python-web开发

3、fastApi-特殊的请求类型

2023-07-29  本文已影响0人  许忠慧

一、Cookie 参数

from typing import Annotated, Union
from fastapi import Cookie, FastAPI

app = FastAPI()

# 传递 cookie 参数
@app.get("/")
def root(ads_id: Annotated[Union[str, None], Cookie()] = None):
    return {"ads_id": ads_id}

二、 Header参数

from typing import Annotated, Union
from fastapi import FastAPI, Header

app = FastAPI()


# 传递 header 参数
@app.get("/")
def root(ads_id: Annotated[Union[str, None], Header()] = None):
    return {"ads_id": ads_id}

三、接收表单数据请求

基础语法:

from fastapi import FastAPI, Form

app = FastAPI()


@app.post("/login/")
def login(username: str = Form(), password: str = Form()):
    return True

四、请求文件

1、基础语法:

from fastapi import FastAPI, File, UploadFile

app = FastAPI()


# 适用于小型二进制文件或数据, 会将文件存储到内存
@app.post("/files/")
def create_file(file: bytes = File()):
    return {"file_size": len(file)}


# 适用于大型文件, 存储在内存的文件超出最大上限时,FastAPI 会把文件存入磁盘
@app.post("/uploadfile/")
def create_upload_file(file: UploadFile):
    return {"filename": file.filename}

UploadFile属性:

  • filename::文件名
    -content_type:文件格式(MIME 类型 / 媒体类型)字符串(str),例如,image/jpeg
  • file:文件对象

UploadFile文件支持的async方法:

  • write(data)
  • read(size)
  • seek(offset)
    • 例如,await myfile.seek(0) 移动到文件开头
    • 执行 await myfile.read()后,需再次读取已读取内容时,这种方法特别好用
  • close()

因为上述方法都是async 方法,要搭配await使用,例如:在async 方法内,要以如下方式读取文件:
contents = await myfile.read()

在普通def 路径操作函数 内,则可以直接访问 UploadFile.file

2、可选文件上传

写法:

from fastapi import FastAPI, File, UploadFile

app = FastAPI()


@app.post("/files/")
async def create_file(file: bytes | None = File(default=None)):
    if not file:
        return {"message": "No file sent"}
    else:
        return {"file_size": len(file)}


@app.post("/uploadfile/")
async def create_upload_file(file: UploadFile | None = None):
    if not file:
        return {"message": "No upload file sent"}
    else:
        return {"filename": file.filename}

3、多文件上传

语法:

from fastapi import FastAPI, File, UploadFile
from fastapi.responses import HTMLResponse

app = FastAPI()


@app.post("/files/")
async def create_files(files: list[bytes] = File()):
    return {"file_sizes": [len(file) for file in files]}


@app.post("/uploadfiles/")
async def create_upload_files(files: list[UploadFile]):
    return {"filenames": [file.filename for file in files]}


@app.get("/")
async def main():
    content = """
<body>
<form action="/files/" enctype="multipart/form-data" method="post">
<input name="files" type="file" multiple>
<input type="submit">
</form>
<form action="/uploadfiles/" enctype="multipart/form-data" method="post">
<input name="files" type="file" multiple>
<input type="submit">
</form>
</body>
    """
    return HTMLResponse(content=content)

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