Generate SAS token

Endpoint

GET /api/generateSASToken

Description

This function generates a Shared Access Signature (SAS) token for secure, time-limited access to the Azure Blob Storage “images” container. The token grants read, write, and create permissions.

Request

No parameters required. This is a simple GET request.

Response

string

A SAS token string that can be appended to Azure Blob Storage URLs for authenticated access. The token is valid for 30 minutes from generation time.

Behavior

Connects to Azure Blob Storage using shared key credentials
Configures permissions: read, write, and create
Sets expiry time to 30 minutes from the current time
Generates and returns the SAS token query parameters as a string

Example request

const response = await fetch('/api/generateSASToken', {
  method: 'GET'
});

const sasToken = await response.text();
console.log(sasToken);
// Example: "sv=2021-08-06&ss=b&srt=sco&sp=rwc&se=2024-03-04T18:30:00Z&st=2024-03-04T18:00:00Z&spr=https&sig=..."

// Use the token with blob URLs
const imageUrl = `https://account.blob.core.windows.net/images/photo.png?${sasToken}`;

Token permissions

The generated SAS token includes the following permissions:

Read: Access to read blob content and metadata
Write: Ability to write or overwrite blobs
Create: Permission to create new blobs

Token expiry

Tokens are valid for 30 minutes from generation time:

const expiryDate = new Date();
expiryDate.setMinutes(expiryDate.getMinutes() + 30);

Implementation details

The underlying implementation uses Azure’s generateBlobSASQueryParameters function:

const permissions = new BlobSASPermissions();
permissions.write = true;
permissions.read = true;
permissions.create = true;

const expiryDate = new Date();
expiryDate.setMinutes(expiryDate.getMinutes() + 30);

const sasToken = generateBlobSASQueryParameters({
  containerName: containerClient.containerName,
  permissions: permissions.toString(),
  expiresOn: expiryDate,
},
  sharedKeyCredential
).toString();

The token must be regenerated after expiry to maintain access to blob storage resources.

REST API

Azure Functions

Components

Endpoint

Description

Request

Response

Behavior

Example request

Token permissions

Token expiry

Implementation details

​Endpoint

​Description

​Request

​Response

​Behavior

​Example request

​Token permissions

​Token expiry

​Implementation details

Endpoint

Description

Request

Response

Behavior

Example request

Token permissions

Token expiry

Implementation details