Springboot: Unable to read the file after moving it to a storage container (Azure)

Question

Program Flow:

I have a set of high resolution image files a user uploads as part of his "Order". At the backend I'm moving those files to a permanent storage container (from a temporary container). This process is working fine.

New Requirement:

Create a thumbnail of the imge after moving it to the permanent storage container.

Following function is invoked to move the file and create the 300x300 image thumbnail:

public void moveFilesToNewContainer(OrderFile of, Order savedOrder, OrderFileRepository orderFileRepository) {
        int timestampLength = String.valueOf(System.currentTimeMillis()).length()+1;
        try {
            String filePath = of.getFilePath()
                    .replace(String.format("https://%s.blob.core.windows.net/%s/",
                            asAccountName, asTemporaryContainerName), "");

            String extension = CommonUtils.getFileExtension(filePath);
            String fileName = filePath.substring(timestampLength);

            String sasToken = fileService.generateSasToken(asTemporaryContainerName, filePath);
            String newFilePath = fileService.moveFileToNewPlace(asTemporaryContainerName, asFilesContainerName,
                    filePath, String.format("%s/%s", savedOrder.getOrderNo(), fileName), sasToken);

            // If file is of image type, generate a 300x300 thumbnail with _preview appended to its name
            if (CommonUtils.isImageType(extension)) {
                String pathWithoutExt = CommonUtils.removeFileExtension(newFilePath);
                Image thumbnailImage = generateImageThumbnail(newFilePath + '?' + sasToken);
                File destFileName = new File(pathWithoutExt + "_preview" + extension);
                ImageIO.write((RenderedImage) thumbnailImage, extension, destFileName);
            }

            of.setFilePath(URLDecoder.decode(newFilePath, StandardCharsets.UTF_8.name()));
            orderFileRepository.save(of);
        } catch (Exception ex) {
            log.error(ex.getMessage());
        }
    }

public Image generateImageThumbnail(String filePath) {
        try {
            File file = new File(filePath);
            BufferedImage image = ImageIO.read(file);
            Image newImage = image.getScaledInstance(300, 300, Image.SCALE_DEFAULT);
            return newImage;
        } catch(IOException e){
            System.out.println("Error: " + e);
        }
        return null;
    }

Function to generate sas token:

public String generateSasToken(String srcContainerStr, String srcBlobName) {
        BlobServiceClient blobServiceClient = getTmpBlobServiceClient();

        BlobContainerClient srcContainerClient = blobServiceClient.getBlobContainerClient(srcContainerStr);

        BlobClient srcBlobClient = srcContainerClient.getBlobClient(srcBlobName);
        BlobServiceSasSignatureValues sas = new BlobServiceSasSignatureValues(OffsetDateTime.now().plusMinutes(10),
                BlobContainerSasPermission.parse("r")
                        .setDeletePermission(true).setReadPermission(true).setWritePermission(true));
        String sasToken = srcBlobClient.generateSas(sas);
        return sasToken;
    }

Function that moves the file to the new container:

public String moveFileToNewPlace(String srcContainerStr, String destContainerStr,
                                     String srcBlobName, String destBlobName, String sasToken) {
        // Create a BlobServiceClient object which will be used to create a container client
        BlobServiceClient blobServiceClient = getTmpBlobServiceClient();

        BlobContainerClient srcContainerClient = blobServiceClient.getBlobContainerClient(srcContainerStr);
        BlobContainerClient destContainer = blobServiceClient.getBlobContainerClient(destContainerStr);

        BlobClient srcBlobClient = srcContainerClient.getBlobClient(srcBlobName);

        BlobClient destBlobClient = destContainer.getBlobClient(destBlobName);

        // Copy to new location
        destBlobClient.beginCopy(String.format("%s?%s", srcBlobClient.getBlobUrl(), sasToken), null);
        // Delete old file
        srcBlobClient.delete();

        return destBlobClient.getBlobUrl();
    }

The Problem:

Issue is when I try to read the file from the path (Exception: Can't read input file):

If I try to go directly to the URL from the browser, I get AuthenticationFailed :

Does anybody have a solution for this? I'm not an expert with Azure/ handling cloud storages and stuck on this for quite a while now. Any help would be really appreciated.

Thanks!

Answer 1

There are a few things I would try here:

• Give permissions for 'public' if you'd like to access the cloud storage file via URL without being on the same private network. You should also be able to configure this in your YAML file or Azure GUI
• As for the path try using back slashes instead of forward slashes in newFilePath; also, try using the "virtual directory" prefix
• Be sure to follow this guide: https://docs.microsoft.com/en-us/azure/developer/java/spring-framework/configure-spring-boot-starter-java-app-with-azure-storage

---

Resources:

https://docs.microsoft.com/en-us/azure/storage/blobs/anonymous-read-access-configure?tabs=portal

https://azure.microsoft.com/en-us/updates/choose-to-allow-or-disallow-blob-public-access-on-azure-storage-accounts/

https://docs.microsoft.com/en-us/azure/storage/files/storage-troubleshoot-windows-file-connection-problems?tabs=azure-portal