Question

我已经使用HTTP触发器在Azure上创建了Cloud Function，并且希望能够使用表单处理文件上传。
我的入口点看起来像这样：

def main(req: func.HttpRequest) -> func.HttpResponse:
    body = req.get_body()
    headers=req.headers
    ...

问题是我在body中得到的是原始二进制文件，我不知道如何解码它并获取上载的文件。

有人知道实现这一目标的好方法吗？

Answer 1

我想说，这是一种Azure本机方法，而Python本机。

天蓝色本原方法

azure.functions.HttpRequest具有一个files生成器的MultiDict属性。使用方法如下：

import logging

import azure.functions as func


def main(req: func.HttpRequest) -> func.HttpResponse:
    for input_file in req.files.values():
        filename = input_file.filename
        contents = input_file.stream.read()

        logging.info('Filename: %s' % filename)
        logging.info('Contents:')
        logging.info(contents)

        [..process the file here as you want..]

    return func.HttpResponse(f'Done\n')

Python原生方法

如果您只想使用标准的Python库（例如，为了提高可移植性），那么您应该知道您需要在体内解析的是二进制形式的MIME multipart message：

Content-Type: multipart/form-data; boundary=--------------------------1715cbf149d89cd9

--------------------------1715cbf149d89cd9
Content-Disposition: form-data; name="data"; filename="test.txt"
Content-Type: application/octet-stream

this is a test document

--------------------------1715cbf149d89cd9--

要复制的示例脚本：

echo 'this is a test document' > test.txt && curl -F 'data=@test.txt' 'https://[..yourfunctionname..].azurewebsites.net/api/HttpTrigger'

您会感到惊讶，但是email模块would do it为您服务（我个人认为它的名字不好用）。

下面的示例代码（注意：没有错误处理！）突出了核心思想：

import cgi
import email
import logging

import azure.functions as func


def main(req: func.HttpRequest) -> func.HttpResponse:
    # Content-Type should be 'multipart/form-data' with some boundary
    content_type = req.headers.get('Content-Type')
    body = req.get_body().decode('utf-8')

    mime_template = 'MIME-Version: 1.0\nContent-Type: %s\n%s'
    post_data = email.parser.Parser().parsestr(mime_template % (content_type, body))

    # Content-Disposition header format:
    #  'form-data; name="data"; filename="test.txt"'
    disposition = post_data.get_payload()[0]['Content-Disposition']
    disposition_value = cgi.parse_header('Content-Disposition: %s' % disposition)[1]

    filename = disposition_value['filename']
    contents = post_data.get_payload()[0].get_payload()

    logging.info('Filename: %s' % filename)
    logging.info('Contents:')
    logging.info(contents)

    [..process the file here as you want..]

    return func.HttpResponse(f'Done\n')

Answer 2

我认为最好的解决方法是将这些二进制数据转换为文件，然后上传到blob存储，

        #upload to picture to blob storage
        block_blob_service = BlockBlobService(account_name=accuntName, account_key=accuntKey)
        container_name = 'machineimages'
        blob_name = image_name + '.jpeg'
        # Creating the blob
        block_blob_service.create_blob_from_bytes(container_name, blob_name, decoded_image,
        content_settings=ContentSettings(content_type='image/png'))
        logging.info("Successfull blob creating ")

        # Returning a succesful post request 
        return func.HttpResponse(f"successful request")

这里是 sample 。

Answer 3

显然，我们默认获取的最新python SDK [1]中既没有 create_blob_from_bytes 也没有 BlobServiceClient 。

所以我不得不绕道而行。

    from azure.storage.blob import (
        BlobServiceClient,
        ContentSettings
    )
    # decoding base64 image from json body
    decoded_image = base64.b64decode(image)
    blob_service_client = BlobServiceClient.from_connection_string(
        conn_str=storage_connection_string
        )
    logging.debug(f'getting client for container : {container_name}')
    container_client = 
    blob_service_client.get_container_client(container=container_name)
    blob_client = container_client.get_blob_client(blob_name)
    if blob_client.exists():
        blob_client.delete_blob()
    blob_client = blob_service_client.get_blob_client(container=container_name, 
    blob=blob_name)
    try:
        blob_client.upload_blob(decoded_image)
        content_settings =ContentSettings(content_type='image/png')
        logging.debug(f'setting the content type : {content_settings}')
    except Exception as e:
        logging.error(str(e))

[1] https://docs.microsoft.com/en-us/python/api/azure-storage-blob/azure.storage.blob.blobserviceclient?view=azure-python

使用Python上传Azure云功能HTTP文件

3 个答案:

天蓝色本原方法

Python原生方法