Use case: Read the download url for a file attachment of an annotation

Before you start

Before you retrieve a download URL for a file attachment, ensure you have completed the following prerequisites:

  1. Verify Permissions: Confirm that you have the necessary rights to access the attachment. This typically requires having read access to the annotation containing the attachment.
  2. Identify the Attachment: Have the unique identifier of the specific attachment you need to download. You'll need this to request the correct download URL.
  3. Understand URL Expiration: Be aware that download URLs provided by the Collaboration system are typically temporary and expire after a certain period (usually 24 hours or less). They should be used promptly rather than stored long-term.
  4. Storage Considerations: Ensure you have sufficient local storage if you plan to download large files, especially when implementing batch download functionality.
  5. Set Up SDK Environment: Ensure your Unity environment is properly configured with the Collaboration SDK to interact with the annotation system.

How do I...?

Get a download URL for a specific attachment

To retrieve a download URL for an identified attachment:

  1. Obtain the Project Identifier: Ensure you have the correct project identifier (GUID) for the project.
  2. Obtain the Asset Identifier: Ensure you have the correct and complete asset identifier (GUID) for the asset.
  3. Obtain the Attachment ID: Ensure you have the unique identifier for the specific attachment you want to get the download url for.
  4. Request the Download URL: Use the SDK to request a temporary download URL for the attachment.
  5. Use the URL Promptly: Remember that the download URL has a limited validity period.

Example:

var attachmentReference = new attachmentReference(projectId, annotationId, attachmentId);

var response = await annotationManagement.ReadAnnotationFileAttachmentDownloadUrlAsync(
  attachmentReference,
  cancellationToken);

var downloadUrl = response.Url;

The ReadAnnotationFileAttachmentDownloadUrlAsync method also accepts two optional parameters:

  • filePath: This value is required if there are multiple files associated with the same attachment
  • width: The desired width of the images.

For more information on working with attachments, see the documentation on creating attachments and updating attachments.

See the API documentation for more details on the ReadAnnotationFileAttachmentDownloadUrlAsync method.