth, validation, defaults,
StringSlice edge cases, empty/whitespace KbID, service errors, JSON
format, `top_k <= 0`, field mapping verification
## Files Changed
| File | Change |
|------|--------|
| `cmd/server_main.go` | Wire new handler + chunkService +
difyRetrievalHandler |
| `internal/common/json_types.go` | New StringSlice type |
| `internal/common/json_types_test.go` | StringSlice tests |
| `internal/handler/chunk.go` | Interface-based DI, security, Python
alignment, defaults |
| `internal/handler/chunk_test.go` | New — 9 comprehensive tests |
| `internal/handler/searchbot.go` | New endpoint + refactoring + `top_k
<= 0` validation |
| `internal/handler/searchbot_test.go` | 18 tests covering all edge
cases |
| `internal/router/router.go` | Register new route +
difyRetrievalHandler |
| `internal/service/chunk.go` | Datasets type → StringSlice, Question
binding relaxed |
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
