无法直接将BytesIO文件上传至Azure Blob，需先保存至本地硬盘

用requests从数据服务器获取文件后，直接把BytesIO对象上传到Azure Blob会生成空文件，但先保存到本地硬盘再读取上传就能正常工作。

直接上传（生成空文件）的代码 #

import BytesIO
from azure.storage.blob import BlobServiceClient

v_file = BytesIO()
for chunk in r.iter_content(chunk_size=1024 * 1024):
    if chunk:
        v_file.write(chunk)

container_name = 'test'
blob_name = 'test_blob'
blob_service_client = BlobServiceClient.from_connection_string(connection_string)
blob_client = blob_service_client.get_blob_client(container=container_name, blob=blob_name)
blob_client.upload_blob(data=v_file, overwrite=True)

本地保存后上传（正常工作）的代码 #

download_folder = 'C:/downloaders'
fqfilename = download_folder + "\\" + filename
with BytesIO() as v_file:
    for chunk in r.iter_content(chunk_size=1024 * 1024):
        if chunk:
            counter += len(chunk)
            size = counter / (1024)
            v_file.write(chunk)
            with open(fqfilename, 'wb') as f:
                f.write(v_file.getbuffer())

with open (fqfilename, 'rb') as file_to_blob:
    print(f' {file_to_blob} uploaded to the blob for date {date}')
    container_name = 'test'
    blob_name = 'test_blob'
    blob_service_client = BlobServiceClient.from_connection_string(connection_string)
    blob_client = blob_service_client.get_blob_client(container=container_name, blob=blob_name)
    blob_client.upload_blob(data=v_file, overwrite=True)
    f.close()

问题核心是BytesIO对象的文件指针位置：写完所有数据后，指针停留在文件末尾，upload_blob从当前指针位置开始读取，自然读不到内容。

只需在上传前添加一行代码，把指针重置到文件开头：

v_file.seek(0)

修改后的完整可运行代码：

from io import BytesIO  # 修正导入语句，原代码import BytesIO错误
from azure.storage.blob import BlobServiceClient

v_file = BytesIO()
for chunk in r.iter_content(chunk_size=1024 * 1024):
    if chunk:
        v_file.write(chunk)

# 关键：重置文件指针到起始位置
v_file.seek(0)

container_name = 'test'
blob_name = 'test_blob'
blob_service_client = BlobServiceClient.from_connection_string(connection_string)
blob_client = blob_service_client.get_blob_client(container=container_name, blob=blob_name)
blob_client.upload_blob(data=v_file, overwrite=True)

额外说明：

• 原代码里的import BytesIO是错误的，Python中BytesIO属于io模块，正确导入方式是from io import BytesIO
• 完全不需要把BytesIO内容写入本地文件，重置指针后直接上传就能实现无本地文件的流式上传

内容的提问来源于stack exchange，提问作者Man_Like_Dave