File Events
The File Uploader Widget fires an event to the backend when files are successfully uploaded. The backend can use this event to process the uploaded files, run validation, update related records, or return an error response.
onFileUpload
Fired when one or more files have been successfully uploaded and linked to the form record.
The backend receives a request containing:
| Field | Description |
|---|---|
widgetName | The internal name of the file uploader field. |
widgetEvent | Always "onFileUpload" for this event. |
Backend Response
The backend can respond with:
- Validation errors — return a
FormValidationDataresponse to display error messages on the form if the uploaded files do not meet requirements (e.g., wrong format, size exceeded, business rule violations) - Standard success response — return a success response to confirm the upload was accepted
info
File uploads are processed as chunked transfers for large files. The onFileUpload event fires once all chunks have been received and the file is fully assembled on the server.