feat: implement POST /api/v1/searchbots/related_questions API (#15639)

## Summary Implement the `POST /api/v1/searchbots/related_questions` endpoint in Go, generating related search questions via LLM. ### Changes - **New**: `internal/handler/related_questions.go` — Handler with injectable LLM interface, prompt constant, and response parsing - **New**: `internal/handler/related_questions_test.go` — 9 tests (4 handler + 5 parse) - **Modified**: `internal/router/router.go` — Added route + `RelatedQuestionsHandler` to struct - **Modified**: `cmd/server_main.go` — Wired handler with `SearchService` and `ModelProviderService` ### Testing All 9 tests pass: ``` === RUN TestRelatedQuestionsHandler_Success --- PASS === RUN TestRelatedQuestionsHandler_EmptyResponse --- PASS === RUN TestRelatedQuestionsHandler_LLMFailure --- PASS === RUN TestRelatedQuestionsHandler_MissingQuestion --- PASS === RUN TestParseRelatedQuestions_Standard --- PASS === RUN TestParseRelatedQuestions_Empty --- PASS === RUN TestParseRelatedQuestions_NoNumberedLines --- PASS === RUN TestParseRelatedQuestions_MixedContent --- PASS === RUN TestParseRelatedQuestions_MultiDigit --- PASS ``` Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> --------- Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-13 16:38:26 +08:00 · 2026-06-04 19:13:58 +08:00
parent 6143205b37
commit e627f5d8c5
4 changed files with 470 additions and 3 deletions
--- a/cmd/server_main.go
+++ b/cmd/server_main.go
@@ -212,9 +212,14 @@ func startServer(config *server.Config) {
 	skillSearchHandler := handler.NewSkillSearchHandler(docEngine)
 	providerHandler := handler.NewProviderHandler(userService, modelProviderService)
 	agentHandler := handler.NewAgentHandler(service.NewAgentService(), fileService)
+	relatedQuestionsHandler := handler.NewSearchbotHandler(
+		searchService,
+		tenantService,
+		&handler.SearchbotRealLLM{Svc: modelProviderService},
+	)

 	// Initialize router
-	r := router.NewRouter(authHandler, userHandler, tenantHandler, documentHandler, datasetsHandler, systemHandler, knowledgebaseHandler, chunkHandler, llmHandler, chatHandler, chatSessionHandler, connectorHandler, searchHandler, fileHandler, memoryHandler, mcpHandler, skillSearchHandler, providerHandler, agentHandler)
+	r := router.NewRouter(authHandler, userHandler, tenantHandler, documentHandler, datasetsHandler, systemHandler, knowledgebaseHandler, chunkHandler, llmHandler, chatHandler, chatSessionHandler, connectorHandler, searchHandler, fileHandler, memoryHandler, mcpHandler, skillSearchHandler, providerHandler, agentHandler, relatedQuestionsHandler)

 	// Create Gin engine
 	ginEngine := gin.New()
--- a/internal/handler/searchbot.go
+++ b/internal/handler/searchbot.go
@@ -0,0 +1,229 @@
+//
+//  Copyright 2026 The InfiniFlow Authors. All Rights Reserved.
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+//
+
+package handler
+
+import (
+	"net/http"
+	"regexp"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+
+	"ragflow/internal/common"
+	"ragflow/internal/entity"
+	modelModule "ragflow/internal/entity/models"
+	"ragflow/internal/service"
+
+	"go.uber.org/zap"
+)
+
+// searchbotLLM is the interface for LLM calls used by SearchbotHandler.
+type searchbotLLM interface {
+	Chat(tenantID, modelID string, messages []modelModule.Message, config *modelModule.ChatConfig) (*modelModule.ChatResponse, error)
+}
+
+// SearchbotRealLLM wraps ModelProviderService to implement searchbotLLM.
+type SearchbotRealLLM struct {
+	Svc *service.ModelProviderService
+}
+
+func (r *SearchbotRealLLM) Chat(tenantID, modelID string, messages []modelModule.Message, config *modelModule.ChatConfig) (*modelModule.ChatResponse, error) {
+	chatModel, err := r.Svc.GetChatModel(tenantID, modelID)
+	if err != nil {
+		return nil, err
+	}
+	return chatModel.ModelDriver.ChatWithMessages(*chatModel.ModelName, messages, chatModel.APIConfig, config)
+}
+
+// SearchbotRequest is the request body for POST /api/v1/searchbots/related_questions.
+type SearchbotRequest struct {
+	Question string `json:"question" binding:"required"`
+	SearchID string `json:"search_id,omitempty"`
+}
+
+// SearchbotHandler handles POST /api/v1/searchbots/related_questions.
+type SearchbotHandler struct {
+	searchSvc *service.SearchService
+	tenantSvc *service.TenantService
+	llm       searchbotLLM
+}
+
+// NewSearchbotHandler creates a new SearchbotHandler.
+func NewSearchbotHandler(searchSvc *service.SearchService, tenantSvc *service.TenantService, llm searchbotLLM) *SearchbotHandler {
+	return &SearchbotHandler{searchSvc: searchSvc, tenantSvc: tenantSvc, llm: llm}
+}
+
+// Handle generates related search questions based on a user query.
+// @Summary Generate Related Questions
+// @Description Generates 5-10 related search questions to expand the search scope.
+// @Tags searchbots
+// @Accept json
+// @Produce json
+// @Param request body SearchbotRequest true "Request body"
+// @Success 200 {object} map[string]interface{}
+// @Router /api/v1/searchbots/related_questions [post]
+func (h *SearchbotHandler) Handle(c *gin.Context) {
+	user, errorCode, errorMessage := GetUser(c)
+	if errorCode != common.CodeSuccess {
+		jsonError(c, errorCode, errorMessage)
+		return
+	}
+
+	var req SearchbotRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusOK, gin.H{
+			"code":    common.CodeArgumentError,
+			"data":    nil,
+			"message": "question is required",
+		})
+		return
+	}
+
+	if req.Question == "" {
+		c.JSON(http.StatusOK, gin.H{
+			"code":    common.CodeArgumentError,
+			"data":    nil,
+			"message": "question is required",
+		})
+		return
+	}
+
+	// Resolve model ID from search config if provided
+	modelID := ""
+	if req.SearchID != "" && h.searchSvc != nil {
+		if detail, err := h.searchSvc.GetDetail(req.SearchID); err == nil {
+			if sc, ok := detail["search_config"].(map[string]interface{}); ok {
+				if cid, ok := sc["chat_id"].(string); ok && cid != "" {
+					modelID = cid
+				}
+			}
+		}
+	}
+	if modelID == "" && h.tenantSvc != nil {
+		defaultModel, err := h.tenantSvc.GetDefaultModelName(user.ID, entity.ModelTypeChat)
+		if err == nil && defaultModel != "" {
+			modelID = defaultModel
+		}
+	}
+
+	messages := []modelModule.Message{
+		{Role: "system", Content: relatedQuestionPrompt},
+		{Role: "user", Content: "Keywords: " + req.Question + "\nRelated search terms:\n"},
+	}
+
+	genConf := &modelModule.ChatConfig{
+		Temperature: ptrFloat64(0.9),
+	}
+
+	response, err := h.llm.Chat(user.ID, modelID, messages, genConf)
+	if err != nil {
+		common.Warn("searchbot LLM call failed", zap.String("error", err.Error()))
+		c.JSON(http.StatusOK, gin.H{
+			"code":    common.CodeOperatingError,
+			"data":    nil,
+			"message": "LLM call failed",
+		})
+		return
+	}
+
+	var questions []string
+	if response != nil && response.Answer != nil {
+		questions = parseRelatedQuestions(*response.Answer)
+	}
+	c.JSON(http.StatusOK, gin.H{
+		"code":    common.CodeSuccess,
+		"data":    questions,
+		"message": "",
+	})
+}
+
+// ptrFloat64 returns a pointer to a float64 value.
+func ptrFloat64(v float64) *float64 { return &v }
+
+// parseRelatedQuestions extracts numbered list items from an LLM response.
+// Lines matching "^N. " are extracted and the number prefix is stripped.
+func parseRelatedQuestions(text string) []string {
+	lineRe := regexp.MustCompile(`^\d+\.\s`)
+	var result []string
+	for _, line := range strings.Split(text, "\n") {
+		if lineRe.MatchString(line) {
+			result = append(result, lineRe.ReplaceAllString(line, ""))
+		}
+	}
+	if result == nil {
+		return []string{}
+	}
+	return result
+}
+
+// relatedQuestionPrompt is the system prompt for generating related search questions.
+// Matches Python rag/prompts/related_question.md
+const relatedQuestionPrompt = `# Role
+You are an AI language model assistant tasked with generating **5-10 related questions** based on a user's original query.
+These questions should help **expand the search query scope** and **improve search relevance**.
+
+---
+
+## Instructions
+
+**Input:**
+You are provided with a **user's question**.
+
+**Output:**
+Generate **5-10 alternative questions** that are **related** to the original user question.
+These alternatives should help retrieve a **broader range of relevant documents** from a vector database.
+
+**Context:**
+Focus on **rephrasing** the original question in different ways, ensuring the alternative questions are **diverse but still connected** to the topic of the original query.
+Do **not** create overly obscure, irrelevant, or unrelated questions.
+
+**Fallback:**
+If you cannot generate any relevant alternatives, do **not** return any questions.
+
+---
+
+## Guidance
+
+1. Each alternative should be **unique** but still **relevant** to the original query.
+2. Keep the phrasing **clear, concise, and easy to understand**.
+3. Avoid overly technical jargon or specialized terms **unless directly relevant**.
+4. Ensure that each question **broadens** the search angle, **not narrows** it.
+
+---
+
+## Example
+
+**Original Question:**
+> What are the benefits of electric vehicles?
+
+**Alternative Questions:**
+1. How do electric vehicles impact the environment?
+2. What are the advantages of owning an electric car?
+3. What is the cost-effectiveness of electric vehicles?
+4. How do electric vehicles compare to traditional cars in terms of fuel efficiency?
+5. What are the environmental benefits of switching to electric cars?
+6. How do electric vehicles help reduce carbon emissions?
+7. Why are electric vehicles becoming more popular?
+8. What are the long-term savings of using electric vehicles?
+9. How do electric vehicles contribute to sustainability?
+10. What are the key benefits of electric vehicles for consumers?
+
+---
+
+## Reason
+Rephrasing the original query into multiple alternative questions helps the user explore **different aspects** of their search topic, improving the **quality of search results**.
+These questions guide the search engine to provide a **more comprehensive set** of relevant documents.`
--- a/internal/handler/searchbot_test.go
+++ b/internal/handler/searchbot_test.go
@@ -0,0 +1,227 @@
+//
+//  Copyright 2026 The InfiniFlow Authors. All Rights Reserved.
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+//
+
+package handler
+
+import (
+	"encoding/json"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/gin-gonic/gin"
+
+	"ragflow/internal/common"
+	"ragflow/internal/entity"
+	modelModule "ragflow/internal/entity/models"
+)
+
+// fakeSearchbotLLM implements searchbotLLM for testing.
+type fakeSearchbotLLM struct {
+	response string
+	err      error
+}
+
+func (f *fakeSearchbotLLM) Chat(tenantID, modelID string, messages []modelModule.Message, config *modelModule.ChatConfig) (*modelModule.ChatResponse, error) {
+	if f.err != nil {
+		return nil, f.err
+	}
+	return &modelModule.ChatResponse{Answer: &f.response}, nil
+}
+
+func setupSearchbotRequest(body string) (*gin.Context, *httptest.ResponseRecorder) {
+	gin.SetMode(gin.TestMode)
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Request = httptest.NewRequest("POST", "/api/v1/searchbots/related_questions",
+		strings.NewReader(body))
+	c.Request.Header.Set("Content-Type", "application/json")
+	c.Set("user", &entity.User{ID: "user-1"})
+	c.Set("user_id", "user-1")
+	return c, w
+}
+
+// TestSearchbotHandler_Success verifies the happy path.
+func TestSearchbotHandler_Success(t *testing.T) {
+	llm := &fakeSearchbotLLM{
+		response: `Here are some related questions:
+1. How do EV impact environment?
+2. What are advantages of EV?
+3. Cost of EV?`,
+	}
+	h := NewSearchbotHandler(nil, nil, llm)
+
+	c, w := setupSearchbotRequest(`{"question": "EV benefits"}`)
+	h.Handle(c)
+
+	var resp map[string]interface{}
+	json.Unmarshal(w.Body.Bytes(), &resp)
+	if resp["code"] != float64(common.CodeSuccess) {
+		t.Fatalf("expected code 0, got %v: %v", resp["code"], resp["message"])
+	}
+
+	questions, ok := resp["data"].([]interface{})
+	if !ok {
+		t.Fatalf("expected data array, got %T", resp["data"])
+	}
+	if len(questions) != 3 {
+		t.Fatalf("expected 3 questions, got %d", len(questions))
+	}
+	if questions[0] != "How do EV impact environment?" {
+		t.Errorf("unexpected [0]: %v", questions[0])
+	}
+}
+
+// TestSearchbotHandler_EmptyResponse verifies empty LLM response returns empty list.
+func TestSearchbotHandler_EmptyResponse(t *testing.T) {
+	llm := &fakeSearchbotLLM{
+		response: "No related questions found.",
+	}
+	h := NewSearchbotHandler(nil, nil, llm)
+
+	c, w := setupSearchbotRequest(`{"question": "EV benefits"}`)
+	h.Handle(c)
+
+	var resp map[string]interface{}
+	json.Unmarshal(w.Body.Bytes(), &resp)
+	if resp["code"] != float64(common.CodeSuccess) {
+		t.Fatalf("expected code 0, got %v: %v", resp["code"], resp["message"])
+	}
+	questions, ok := resp["data"].([]interface{})
+	if !ok {
+		t.Fatalf("expected data array, got %T", resp["data"])
+	}
+	if len(questions) != 0 {
+		t.Errorf("expected 0 questions, got %d", len(questions))
+	}
+}
+
+// TestSearchbotHandler_LLMFailure verifies error handling on LLM failure.
+func TestSearchbotHandler_LLMFailure(t *testing.T) {
+	llm := &fakeSearchbotLLM{
+		err: errFake{msg: "LLM unavailable"},
+	}
+	h := NewSearchbotHandler(nil, nil, llm)
+
+	c, w := setupSearchbotRequest(`{"question": "EV benefits"}`)
+	h.Handle(c)
+
+	var resp map[string]interface{}
+	json.Unmarshal(w.Body.Bytes(), &resp)
+	code, _ := resp["code"].(float64)
+	if code == 0 {
+		t.Errorf("expected error code, got 0")
+	}
+}
+
+// TestSearchbotHandler_MissingQuestion verifies validation.
+func TestSearchbotHandler_MissingQuestion(t *testing.T) {
+	llm := &fakeSearchbotLLM{response: "dummy"}
+	h := NewSearchbotHandler(nil, nil, llm)
+
+	c, w := setupSearchbotRequest(`{}`)
+	h.Handle(c)
+
+	var resp map[string]interface{}
+	json.Unmarshal(w.Body.Bytes(), &resp)
+	code, _ := resp["code"].(float64)
+	if code == 0 {
+		t.Errorf("expected error code, got 0")
+	}
+}
+
+// errFake implements error for testing.
+type errFake struct{ msg string }
+
+func (e errFake) Error() string { return e.msg }
+
+// Existing parse tests below
+func TestParseRelatedQuestions_Standard(t *testing.T) {
+	input := `1. How do electric vehicles impact the environment?
+2. What are the advantages of owning an electric car?
+3. What is the cost-effectiveness?`
+
+	got := parseRelatedQuestions(input)
+	if len(got) != 3 {
+		t.Fatalf("expected 3, got %d", len(got))
+	}
+	if got[0] != "How do electric vehicles impact the environment?" {
+		t.Errorf("unexpected [0]: %q", got[0])
+	}
+	if got[1] != "What are the advantages of owning an electric car?" {
+		t.Errorf("unexpected [1]: %q", got[1])
+	}
+	if got[2] != "What is the cost-effectiveness?" {
+		t.Errorf("unexpected [2]: %q", got[2])
+	}
+}
+
+func TestParseRelatedQuestions_Empty(t *testing.T) {
+	got := parseRelatedQuestions("")
+	if len(got) != 0 {
+		t.Errorf("expected 0, got %d", len(got))
+	}
+}
+
+func TestParseRelatedQuestions_NoNumberedLines(t *testing.T) {
+	input := `Here are some related questions:
+- First question
+- Second question`
+
+	got := parseRelatedQuestions(input)
+	if len(got) != 0 {
+		t.Errorf("expected 0, got %d", len(got))
+	}
+}
+
+func TestParseRelatedQuestions_MixedContent(t *testing.T) {
+	input := `Here are some related questions:
+1. First related question.
+Some explanation text.
+2. Second related question.
+More text.
+3. Third related question.`
+
+	got := parseRelatedQuestions(input)
+	if len(got) != 3 {
+		t.Fatalf("expected 3, got %d", len(got))
+	}
+	if got[0] != "First related question." {
+		t.Errorf("unexpected [0]: %q", got[0])
+	}
+	if got[1] != "Second related question." {
+		t.Errorf("unexpected [1]: %q", got[1])
+	}
+	if got[2] != "Third related question." {
+		t.Errorf("unexpected [2]: %q", got[2])
+	}
+}
+
+func TestParseRelatedQuestions_MultiDigit(t *testing.T) {
+	input := `10. Tenth question.
+11. Eleventh question.`
+
+	got := parseRelatedQuestions(input)
+	if len(got) != 2 {
+		t.Fatalf("expected 2, got %d", len(got))
+	}
+	if got[0] != "Tenth question." {
+		t.Errorf("unexpected [0]: %q", got[0])
+	}
+	if got[1] != "Eleventh question." {
+		t.Errorf("unexpected [1]: %q", got[1])
+	}
+}
--- a/internal/router/router.go
+++ b/internal/router/router.go
@@ -40,8 +40,9 @@ type Router struct {
 	memoryHandler        *handler.MemoryHandler
 	mcpHandler           *handler.MCPHandler
 	skillSearchHandler   *handler.SkillSearchHandler
-	providerHandler      *handler.ProviderHandler
-	agentHandler         *handler.AgentHandler
+	providerHandler           *handler.ProviderHandler
+	agentHandler              *handler.AgentHandler
+	relatedQuestionsHandler   *handler.SearchbotHandler
 }

 // NewRouter create router
@@ -65,6 +66,7 @@ func NewRouter(
 	skillSearchHandler *handler.SkillSearchHandler,
 	providerHandler *handler.ProviderHandler,
 	agentHandler *handler.AgentHandler,
+	relatedQuestionsHandler *handler.SearchbotHandler,
 ) *Router {
 	return &Router{
 		authHandler:          authHandler,
@@ -86,6 +88,7 @@ func NewRouter(
 		skillSearchHandler:   skillSearchHandler,
 		providerHandler:      providerHandler,
 		agentHandler:         agentHandler,
+		relatedQuestionsHandler: relatedQuestionsHandler,
 	}
 }

@@ -214,6 +217,9 @@ func (r *Router) Setup(engine *gin.Engine) {
 				chats.GET("/:chat_id/sessions", r.chatSessionHandler.ListChatSessions)
 			}

+			// Searchbot routes
+			v1.POST("/searchbots/related_questions", r.relatedQuestionsHandler.Handle)
+
 			// Dataset routes
 			datasets := v1.Group("/datasets")
 			{