Django return blob form azure-storage as downloadable file

Question

I am new to azure-storage and django My dev environment software configuration is as- django 1.10 , python 2.7.6, azure-storage-blob 0.37. I am using django application as webservice api and frontend is built using angular-2 and HTML

I am using azure blob storage for storing files with any type.

azure blob Container where which I am saving files have private access only.I am able to upload file successfully.

The problem is while downloading file- what I am trying to achieve is-

1. When someone clicks on hyperlink on page request will go to django view with blob name. then I can get blob using container name and blob name

   block_blob_service._get_blob(container,blob_name)

2. I want to return that blob as downloadable file in django response.

Can you suggest be solution or better approach where I can achieve this.

Thanks in advance.

Answer 1

I suggest you using Azure Storage System in Django.

Please follow this tutorial to configure your azure storage account in your project.

# Replace <...> appropriately with your information

# AzureStorage Settings
AZURE_STORAGE_ACCOUNT = "<account_name>"
AZURE_STORAGE_KEY = "<account_key>"
AZURE_STORAGE_CONTAINER = "<default_storage_container>" # statics will use this container

# Static Settings
STATICFILES_STORAGE = "<my_project>.storage.AzureStorage"
STATIC_URL = "http://<storage account>.blob.core.windows.net/<default_storage_container>/"

# Media Settings
MEDIA_URL = 'http://storage.pepperdeck.com/<media_container>/'

You could get more details here and here.

---

Update Answer: Actually,The Django-Azure-Storage I provided yesterday is essentially a adapter call for azure storage SDK . The media container you mentioned in your reply is actually don't need to be configured , because you only refer to azure storage.

According to you needs , just use Azure Storage Python SDK.

Please follow the steps below.

Step1: Bind the name of your blob which you want to download to your hyperlink, and pass the blob name as a parameter to the backend when the user clicks.

Step2: Get blob url.

def GetBlobUrl():
    blobService = BlockBlobService(account_name=accountName, account_key=accountKey)
    sas_token = blobService.generate_container_shared_access_signature(containerName,ContainerPermissions.READ, datetime.utcnow() + timedelta(hours=1))
    # print url
    return 'https://' + <your_account_name> + '.blob.core.windows.net/' + <your_container_name> + '/<your_blob_name>?' + sas_token

Step3: Download a file in a browser via StreamingHttpResponse.

import requests
from django.http import StreamingHttpResponse

def stream_file(request, *args, **kwargs):
    file_url = "<blob url you get in the Previous step >"

    r = requests.get(file_url, stream=True)

    resp = StreamingHttpResponse(streaming_content=r)
    resp['Content-Disposition'] = 'attachment; filename="<your blob name>"'

You could also refer to the threads below:

1.Stream file from remote url to Django view response

2.how to stream file to client in django

Hope it helps you.

Answer 2

I can add my few cents to @Jay Gong answer.

1st Answer

This is solution for azure-storage-blob v12.

azure-storage-blob==12.8.1

import requests

from django.http import StreamingHttpResponse

from app_module.settings import AZURE_ACCOUNT_KEY # blob storage access key
from app_module.settings import AZURE_ACCOUNT_NAME # blob storage name
from app_module.settings import AZURE_CONTAINER # name of container
from app_module.settings import AZURE_ENDPOINT_SUFFIX # "core.windows.net"


def get_blob_url(file_path):
    sas_token = generate_account_sas(
        account_name=AZURE_ACCOUNT_NAME,
        account_key=AZURE_ACCOUNT_KEY,
        resource_types=ResourceTypes(service=True, container=True, object=True),
        permission=AccountSasPermissions(read=True),
        expiry=datetime.utcnow() + timedelta(hours=1)
    )

    return f'https://{AZURE_ACCOUNT_NAME}.blob.{AZURE_ENDPOINT_SUFFIX}/{AZURE_CONTAINER}/{file_path}?{sas_token}'


def download(request):
    file_name = 'example.png'
    file_location_in_blob = '/path/to/file/inside/blob/storage/' + file_name

    url = get_blob_url(file_location_in_blob)

    request = requests.get(url, stream=True)
    response = StreamingHttpResponse(streaming_content=request)

    response['Content-Disposition'] = f'attachment; filename={file_name}'

    return response

2nd Answer

This is solution for azure-storage-blob v2. It's more elegant since you don't have to build streaming response.

azure-storage-blob==2.1.0 

from django.http import HttpResponse

def download(request):
    object = Model.objects.last()
    
    # file is FileField or its deriveritives ImageField
    response = HttpResponse(object.file) 
    response['Content-Disposition'] = f'attachment; filename={file_name}'

    return response