FastAPI从入门到实战（14）——JSON编码兼容与更新请求

Love The Way You Lie 2024-03-31 14:45 77阅读 0赞

> 针对数据格式和类型问题，fastapi内置了一个很好的转换器，本文就相关内容主要记录编码和请求更新相关内容；

### json兼容编码器 ###

class Animal(BaseModel):
        name: str = "JACK"
        age: int = 21
        birthday: datetime = datetime.now()
    
    
    @app08.put("/stu08/json_update/")
    def stu07_update(animal: Animal):
        print("animal__type:", type(animal), "animal:", animal)
        json_data = jsonable_encoder(animal)
        print("animal__type:", type(json_data), "animal:", json_data)
        return animal
    
    # 输出结果
    # animal__type: <class 'stu.stu07.Animal'> animal: name='JACK' age=21 birthday=datetime.datetime(2022, 12, 2, 18, 31, 38, 373484)
    # animal__type: <class 'dict'> animal: {'name': 'JACK', 'age': 21, 'birthday': '2022-12-02T18:31:38.373484'}

> 现在我们的请求大多都是`Pydantic`模型类的，在实际的应用中并不会兼容，例如存储到数据库中，利用fastapi内置的`jsonable_encoder()`函数就能很好的解决相关的问题；会进行类型的转换，例如`pydantic转dict`，`datetime转str`…

![image-20221202183156868][]

### PUT请求更新数据 ###

class City(BaseModel):
        province: Optional[str] = Field("重庆")
        cityname: Optional[str] = Field("重庆")
        gdp: Optional[float] = Field(236542.25)
        towns: Optional[List[str]] = Field(["奉节","云阳","万州"])
        population: Optional[int] = Field(562312)
    
    
    cityitem = {
        
        1: {
        
            "province": "四川",
            "cityname": "成都",
            "gdp": 12653.56,
        },
        2: {
        
            "province": "山西",
            "cityname": "太原",
            "gdp": 10003.56,
            "towns": ["清徐", "小店", "迎泽"],
            "population": 556565
        },
        3: {
        
            "province": "吉林",
            "cityname": "长春",
            "gdp": 10253.85,
            "towns": [],
            "population": 54160
        }
    }
    
    
    @app08.put("/stu08/cityput/{cityid}")
    async def stu08_city_put(
            city: City = Body(default={
        
            "province": "湖南",
            "cityname": "长沙",
            "gdp": 15553.85,
            "towns": ["安化"],
            "population": 236160
        }),
            cityid: int = Path(ge=1, le=3),
    ):
        update_city = jsonable_encoder(city)
        cityitem[cityid] = update_city
        print(cityitem)
        return update_city

> `PUT`更新数据很简单，接受一个同类型的请求体，将接收的请求体进行解码，就是进行对应的类型转换（基于上面的JSON编码器），然后进行数据存储：

![image-20221203170414554][]

![image-20221203170443104][]

### PATCH请求更新数据 ###

@app08.patch("/stu08/citypatch/{cityid}")
    async def stu08_city_patch(
            city: City,
            cityid: int = Path(ge=1, le=3),
    ):
        city_item_data = cityitem[cityid] # 获取cityitem内对应id的数据
        city_item_model = City(**city_item_data) # 将获取到的数据转为City类型
        city_item_update = city.dict(exclude_unset=True) # 将获取的数据设置为不包含默认值的字典
        city_item_update_result = city_item_model.copy(update=city_item_update) # 使用pydantic方法进行数据更新
        cityitem[cityid] = jsonable_encoder(city_item_update_result) # 将更新后的数据进行编码并放回cityitem
        print(cityitem)
        return city_item_update_result

> 这个就是部分更新，了解方法即可，实际应用中，还是PUT方法用的多，具体过程参看上面代码的注释；

![image-20221203170647405][]

![image-20221203170709665][]

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感谢阅读！

九陌斋地址：[https://blog.jiumoz.com/archives/fastapi-cong-ru-men-dao-shi-zhan-14json-bian-ma-jian-rong-yu-geng-xin-qing-qiu][https_blog.jiumoz.com_archives_fastapi-cong-ru-men-dao-shi-zhan-14json-bian-ma-jian-rong-yu-geng-xin-qing-qiu]

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[image-20221202183156868]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/8387468c16834883a889da04e9eeaa8c.png
[image-20221203170414554]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/81f37723138d459bafc1c5be330d0009.png
[image-20221203170443104]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/c2887fb6d7314175b2b7d50f0b573e4b.png
[image-20221203170647405]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/43a9dac3f32c431ca61e62f0fe1a22ef.png
[image-20221203170709665]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/53d66890493e4a319654ece2eacddb0a.png
[https_blog.jiumoz.com_archives_fastapi-cong-ru-men-dao-shi-zhan-14json-bian-ma-jian-rong-yu-geng-xin-qing-qiu]: https://blog.jiumoz.com/archives/fastapi-cong-ru-men-dao-shi-zhan-14json-bian-ma-jian-rong-yu-geng-xin-qing-qiu
[30b7b3ba49344b6691969078c7df196e.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/c8fed86f32a04ed9bb361e9fb9139e8a.png