feature: 新增小说封面图片生成功能

backend/app/api/project_covers.py

@@ -0,0 +1,66 @@
+"""项目封面生成与下载 API"""
+from __future__ import annotations
+
+from pydantic import BaseModel, Field
+from fastapi import APIRouter, Depends, HTTPException, Request
+from fastapi.responses import FileResponse
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.database import get_db
+from app.services.cover_generation_service import cover_generation_service
+
+router = APIRouter(prefix="/projects", tags=["项目封面"])
+
+
+class CoverGenerateRequest(BaseModel):
+    overwrite: bool = Field(default=True, description="是否覆盖已有封面")
+
+
+class CoverGenerateResponse(BaseModel):
+    project_id: str
+    cover_status: str
+    cover_image_url: str | None = None
+    cover_prompt: str | None = None
+    provider: str | None = None
+    model: str | None = None
+    message: str
+
+
+@router.post("/{project_id}/cover/generate", response_model=CoverGenerateResponse, summary="生成项目封面")
+async def generate_project_cover(
+    project_id: str,
+    payload: CoverGenerateRequest,
+    request: Request,
+    db: AsyncSession = Depends(get_db),
+):
+    user_id = getattr(request.state, "user_id", None)
+    if not user_id:
+        raise HTTPException(status_code=401, detail="未登录")
+
+    result = await cover_generation_service.generate_cover(
+        db=db,
+        user_id=user_id,
+        project_id=project_id,
+        overwrite=payload.overwrite,
+    )
+    return CoverGenerateResponse(**result)
+
+
+@router.get("/{project_id}/cover/download", summary="下载项目封面")
+async def download_project_cover(
+    project_id: str,
+    request: Request,
+    db: AsyncSession = Depends(get_db),
+):
+    user_id = getattr(request.state, "user_id", None)
+    if not user_id:
+        raise HTTPException(status_code=401, detail="未登录")
+
+    project, file_path = await cover_generation_service.get_cover_download_path(
+        db=db,
+        user_id=user_id,
+        project_id=project_id,
+    )
+    suffix = file_path.suffix or ".png"
+    filename = f"{project.title}-cover{suffix}"
+    return FileResponse(path=file_path, filename=filename, media_type="application/octet-stream")

backend/app/api/settings.py

@@ -14,6 +14,7 @@ import time
 
 from app.database import get_db
 from app.models.settings import Settings
+from app.services.cover_generation_service import cover_generation_service
 from app.schemas.settings import (
     SettingsCreate, SettingsUpdate, SettingsResponse,
     APIKeyPreset, APIKeyPresetConfig, PresetCreateRequest,
@@ -29,6 +30,13 @@ logger = get_logger(__name__)
 router = APIRouter(prefix="/settings", tags=["设置管理"])
 
 
+class CoverSettingsTestRequest(BaseModel):
+    cover_api_provider: str
+    cover_api_key: str
+    cover_api_base_url: Optional[str] = None
+    cover_image_model: str
+
+
 def read_env_defaults() -> Dict[str, Any]:
     """从.env文件读取默认配置（仅读取，不修改）"""
     return {
@@ -142,6 +150,25 @@ async def get_settings(
     return settings
 
 
+@router.post("/cover/test")
+async def test_cover_settings(
+    data: CoverSettingsTestRequest,
+    user: User = Depends(require_login),
+):
+    result = await cover_generation_service.test_cover_settings(
+        provider=data.cover_api_provider,
+        api_key=data.cover_api_key,
+        api_base_url=data.cover_api_base_url,
+        model=data.cover_image_model,
+    )
+    return {
+        "success": result.success,
+        "message": result.message,
+        "provider": result.provider,
+        "model": result.model,
+    }
+
+
 @router.post("", response_model=SettingsResponse)
 async def save_settings(
     data: SettingsCreate,