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    Class AzureFileStorage

    Azure Blob Storage implementation of the FileStorageBase interface.

    This class provides methods for interacting with Azure Blob Storage as a file storage provider. It implements all the abstract methods defined in FileStorageBase and handles Azure-specific authentication, authorization, and file operations.

    It requires the following environment variables to be set:

    • STORAGE_AZURE_CONTAINER: The name of the Azure Storage container
    • STORAGE_AZURE_ACCOUNT_NAME: The Azure Storage account name
    • STORAGE_AZURE_ACCOUNT_KEY: The Azure Storage account key
    // Create an instance of AzureFileStorage
    const azureStorage = new AzureFileStorage();

    // Generate a pre-authenticated upload URL
    const { UploadUrl } = await azureStorage.CreatePreAuthUploadUrl('documents/report.pdf');

    // Generate a pre-authenticated download URL
    const downloadUrl = await azureStorage.CreatePreAuthDownloadUrl('documents/report.pdf');

    // List files in a directory
    const files = await azureStorage.ListObjects('documents/');

    Hierarchy (View Summary)

    Index

    Constructors

    constructor

    Properties

    _accountId _accountName providerName

    Accessors

    AccountId AccountName IsConfigured SupportsStreaming

    Methods

    CopyObject CreateDirectory CreatePreAuthDownloadUrl CreatePreAuthUploadUrl DeleteDirectory DeleteObject DirectoryExists GetObject GetObjectMetadata GetObjectStream initialize ListObjects MoveObject ObjectExists PutObject SearchFiles throwUnsupportedOperationError

    Constructors

    Properties

    Protected_accountId

    _accountId: string

    The ID of the FileStorageAccount this driver instance is operating for. Set during initialization via the config parameter.

    Protected_accountName

    _accountName: string

    The name of the FileStorageAccount (for logging/display purposes).

    providerName: "Azure Blob Storage" = 'Azure Blob Storage'

    The name of this storage provider, used in error messages

    Accessors

    • get AccountId(): string

      Gets the account ID this driver instance is operating for. Returns undefined if the driver was not initialized with an account.

      Returns string

    • get AccountName(): string

      Gets the account name this driver instance is operating for. Returns undefined if the driver was not initialized with an account.

      Returns string

    • get IsConfigured(): boolean

      Checks if Azure Blob provider is properly configured. Returns true if account name, account key, and container name are present. Logs detailed error messages if configuration is incomplete.

      Returns boolean

    Methods

    • Copies a blob within Azure Blob Storage.

      This method creates a copy of a blob at a new location without removing the original. It uses a SAS URL to provide the source blob access for the copy operation.

      Parameters

      • sourceObjectName: string

        The name of the blob to copy

      • destinationObjectName: string

        The name to assign to the copied blob

      Returns Promise<boolean>

      A Promise resolving to a boolean indicating success

      // Create a backup copy of an important file
      const copied = await azureStorage.CopyObject(
        'documents/contract.pdf',
        'backups/contract_2024-05-16.pdf'
      );

      if (copied) {
        console.log('File copied successfully');
      } else {
        console.log('Failed to copy file');
      }

    • Creates a directory (virtual) in Azure Blob Storage.

      Since Azure Blob Storage doesn't have a native directory concept, this method creates a zero-byte blob with a trailing slash to simulate a directory. The blob has a special content type to indicate it's a directory.

      Parameters

      • directoryPath: string

        The path of the directory to create

      Returns Promise<boolean>

      A Promise resolving to a boolean indicating success

      // Create a new directory structure
      const created = await azureStorage.CreateDirectory('documents/reports/annual/');

      if (created) {
        console.log('Directory created successfully');
      } else {
        console.log('Failed to create directory');
      }

    • Creates a pre-authenticated download URL for a blob in Azure Blob Storage.

      This method generates a Shared Access Signature (SAS) URL that allows for downloading a blob without needing the Azure Storage account credentials. The URL is valid for 10 minutes and can only be used for reading the specified blob.

      Parameters

      • objectName: string

        The name of the blob to download (including any path/directory)

      Returns Promise<string>

      A Promise resolving to the download URL

      // Generate a pre-authenticated download URL for a PDF file
      const downloadUrl = await azureStorage.CreatePreAuthDownloadUrl('documents/report.pdf');

      // The URL can be shared with users or used in applications for direct download
      console.log(downloadUrl);

    • Creates a pre-authenticated upload URL for a blob in Azure Blob Storage.

      This method generates a Shared Access Signature (SAS) URL that allows for uploading a blob without needing the Azure Storage account credentials. The URL is valid for 10 minutes and can only be used for writing the specified blob.

      Parameters

      • objectName: string

        The name of the blob to upload (including any path/directory)

      Returns Promise<CreatePreAuthUploadUrlPayload>

      A Promise resolving to an object with the upload URL

      // Generate a pre-authenticated upload URL for a PDF file
      const { UploadUrl } = await azureStorage.CreatePreAuthUploadUrl('documents/report.pdf');

      // The URL can be used with tools like curl to upload the file
      // curl -H "x-ms-blob-type: BlockBlob" --upload-file report.pdf --url "https://accountname.blob.core.windows.net/container/documents/report.pdf?sastoken"
      console.log(UploadUrl);

    • Deletes a directory (virtual) and optionally its contents from Azure Blob Storage.

      For non-recursive deletion, this method simply deletes the directory placeholder blob. For recursive deletion, it lists all blobs with the directory path as prefix and deletes them all, including the directory placeholder.

      Parameters

      • directoryPath: string

        The path of the directory to delete

      • recursive: boolean = false

        If true, deletes all contents recursively (default: false)

      Returns Promise<boolean>

      A Promise resolving to a boolean indicating success

      // Delete an empty directory
      const deleted = await azureStorage.DeleteDirectory('documents/temp/');

      // Delete a directory and all its contents
      const recursivelyDeleted = await azureStorage.DeleteDirectory('documents/old_projects/', true);

    • Deletes a blob from Azure Blob Storage.

      This method attempts to delete the specified blob if it exists. It returns true if the blob was successfully deleted or if it didn't exist.

      Parameters

      • objectName: string

        The name of the blob to delete (including any path/directory)

      Returns Promise<boolean>

      A Promise resolving to a boolean indicating success

      // Delete a temporary file
      const deleted = await azureStorage.DeleteObject('temp/report-draft.pdf');

      if (deleted) {
        console.log('File successfully deleted');
      } else {
        console.log('Failed to delete file');
      }

    • Checks if a directory (virtual) exists in Azure Blob Storage.

      Since Azure Blob Storage doesn't have a native directory concept, this method checks for either:

      1. The existence of a directory placeholder blob (zero-byte blob with trailing slash)
      2. The existence of any blobs with the directory path as a prefix

      Parameters

      • directoryPath: string

        The path of the directory to check

      Returns Promise<boolean>

      A Promise resolving to a boolean indicating if the directory exists

      // Check if a directory exists before trying to save files to it
      const exists = await azureStorage.DirectoryExists('documents/reports/');

      if (!exists) {
        console.log('Directory does not exist, creating it first');
        await azureStorage.CreateDirectory('documents/reports/');
      }

      // Now safe to use the directory
      await azureStorage.PutObject('documents/reports/new-report.pdf', fileData);

    • Downloads a blob's content from Azure Blob Storage.

      This method retrieves the full content of a blob and returns it as a Buffer for processing in memory.

      Parameters

      • params: GetObjectParams

        Object identifier (objectId and fullPath are equivalent for Azure Blob)

      Returns Promise<Buffer>

      A Promise resolving to a Buffer containing the blob's data

      Error if the blob doesn't exist or cannot be downloaded

      try {
        // For Azure Blob, objectId and fullPath are the same (both are the blob name)
        const content = await azureStorage.GetObject({ fullPath: 'documents/config.json' });
        // Or equivalently:
        const content2 = await azureStorage.GetObject({ objectId: 'documents/config.json' });

        // Parse the JSON content
        const config = JSON.parse(content.toString('utf8'));
        console.log('Configuration loaded:', config);
      } catch (error) {
        console.error('Failed to download file:', error.message);
      }

    • Retrieves metadata for a specific blob in Azure Blob Storage.

      This method fetches the properties of a blob without downloading its content, which is more efficient for checking file attributes like size, content type, and last modified date.

      Parameters

      Returns Promise<StorageObjectMetadata>

      A Promise resolving to a StorageObjectMetadata object

      Error if the blob doesn't exist or cannot be accessed

      try {
        // For Azure Blob, objectId and fullPath are the same (both are the blob name)
        const metadata = await azureStorage.GetObjectMetadata({ fullPath: 'documents/report.pdf' });
        // Or equivalently:
        const metadata2 = await azureStorage.GetObjectMetadata({ objectId: 'documents/report.pdf' });

        console.log(`File: ${metadata.name}`);
        console.log(`Size: ${metadata.size} bytes`);
        console.log(`Last modified: ${metadata.lastModified}`);
      } catch (error) {
        console.error('File does not exist or cannot be accessed');
      }

    • Initialize Azure Blob Storage provider.

      Always call this method after creating an instance.

      Parameters

      • Optionalconfig: StorageProviderConfig

        Optional. Omit to use env vars, provide to override with database creds.

      Returns Promise<void>

      Simple Deployment (Environment Variables)
      const storage = new AzureFileStorage(); // Constructor loads env vars
      await storage.initialize(); // No config - uses env vars
      await storage.ListObjects('/');

      Multi-Tenant (Database Credentials)
      const storage = new AzureFileStorage();
      await storage.initialize({
        accountId: '12345',
        accountName: 'Azure Account',
        accountName: 'myaccount',
        accountKey: '...',
        defaultContainer: 'my-container'
      });

    • Lists blobs with the specified prefix in Azure Blob Storage.

      This method returns a list of blobs (files) and virtual directories under the specified path prefix. Since Azure Blob Storage doesn't have actual directories, this method simulates directory structure by looking at blob names with common prefixes and using the delimiter to identify "directory" paths.

      Parameters

      • prefix: string

        The path prefix to list blobs from (e.g., 'documents/')

      • delimiter: string = '/'

        The character used to simulate directory structure, defaults to '/'

      Returns Promise<StorageListResult>

      A Promise resolving to a StorageListResult containing objects and prefixes

      // List all files and directories in the documents folder
      const result = await azureStorage.ListObjects('documents/');

      // Process files
      for (const file of result.objects) {
        console.log(`File: ${file.name}, Size: ${file.size}, Type: ${file.contentType}`);
      }

      // Process subdirectories
      for (const dir of result.prefixes) {
        console.log(`Directory: ${dir}`);
      }

    • Moves a blob from one location to another within Azure Blob Storage.

      Since Azure Blob Storage doesn't provide a native move operation, this method implements move as a copy followed by a delete operation. It first copies the blob to the new location, and if successful, deletes the blob from the original location.

      Parameters

      • oldObjectName: string

        The current name/path of the blob

      • newObjectName: string

        The new name/path for the blob

      Returns Promise<boolean>

      A Promise resolving to a boolean indicating success

      // Move a file from drafts to published folder
      const success = await azureStorage.MoveObject(
        'drafts/report.docx',
        'published/final-report.docx'
      );

      if (success) {
        console.log('File successfully moved');
      } else {
        console.log('Failed to move file');
      }

    • Checks if a blob exists in Azure Blob Storage.

      This method verifies the existence of a blob without downloading its content, which is efficient for validation purposes.

      Parameters

      • objectName: string

        The name of the blob to check

      Returns Promise<boolean>

      A Promise resolving to a boolean indicating if the blob exists

      // Check if a file exists before attempting to use it
      const exists = await azureStorage.ObjectExists('documents/report.pdf');

      if (exists) {
        console.log('File exists, proceeding with download');
        const content = await azureStorage.GetObject('documents/report.pdf');
        // Process the content...
      } else {
        console.log('File does not exist');
      }

    • Uploads data to a blob in Azure Blob Storage.

      This method directly uploads a Buffer of data to a blob with the specified name. It's useful for server-side operations where you already have the data in memory.

      Parameters

      • objectName: string

        The name to assign to the uploaded blob

      • data: Buffer

        The Buffer containing the data to upload

      • OptionalcontentType: string

        Optional MIME type for the blob (inferred from name if not provided)

      • Optionalmetadata: Record<string, string>

        Optional key-value pairs of custom metadata to associate with the blob

      Returns Promise<boolean>

      A Promise resolving to a boolean indicating success

      // Upload a text file
      const content = Buffer.from('Hello, World!', 'utf8');
      const uploaded = await azureStorage.PutObject(
        'documents/hello.txt',
        content,
        'text/plain',
        { author: 'John Doe', department: 'Engineering' }
      );

      if (uploaded) {
        console.log('File uploaded successfully');
      } else {
        console.log('Failed to upload file');
      }

    • Search is not supported by Azure Blob Storage. Blob Storage is an object storage service without built-in search capabilities.

      To search Azure Blob Storage objects, consider:

      • Using Azure Cognitive Search to index blob content
      • Maintaining a separate search index (Azure Search, Elasticsearch, etc.)
      • Using blob metadata and tags for filtering with ListObjects
      • Using Azure Data Lake Analytics for complex queries

      Parameters

      • query: string

        The search query (not used)

      • Optionaloptions: FileSearchOptions

        Search options (not used)

      Returns Promise<FileSearchResultSet>

      UnsupportedOperationError always

    • Helper method to throw an UnsupportedOperationError with appropriate context. This method simplifies implementation of methods not supported by specific providers.

      Parameters

      • methodName: string

        The name of the method that is not supported

      Returns never

      UnsupportedOperationError with information about the unsupported method and provider

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