[Python] 上次聊前后端分工还是有点空洞， 这次来贴一个 demo

https://www.v2ex.com/t/1055357?p=1#reply32 上期回顾

项目地址：

https://github.com/allmonday/pydantic-resolve-demo

主要介绍如何借助 graphql resolver 和 dataloader 这两个工具

将 graphql 中对数据组合的便利性带到 fastapi/ django ninja (支持 pydantic ）项目中来。

• 通过继承来复用查询接口
• 通过 dataloader 来扩展需要的字段
• 通过 openapi.json 把方法和 schema 暴露到前端快速使用。

class MyBlogSite(BaseModel):
    name: str
    # blogs: list[Blog] = []  # this will not include comments and comment_count
    blogs: list[MyBlog] = []
    async def resolve_blogs(self):
        return await get_blogs()

    comment_count: int = 0
    def post_comment_count(self):
        return sum([b.comment_count for b in self.blogs])
        
class MyBlog(Blog):
    # comments: list[Comment] = []  # this will not include user field
    comments: list[MyComment] = []
    def resolve_comments(self, loader=LoaderDepend(blog_to_comments_loader)):
        return loader.load(self.id)

    comment_count: int = 0
    def post_comment_count(self):
        return len(self.comments)

class MyComment(Comment):
    user: Optional[User] = None
    def resolve_user(self, loader=LoaderDepend(user_loader)):
        return loader.load(self.user_id)