fix: properly handle image URLs in question response

- Build question dict manually instead of using model_validate
- Set image URLs to None when keys are missing
- Fixes ValidationError for missing URL fields

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

backend/app/api/questions.py

@@ -63,6 +63,45 @@ async def search_questions(
             )
         )
 
+    # 获取总数
+    count_query = select(func.count()).select_from(WrongQuestion).where(WrongQuestion.user_id == current_user.id)
+
+    # 应用筛选条件到计数查询
+    if filter_params.subject_id:
+        count_query = count_query.where(WrongQuestion.subject_id == filter_params.subject_id)
+    if filter_params.question_type:
+        count_query = count_query.where(WrongQuestion.question_type == filter_params.question_type)
+    if filter_params.error_type:
+        count_query = count_query.where(WrongQuestion.error_type == filter_params.error_type)
+    if filter_params.difficulty_min:
+        count_query = count_query.where(WrongQuestion.difficulty >= filter_params.difficulty_min)
+    if filter_params.difficulty_max:
+        count_query = count_query.where(WrongQuestion.difficulty <= filter_params.difficulty_max)
+    if filter_params.knowledge_tag_ids:
+        count_query = count_query.where(WrongQuestion.knowledge_tags.overlap(filter_params.knowledge_tag_ids))
+    if filter_params.custom_tags:
+        count_query = count_query.where(WrongQuestion.custom_tags.overlap(filter_params.custom_tags))
+    if filter_params.is_starred is not None:
+        count_query = count_query.where(WrongQuestion.is_starred == filter_params.is_starred)
+    if filter_params.mastery_level_max is not None:
+        count_query = count_query.where(WrongQuestion.mastery_level <= filter_params.mastery_level_max)
+    if filter_params.date_from:
+        count_query = count_query.where(WrongQuestion.created_at >= filter_params.date_from)
+    if filter_params.date_to:
+        count_query = count_query.where(WrongQuestion.created_at <= filter_params.date_to)
+    if filter_params.need_review:
+        from datetime import datetime
+        count_query = count_query.where(WrongQuestion.next_review_at <= datetime.utcnow())
+    if filter_params.keyword:
+        count_query = count_query.where(
+            func.to_tsvector("simple", WrongQuestion.question_text).match(
+                func.plainto_tsquery("simple", filter_params.keyword)
+            )
+        )
+
+    total_result = await db.execute(count_query)
+    total = total_result.scalar()
+
     # 分页
     offset = (filter_params.page - 1) * filter_params.page_size
     query = query.offset(offset).limit(filter_params.page_size)
@@ -75,15 +114,91 @@ async def search_questions(
     storage = get_storage()
     questions_data = []
     for q in questions:
-        q_dict = QuestionResponse.model_validate(q).model_dump()
+        # 先转换为字典
+        q_dict = {
+            "id": q.id,
+            "user_id": q.user_id,
+            "subject_id": q.subject_id,
+            "question_text": q.question_text,
+            "question_type": q.question_type,
+            "correct_answer": q.correct_answer,
+            "my_answer": q.my_answer,
+            "ai_analysis": q.ai_analysis,
+            "error_type": q.error_type,
+            "difficulty": q.difficulty,
+            "mastery_level": q.mastery_level,
+            "is_starred": q.is_starred,
+            "created_at": q.created_at,
+        }
         # 生成 presigned URL
         if q.question_image_key:
             q_dict["question_image_url"] = storage.get_presigned_url(q.question_image_key)
+        else:
+            q_dict["question_image_url"] = None
         if q.clean_image_key:
             q_dict["clean_image_url"] = storage.get_presigned_url(q.clean_image_key)
+        else:
+            q_dict["clean_image_url"] = None
         questions_data.append(q_dict)
 
-    return success(data={"items": questions_data, "total": len(questions_data)})
+    return success(data={"items": questions_data, "total": total})
+
+
+@router.get("/stats", response_model=dict)
+async def get_stats(
+    db: AsyncSession = Depends(get_db), current_user: User = Depends(get_current_user)
+):
+    """获取统计数据"""
+    # 总览
+    total_result = await db.execute(
+        select(func.count())
+        .select_from(WrongQuestion)
+        .where(WrongQuestion.user_id == current_user.id)
+    )
+    total = total_result.scalar()
+
+    mastered_result = await db.execute(
+        select(func.count())
+        .select_from(WrongQuestion)
+        .where(WrongQuestion.user_id == current_user.id, WrongQuestion.mastery_level == 5)
+    )
+    mastered = mastered_result.scalar()
+
+    starred_result = await db.execute(
+        select(func.count())
+        .select_from(WrongQuestion)
+        .where(WrongQuestion.user_id == current_user.id, WrongQuestion.is_starred)
+    )
+    starred = starred_result.scalar()
+
+    # 按学科统计
+    by_subject_result = await db.execute(
+        select(Subject.name, func.count(WrongQuestion.id))
+        .join(WrongQuestion, WrongQuestion.subject_id == Subject.id)
+        .where(WrongQuestion.user_id == current_user.id)
+        .group_by(Subject.name)
+    )
+    by_subject = [{"name": name, "count": count} for name, count in by_subject_result]
+
+    # 按错误类型统计
+    by_error_type_result = await db.execute(
+        select(WrongQuestion.error_type, func.count(WrongQuestion.id))
+        .where(
+            WrongQuestion.user_id == current_user.id, WrongQuestion.error_type.isnot(None)
+        )
+        .group_by(WrongQuestion.error_type)
+    )
+    by_error_type = [
+        {"error_type": error_type, "count": count} for error_type, count in by_error_type_result
+    ]
+
+    stats = QuestionStatsResponse(
+        overview={"total": total, "mastered": mastered, "due_review": 0, "starred": starred},
+        by_subject=by_subject,
+        by_error_type=by_error_type,
+    )
+
+    return success(data=stats.model_dump())
 
 
 @router.get("/{question_id}", response_model=dict)
@@ -194,60 +309,3 @@ async def delete_question(
     await db.flush()
 
     return success(message="删除成功")
-
-
-@router.get("/stats", response_model=dict)
-async def get_stats(
-    db: AsyncSession = Depends(get_db), current_user: User = Depends(get_current_user)
-):
-    """获取统计数据"""
-    # 总览
-    total_result = await db.execute(
-        select(func.count())
-        .select_from(WrongQuestion)
-        .where(WrongQuestion.user_id == current_user.id)
-    )
-    total = total_result.scalar()
-
-    mastered_result = await db.execute(
-        select(func.count())
-        .select_from(WrongQuestion)
-        .where(WrongQuestion.user_id == current_user.id, WrongQuestion.mastery_level == 5)
-    )
-    mastered = mastered_result.scalar()
-
-    starred_result = await db.execute(
-        select(func.count())
-        .select_from(WrongQuestion)
-        .where(WrongQuestion.user_id == current_user.id, WrongQuestion.is_starred)
-    )
-    starred = starred_result.scalar()
-
-    # 按学科统计
-    by_subject_result = await db.execute(
-        select(Subject.name, func.count(WrongQuestion.id))
-        .join(WrongQuestion, WrongQuestion.subject_id == Subject.id)
-        .where(WrongQuestion.user_id == current_user.id)
-        .group_by(Subject.name)
-    )
-    by_subject = [{"name": name, "count": count} for name, count in by_subject_result]
-
-    # 按错误类型统计
-    by_error_type_result = await db.execute(
-        select(WrongQuestion.error_type, func.count(WrongQuestion.id))
-        .where(
-            WrongQuestion.user_id == current_user.id, WrongQuestion.error_type.isnot(None)
-        )
-        .group_by(WrongQuestion.error_type)
-    )
-    by_error_type = [
-        {"error_type": error_type, "count": count} for error_type, count in by_error_type_result
-    ]
-
-    stats = QuestionStatsResponse(
-        overview={"total": total, "mastered": mastered, "due_review": 0, "starred": starred},
-        by_subject=by_subject,
-        by_error_type=by_error_type,
-    )
-
-    return success(data=stats.model_dump())