feat(deepseek): add support for Responses API and Chat Prefix Completion

.gitignore

@@ -6,6 +6,7 @@
 .env.*
 !.env.example
 /gophergate
+/gophergate_*
 /llm-proxy
 /llm-proxy-go
 *.log

README.md

@@ -5,7 +5,7 @@ A unified, high-performance LLM proxy gateway built in Go. It provides OpenAI-co
 ## Features
 
 - **Unified API:** OpenAI-compatible `/v1/chat/completions`, `/v1/images/generations`, `/v1/responses`, and `/v1/models` endpoints.
-  - The `/v1/responses` endpoint (OpenAI Responses API) is currently supported for OpenAI models only. Non-OpenAI providers (Gemini, DeepSeek, Moonshot, Grok, Ollama, Xiaomi) return a "not supported" response.
+  - The `/v1/responses` endpoint (OpenAI Responses API) is supported for OpenAI and DeepSeek models. Non-supported providers (Gemini, Moonshot, Grok, Ollama, Xiaomi) return a "not supported" response.
 - **Multi-Provider Support:**
   - **OpenAI:** GPT-4o, GPT-4o Mini, GPT-5, GPT-5.4, o1/o3/o4 reasoning models, DALL-E 2/3 image generation.
   - **Google Gemini:** Gemini 2.5 Flash/Pro, Gemini 3 Flash/Pro previews, Imagen 3 image generation.

internal/db/db.go

@@ -26,7 +26,7 @@ func Init(path string) (*DB, error) {
 	}
 
 	// Connect to SQLite
-	dsn := fmt.Sprintf("file:%s?_pragma=foreign_keys(1)", path)
+	dsn := fmt.Sprintf("file:%s?_pragma=foreign_keys(1)&_busy_timeout=5000", path)
 	db, err := sqlx.Connect("sqlite", dsn)
 	if err != nil {
 		return nil, fmt.Errorf("failed to connect to database: %w", err)

internal/models/models.go

@@ -32,6 +32,7 @@ type ChatMessage struct {
 	ToolCalls        []ToolCall  `json:"tool_calls,omitempty"`
 	Name             *string     `json:"name,omitempty"`
 	ToolCallID       *string     `json:"tool_call_id,omitempty"`
+	Prefix           *bool       `json:"prefix,omitempty"`
 }
 
 type ContentPart struct {
@@ -168,6 +169,7 @@ type UnifiedMessage struct {
 	ToolCalls        []ToolCall
 	Name             *string
 	ToolCallID       *string
+	Prefix           *bool
 }
 
 type UnifiedContentPart struct {

internal/providers/deepseek.go

@@ -257,9 +257,70 @@ func (p *DeepSeekProvider) ImageGeneration(ctx context.Context, req *models.Imag
 }
 
 func (p *DeepSeekProvider) Responses(ctx context.Context, req *models.ResponsesRequest) (*models.ResponsesResponse, error) {
-	return nil, fmt.Errorf("responses API not supported by deepseek")
+	stream := req.Stream != nil && *req.Stream
+	body := BuildOpenAIResponsesBody(req, stream)
+
+	resp, err := p.client.R().
+		SetContext(ctx).
+		SetHeader("Authorization", "Bearer "+p.apiKey).
+		SetBody(body).
+		Post(fmt.Sprintf("%s/responses", p.config.BaseURL))
+
+	if err != nil {
+		return nil, fmt.Errorf("responses request failed: %w", err)
+	}
+
+	if !resp.IsSuccess() {
+		msg := resp.String()
+		if msg == "" && resp.RawBody() != nil {
+			if bodyBytes, err := io.ReadAll(resp.RawBody()); err == nil {
+				msg = string(bodyBytes)
+			}
+		}
+		return nil, fmt.Errorf("DeepSeek Responses API error (%d): %s", resp.StatusCode(), msg)
+	}
+
+	var respJSON map[string]interface{}
+	if err := json.Unmarshal(resp.Body(), &respJSON); err != nil {
+		return nil, fmt.Errorf("failed to parse responses response: %w", err)
+	}
+
+	return ParseOpenAIResponsesResponse(respJSON, req.Model)
 }
 
 func (p *DeepSeekProvider) ResponsesStream(ctx context.Context, req *models.ResponsesRequest) (<-chan *models.ResponsesStreamChunk, error) {
-	return nil, fmt.Errorf("responses API not supported by deepseek")
+	body := BuildOpenAIResponsesBody(req, true)
+
+	resp, err := p.client.R().
+		SetContext(ctx).
+		SetHeader("Authorization", "Bearer "+p.apiKey).
+		SetBody(body).
+		SetDoNotParseResponse(true).
+		Post(fmt.Sprintf("%s/responses", p.config.BaseURL))
+
+	if err != nil {
+		return nil, fmt.Errorf("responses stream request failed: %w", err)
+	}
+
+	if !resp.IsSuccess() {
+		msg := resp.String()
+		if msg == "" && resp.RawBody() != nil {
+			if bodyBytes, err := io.ReadAll(resp.RawBody()); err == nil {
+				msg = string(bodyBytes)
+			}
+		}
+		return nil, fmt.Errorf("DeepSeek Responses API error (%d): %s", resp.StatusCode(), msg)
+	}
+
+	ch := make(chan *models.ResponsesStreamChunk)
+
+	go func() {
+		defer close(ch)
+		err := StreamOpenAIResponses(resp.RawBody(), ch)
+		if err != nil {
+			fmt.Printf("DeepSeek Responses stream error: %v\n", err)
+		}
+	}()
+
+	return ch, nil
 }

internal/providers/helpers.go

@@ -158,6 +158,9 @@ func MessagesToOpenAIJSON(messages []models.UnifiedMessage) ([]interface{}, erro
 		if m.Name != nil {
 			msg["name"] = *m.Name
 		}
+		if m.Prefix != nil {
+			msg["prefix"] = *m.Prefix
+		}
 		result = append(result, msg)
 	}
 	return result, nil

internal/server/server.go

@@ -700,6 +700,7 @@ func (s *Server) handleChatCompletions(c *gin.Context) {
 			ToolCalls:        msg.ToolCalls,
 			Name:             msg.Name,
 			ToolCallID:       msg.ToolCallID,
+			Prefix:           msg.Prefix,
 		}
 
 		// Handle multimodal content