### What problem does this PR solve?
```
RAGFlow(user)> embed text 'what is rag' 'who are you' with 'embedding-3@test@zhipu-ai' dimension 16;
+-----------+-------+
| dimension | index |
+-----------+-------+
| 16 | 0 |
| 16 | 1 |
+-----------+-------+
RAGFlow(user)> rerank query 'what is rag' document 'rag is retrieval augment generation' 'rag need llm' 'famous rag project includes ragflow' with 'rerank@test@zhipu-ai' top 2;
+-------+-----------------+
| index | relevance_score |
+-------+-----------------+
| 0 | 1 |
| 2 | 0.99999976 |
+-------+-----------------+
```
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
Signed-off-by: Jin Hai <haijin.chn@gmail.com>
### What problem does this PR solve?
1. **Fix Global State Pollution in Local Providers (Critical Bug):** -
Resolved a severe concurrency and architecture issue in
`model_service.go`. Previously, `ListSupportedModels` would permanently
overwrite the global provider singleton with a localized URL instance
(`driver.NewInstance`). This caused cross-request contamination in
multi-tenant environments.
- Fixed `CheckProviderConnection` for local models (LM Studio, vLLM,
Ollama). It now properly creates a localized driver copy and injects the
`base_url` before testing the connection, entirely eliminating the
false-positive `missing base URL` error without polluting the global
state.
2. **Implement `VolcEngine` Embeddings:** - Fully implemented the
`Encode` method for the `volcengine` provider, enabling text embedding
capabilities for VolcEngine models.
3. **Enhance Region Validation in `SiliconFlow`:** - Added a strict
empty string check (`*apiConfig.Region != ""`) alongside the existing
`nil` check when parsing regions. This ensures that if an empty string
is passed, the system safely falls back to the `"default"` region,
preventing malformed URL requests and `unsupported protocol scheme`
errors.
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
1. **Implement `OpenRouter` Provider:** Fully support OpenRouter AI
models (e.g., `gemma`, `minimax`). Includes robust handling of
Server-Sent Events (SSE) streams, error event interception, and proper
parsing of both `reasoning_content` and standard `content`.
2. **Fix BaseURL Resolution Bug:** Fixed a critical edge case in region
configuration parsing. Added a strict empty string check
(`*apiConfig.Region != ""`) alongside the `nil` check. This ensures that
if the UI passes an empty string, the system correctly falls back to the
`"default"` region, preventing `unsupported protocol scheme ""` errors
during HTTP requests.
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Three Go drivers had `CheckConnection` returning a hardcoded `no such
method` error, even though each one already has a working `ListModels`
that hits the configured base URL with the configured API key. So the
"Check connection" button in the model provider UI always failed for
these three providers, even when the underlying setup was fine.
Affected drivers:
- `internal/entity/models/ollama.go`
- `internal/entity/models/lmstudio.go`
- `internal/entity/models/vllm.go`
This is a real user-facing gap because Ollama and LM Studio are two of
the most popular local LLM runners, and vLLM is widely used for
self-hosted deployments.
### What this PR includes
For each of the three drivers, replace the stub with a small
implementation that calls `ListModels` and returns its error:
```go
func (o *OllamaModel) CheckConnection(apiConfig *APIConfig) error {
_, err := o.ListModels(apiConfig)
return err
}
```
This is the exact pattern that xai, moonshot, deepseek, aliyun, and
gitee already use for the same method.
No JSON change. No factory change. No interface change.
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
### How was this tested?
- `go build ./internal/entity/models/...` in a clean go 1.25 image (the
go.mod minimum) returns exit 0.
- The full ModelDriver interface still resolves on each driver
(NewInstance, Name, ChatWithMessages, ChatStreamlyWithSender, Encode,
Rerank, ListModels, Balance, CheckConnection).
- Pattern parity with the existing xai, moonshot, deepseek, aliyun, and
gitee CheckConnection methods.
Closes#14609
### What problem does this PR solve?
implement `lm-studio` provider
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
- [x] Refactoring
