Error handling in custom httphandler

Hi,

I'm copying the reply to your support here for community reference.

My recommendation for your scenario is to treat the "file exists" condition as a validation error.
The idea is to distinguish between this and scenarios where the request genuinely fails. The user should still be able to retry the upload in the latter case.

Successful uploads, on the other hand, should just trigger validation messages. There's no point in retrying them anyway.
You should still return a 200 OK response from the server plus metadata as JSON.
The detailed process of sending and receiving metadata as part of the response is covered in this help topic.

The validation error can be displayed on the side or by manipulating the file entry markup. See also the template demo.

Regards,
T. Tsonev
Telerik