How to read Azure Blob Url? - node.js

Question

I am creating list of blog posts in react and express/ Azure SQL db. I am able to use the Azure blob storage to store the image associated to the post. I am also able to get the blob url and I am storing that in my SQL db. However when I want to read the url directly it threw an error resource not found. After searching docs and other stackoverflow answers I could infer that it has something to do with SAS token. Can anyone explain what would be the better way to approach this?
https://yourdomain.blob.core.windows.net/imagecontainer/yourimage.png
Below is the nodejs code.
router.post('/image', async function (req, res) {
try {
console.log(req.files.files.data);
const blobName = 'test' + uuidv1() + '.png';
const containerClient = blobServiceClient.getContainerClient(containerName);
const blockBlobClient = containerClient.getBlockBlobClient(blobName);
const uploadBlobResponse = await blockBlobClient.upload(req.files.files.data, req.files.files.data.length)
res.send({tempUrl:blockBlobClient.url});
} catch (e) {
console.log(e);
}
})

Answer 1

However when I want to read the url directly it threw an error
resource not found.
Most likely you're getting this error because the blob container containing the blob has a Private ACL and because of that anonymous access is disabled. To enable anonymous access, please change the blob container's ACL to Blob or Public and that will solve this problem.
If you can't (or don't want to) change the blob container's ACL, other option would be to create a Shared Access Signature (SAS) on a blob. A SAS essentially gives time and permission bound access to a blob. For your needs, you would need to create a short-lived SAS token with just Read permission.
To generate a SAS token, you will need to use generateBlobSASQueryParameters method. Once you create a SAS token, you will need to append it to your blob's URL to get a SAS URL.
Here's the sample code to do so. It makes use of #azure/storage-blob node package.
const permissions = new BlobSASPermissions();
permissions.read = true;//Set read permission only.
const currentDateTime = new Date();
const expiryDateTime = new Date(currentDateTime.setMinutes(currentDateTime.getMinutes()+5));//Expire the SAS token in 5 minutes.
var blobSasModel = {
containerName: 'your-blob-container-name',
blobName: 'your-blob-name',
permissions: permissions,
expiresOn: expiryDateTime
};
const sharedKeyCredential = new StorageSharedKeyCredential('your-storage-account-name', 'your-storage-account-key');
const sasToken = generateBlobSASQueryParameters(blobSasModel, sharedKeyCredential);
const sasUrl = blockBlobClient + "?" + sasToken;//return this SAS URL to the client.