How to get file content (byte array) from azure file storage using CloudFileClient?

Question

I have file storage on azure and I am connecting and traversing threw the directories successfully. But I can't get the content of the file. For getting the FileClientReference I am using the following code:

public CloudFileClient getFileClientReference() {
    log.info("Logging into azure file storage:");
    CloudFileClient cloudFileClient = null;

    CloudStorageAccount storageAccount;
    try {
        storageAccount = CloudStorageAccount.parse(storageConnectionString);
        cloudFileClient = storageAccount.createCloudFileClient();
    } catch (IllegalArgumentException | URISyntaxException e) {
        log.error("Connection string specifies an invalid URI.");
        log.error("Please confirm the connection string is in the Azure connection string format.");
        throw new AzureFileStorageNotAvailableException("Failed to login to azure file storage.");
    } catch (InvalidKeyException e) {
        log.error("Connection string specifies an invalid key.");
        log.error("Please confirm the AccountName and AccountKey in the connection string are valid.");
        throw new AzureFileStorageNotAvailableException("Failed to login to azure file storage.");
    }
    log.info("Logged into azure file storage.");
    return cloudFileClient;
}

I have tested this code and it's working fine. I used it to traverse all the directories. What I am trying now to do is for a given url to get file content. The code that I am using to get the url is:

Iterable<ListFileItem> results = rootDir.listFilesAndDirectories();
    for (ListFileItem item : results) {
        boolean isDirectory = item.getClass() == CloudFileDirectory.class;
        final String uri = item.getUri().toString();
        if (isDirectory && uri.contains("myPath")) {
            traverseDirectories((CloudFileDirectory) item, azureFiles);
        } else if (!isDirectory) {
            handleFile(item, uri, azureFiles);
        }
    }

And in the end the result is something like:

https://appnamedev.file.core.windows.net/mystorage/2018/status/somepdf.pdf

Now I want to use this url to later get the file content as byte array and for that I am using the following code:

 fileClientReference.getShareReference(document.getPath())
                 .getRootDirectoryReference().getFileReference(document.getFileName()).openRead();

Where document.getPath() will point to the above mentioned path and document.getFileName() will give the file name: somepdf.pdf.

When I am calling this method I am getting an error:

Method threw 'com.microsoft.azure.storage.StorageException' exception.
The specifed resource name contains invalid characters.

The pdf is ok but I don't know how to access the pdf and get the content.

Answer 1

If anyone is also trying to figure out how to do this here is an answer: First when you are calling the method:

fileClientReference.getShareReference(document.getPath())

the path should be in the following format:

/folder1/folder2/folder3/

Without the prefix from azure:

https://appnamedev.file.core.windows.net

and without the file name as I was trying before. I have parsed that by calling replaceAll on the string.

In one method I have:

CloudFile cloudFile;
    try {
        String fileLocation = document.getPath().replaceAll(AZURE_FILE_STORAGE_URL_PREFIX + "|" + document.getFileName(), "");
        final CloudFileShare fileShare = fileClientReference.getShareReference(fileLocation);
        cloudFile = fileShare.getRootDirectoryReference().getFileReference(document.getFileName());
        return new AzureFile(document.getFileName(), readFileContent(cloudFile));
    } catch (URISyntaxException | StorageException e) {
        log.error("Failed to retrieve file for document with id: {}", documentId, e);
        throw new AzureFileStorageNotAvailableException("Failed to retrieve file");
    }

And the readFileContent method is:

private ByteArrayResource readFileContent(CloudFile cloudFile) {
    try (final FileInputStream fileInputStream = cloudFile.openRead()) {
        final byte[] content = fileInputStream.readAllBytes();
        return new ByteArrayResource(content);
    } catch (StorageException | IOException e) {
        log.error("Failed to read file content", e);
        throw new AzureFileStorageNotAvailableException("Failed to read file");
    }
}

The AzureFile is an entity that I have created on my own since I needed to pass the file name and the content:

@Data
@AllArgsConstructor
public class AzureFile {

    private String fileName;
    private ByteArrayResource content;
}

Answer 2

public static List<String> extractFileDataFromAzureFileShare(String fileName) throws IOException {
    ShareDirectoryClient directoryClient = new ShareFileClientBuilder()
            .endpoint("https://${accountName}.file.core.windows.net")
            .sasToken("${SASTokenQueryParams}")
            .shareName("${FileShareName}")
            .resourcePath("${FilePath}")
            .buildDirectoryClient();
    ShareFileClient fileClient = directoryClient.getFileClient(fileName);
    byte[] bytes = fileClient.openInputStream().readAllBytes();
    InputStream inputStream = new ByteArrayInputStream(bytes);
    return new BufferedReader(
            new InputStreamReader(inputStream, StandardCharsets.UTF_8))
            .lines()
            .collect(Collectors.toList());
}