Body - Multiple Parameters

Mix Path, Query and body parameters

我们可以自由的混合 Path 和 Query 和 request body，FastAPI 知道如何自动处理

request body 参数也是可选的

from fastapi import FastAPI, Path
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str = None
    price: float
    tax: float = None


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int = Path(..., title="The ID of the item to get", ge=0, le=1000),
    q: str = None,
    item: Item = None,
):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})
    if item:
        results.update({"item": item})
    return results

注：再上面的例子中，request body 是可选的

Multiple body parameters

可以同时声明多个 request body，如下面的例子同时声明了 Item 和 User

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str = None
    price: float
    tax: float = None


class User(BaseModel):
    username: str
    full_name: str = None


@app.put("/items/{item_id}")
async def update_item(*, item_id: int, item: Item, user: User):
    results = {"item_id": item_id, "item": item, "user": user}
    return results

注：上述例子中期望的 body 会加上参数名作为字段名称，即

{
    "item": {
        "name": "Foo",
        "description": "The pretender",
        "price": 42.0,
        "tax": 3.2
    },
    "user": {
        "username": "dave",
        "full_name": "Dave Grohl"
    }
}

FastAPI 将会对接收到的 body 进行自动转换和数据验证，因此 item 将会自动被转换为 Item 类型

Singular values in body

对于查询参数和路径参数而言，可以用 Query 和 Path 声明额外的数据。FastAPI 为 request body 提供了 Body 函数

例如，在上面的例子中，想要声明另一个单值键 importance，如果直接在参数中声明，会由于是单值而被 FastAPI 识别为查询参数，这时可以使用 Body 来告诉 FastAPI 要声名的是 Body

from fastapi import Body, FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str = None
    price: float
    tax: float = None


class User(BaseModel):
    username: str
    full_name: str = None


@app.put("/items/{item_id}")
async def update_item(
    *, item_id: int, item: Item, user: User, importance: int = Body(...)
):
    results = {"item_id": item_id, "item": item, "user": user, "importance": importance}
    return results

按照上述声明，则结果为

{
    "item": {
        "name": "Foo",
        "description": "The pretender",
        "price": 42.0,
        "tax": 3.2
    },
    "user": {
        "username": "dave",
        "full_name": "Dave Grohl"
    },
    "importance": 5
}

Multiple body params and query

单值变量将会被解释为查询参数，而不需要用 Query 显式声明，例如

from fastapi import Body, FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str = None
    price: float
    tax: float = None


class User(BaseModel):
    username: str
    full_name: str = None


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,
    item: Item,
    user: User,
    importance: int = Body(..., gt=0),
    q: str = None
):
    results = {"item_id": item_id, "item": item, "user": user, "importance": importance}
    if q:
        results.update({"q": q})
    return results

中 q 为查询参数

注：Body 和 Query ，Path 一样有所有的验证参数和元信息

Embed a single body parameter

为 Body 添加 embed 参数可以使得单个 body 也是嵌入的，例如

from fastapi import Body, FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str = None
    price: float
    tax: float = None


@app.put("/items/{item_id}")
async def update_item(*, item_id: int, item: Item = Body(..., embed=True)):
    results = {"item_id": item_id, "item": item}
    return results

期望的 body 是

{
    "item": {
        "name": "Foo",
        "description": "The pretender",
        "price": 42.0,
        "tax": 3.2
    }
}