从Azure Blob存储中返回Blob但不保存它

Question

I am trying to get the blob from Azure blob storage and return the files to the user for download.

Now what I am trying to do is to get the file from azure, save it locally, and return the file as using Static file:

   def getDownload(filename):
        try:
            file = blob.get_blob('picture', filename)
            with open(filename, 'w') as f:
                f.write(file)
        except:
            abort(400, 'Download blob fail')
        return static_file(filename, root='.', download=filename)

What I am trying to do it to stream it to user without first saving the file in the server.

How can I achieve it?

Answer 1

Unfortunately I don't have any python sample code, but here is what you can do for verification purposes:

1. Make sure the container is not publicly accessible
2. Client sends a request to your web application for a given file inside the blob to your web application
3. Verify if this client is allowed to access that blob (return a 401 error, if not)
4. Create a Shared Access Signature for this blob for a short timeframe (approx. 5 mins should do)
5. Return a 303 (see other) html status code to the client containing the url to the blob in the Location-Header

Example:

Client requests http://myservice.cloudapp.net/blobs/somefile.ext and is verified to access the resource. Then he will be redirected to http://mystorage.blob.core.windows.net/container/somefile.ext?SHARED_ACCESS_SIGNATURE . This link is only available to that client for a few minutes.