Actions28
- Attachments Actions
- Comments Actions
- Import Actions
- Static Images Actions
- Forms Actions
- Delete form definition
- Update form definition metadata
- Get form definition by ID
- Add comment to form
- Get form data comments
- Download form as file
- Export forms to Storage
- Get form data details
- Update form data
- Delete form data
- Import form definition from another iTwin
- Get iTwin form definitions
- Add attachment to form
- Get form data attachments
- Create form data
- Get iTwin form data
- Get audit trail for form data
- List Groups Actions
- Templates Actions
- Workflows Actions
Overview
This node integrates with the iTwin Forms API, allowing users to interact with form data and attachments within the iTwin platform. Specifically, the "Get attachment file by ID" operation retrieves the binary file of a specific attachment associated with a form data instance. This is useful when you need to programmatically access or download files submitted as part of forms, such as images, documents, or other media.
Practical examples include:
- Automatically downloading and processing attachments submitted through forms.
- Archiving form attachments in external storage.
- Triggering workflows based on the content of attached files.
Properties
| Name | Meaning |
|---|---|
| ID | The ID of the form data instance for which to get an attachment. |
| Attachment ID | The ID of the attachment whose file you want to retrieve. |
Output
The node outputs the retrieved attachment file. The output structure includes:
- A
jsonfield containing metadata or result information about the operation. - The actual attachment file is expected to be available as binary data attached to the output item (typical for file retrieval nodes).
Since the source code does not explicitly show binary handling but this is a file retrieval operation, it is standard that the node outputs the attachment file as binary data under the binary property of the output item.
Dependencies
- Requires an API key credential for authenticating with the iTwin Forms API (configured in n8n as an OAuth2 credential).
- Internet access to reach the iTwin Forms API endpoints.
- The node depends on the bundled
FormsOpenApiInterpreterclass to handle API operations.
Troubleshooting
Common issues:
- Invalid or missing form data instance ID or attachment ID will cause errors.
- Authentication failures if the API credentials are not set up correctly.
- Network connectivity problems can prevent successful API calls.
Error messages:
"Unknown operation: <operation>": Indicates the specified operation name is invalid or unsupported.- API errors returned from the iTwin Forms service will be propagated; check the error message for details.
Resolutions:
- Verify that the IDs provided are correct and exist in the iTwin Forms system.
- Ensure the API authentication token is valid and has necessary permissions.
- Check network connectivity and proxy settings if applicable.
Links and References
- iTwin Developer Documentation
- Refer to the iTwin Forms API documentation for detailed information on form data and attachments.