How can I generate the url programatically (JAVA) for downloading a file from my azure blob storage?

Question

Hello,

I am trying to generate a URL link to download the file uploaded to my container. I was able to generate the URL but when I used that URL it gave the following error.

<Error>
<Code>AuthenticationFailed</Code>
<Message>Server failed to authenticate the request. Make sure the value of Authorization header is formed correctly including the signature. </Message>
<AuthenticationErrorDetail>Signature did not match.</AuthenticationErrorDetail>
</Error>

I am using the following code to generate the SAS token.

BlobContainerSasPermission blobContainerSasPermission = new BlobContainerSasPermission()
                .setReadPermission(true)
        BlobServiceSasSignatureValues builder = new BlobServiceSasSignatureValues(OffsetDateTime.now().plusDays(1), blobContainerSasPermission)
                .setProtocol(SasProtocol.HTTPS_ONLY);
        BlobClient client = new BlobClientBuilder()
                .connectionString("connection string")
                .blobName("")
                .buildClient();
        String blobContainerName = "test";
        return String.format("https://%s.blob.core.windows.net/%s?%s",client.getAccountName(), blobContainerName, client.generateSas(builder));

I also tried to use the following code to generate the SAS token:-
CloudStorageAccount account = CloudStorageAccount.parse(blobConnectionString);

     // Create a blob service client
     CloudBlobClient blobClient = account.createCloudBlobClient();

     CloudBlobContainer container = blobClient.getContainerReference(containerName);

     Date expirationTime = Date.from(LocalDateTime.now().plusDays(7).atZone(ZoneOffset.UTC).toInstant());
    SharedAccessBlobPolicy sharedAccessPolicy=new SharedAccessBlobPolicy();
    sharedAccessPolicy.setPermissions(EnumSet.of(SharedAccessBlobPermissions.READ, 
        SharedAccessBlobPermissions.WRITE,SharedAccessBlobPermissions.ADD));
    sharedAccessPolicy.setSharedAccessStartTime(new Date());
    sharedAccessPolicy.setSharedAccessExpiryTime(expirationTime);

    String sasToken = container.generateSharedAccessSignature(sharedAccessPolicy, null);

But I got the same error everytime.
I went through all the solutions which I came across, but nothing seems to work. It would be great to receive some suggestions.

Answer 1

@Saurabh Patil
Please try the code below and see if it works for you:

    String connString = "<storage account connection string >";  
    String containerName = "<container name>";  
    String blobName = "<file name>";  

    BlobServiceClient client = new BlobServiceClientBuilder().connectionString(connString).buildClient();  
    BlobClient blobClient = client.getBlobContainerClient(containerName).getBlobClient(blobName);  

    BlobSasPermission blobSasPermission = new BlobSasPermission().setReadPermission(true);                                             
                                                                                           
    OffsetDateTime expiryTime = OffsetDateTime.now().plusDays(1);   
    BlobServiceSasSignatureValues values = new BlobServiceSasSignatureValues(expiryTime, blobSasPermission)  
                    .setStartTime(OffsetDateTime.now());  

    System.out.println(blobClient.generateSas(values));  

There is also a relevant thread on GitHub which you might find helpful. If you are still facing issues I recommend also posting your question on Stack Overflow so our developer community can also assist.

Hope this helps. Please let me know if you need further assistance.

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