Senario: I have to submit a form to an external host, the external host responds with an email, and returns the the user to a confirmation page, which is hosted on my server (the url is included in the form data). The confirmation page url has a unique 'ticket number' appended to it by the external server. I cannot submit the form directly as I need to validate the form before submission to the external site, using php.
So I need to catch the form submission, check that the required fields are filled in, using server side code, and then forward the data as a POST to the external server. The user is then shown the confirmation page.
I have succeded in doing this using a JS self submitting form, but I need to forward files uploaded on the original form, is it possible to forward uploaded files using this method?
Alternatively, I have tried CURL, fputs, and stream_get_contents. However is it possible to use a serverside approach and have the confirmation page displayed to the client as they didn't initiate the request?