How to Create a Downloadable File from Azure

Azure Blob Storage allows you to generate a Shared Access Signature (SAS) token, which provides secure, time-limited access to your blobs (files) without sharing your account key. This guide will walk you through the steps to create a downloadable link using a SAS token.

Using Portal:

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Step 1: Log in to the Azure Portal

1. Go to the Azure Portal.
2. Log in with your Azure account credentials.

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Step 2: Navigate to Your Storage Account

1. In the Azure Portal, search for “Storage accounts” in the search bar at the top.
2. Click on “Storage accounts” in the search results.
3. Select the storage account that contains the blob (file) you want to share.

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Step 3: Access the Blob Service

1. In the storage account overview, scroll down to the “Blob service” section in the left-hand menu.
2. Click on “Containers” to view the list of containers in your storage account.
3. Select the container that holds the blob you want to create a link for.

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Step 4: Generate the SAS Token

1. Inside the container, find and click on the blob (file) you want to share.
2. At the top of the blob’s properties window, click on “Generate SAS” (sometimes labeled as “Shared Access Signature”).
3. In the SAS token generation window, configure the following options:
   • Permissions: Select the permissions you want to grant. For a downloadable link, you typically need Read permissions.
   • Start and Expiry Date/Time: Set the start time and expiry time for the token. This defines how long the link will be valid.
4. After configuring the settings, click “Generate SAS token and URL”.

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Step 5: Copy the SAS URL

1. Once the SAS token and URL are generated, you’ll see a URL in the “Blob SAS URL” field.
2. Copy the entire URL. This is your downloadable link.

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Using Azure SDK for Python

You can use the azure-storage-blob library to generate a SAS token programmatically with python:

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Installation

First, install the Azure Blob Storage SDK for Python:

pip install azure-storage-blob

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Python Code Example

from azure.storage.blob import BlobServiceClient, generate_blob_sas, BlobSasPermissions
from datetime import datetime, timedelta

# Set your connection string and container details
connection_string = "your_connection_string"
container_name = "your_container_name"
blob_name = "your_blob_name.txt"

# Create a BlobServiceClient object
blob_service_client = BlobServiceClient.from_connection_string(connection_string)

# Generate a SAS token for the blob
sas_token = generate_blob_sas(
    account_name=blob_service_client.account_name,
    container_name=container_name,
    blob_name=blob_name,
    account_key=blob_service_client.credential.account_key,
    permission=BlobSasPermissions(read=True),
    expiry=datetime.utcnow() + timedelta(hours=1)  # SAS token valid for 1 hour
)

# Construct the full URL with the SAS token
blob_url = f"https://{blob_service_client.account_name}.blob.core.windows.net/{container_name}/{blob_name}?{sas_token}"

print(f"SAS URL: {blob_url}")