Add Typeform backend

[ghost]

Tried to setup Typeform example form through Fly Sites in UI, but Preview link took me back to https://www.typeform.com/. Could this be because it's a free account and the form is private?

Typeform URL: https://kittybot.typeform.com/to/Su91j4

[mrkurt]

TypeForm might be tough as a backend. I don't think it'll work at all with a private form. We'll need a list of forms to run tests against, most likely.

For this type of app, the basic steps to making it work as a backend are:

• Find the right combination of Host and X-Forwarded-Host headers to get it to respond without a redirect. You can test this using something like curl -D - -o /dev/null -sS https://kittybot.typeform.com/to/Su91j4 -H "X-Forwarded-Host: somecustomdomain.com" -H "kittybot.typeform.com"
• Once you have curl returning HTTP/1.1 200, you can build a proxy function in the CDN to send requests there.
• Lots of these types of apps need URLs in HTML or JavaScript/CSS to be rewritten. The best way to figure out where things are breaking is to load up a proxy version in the browser, see what images and styles are missing, then click around and see if there's anything that sends you to
  .typeform.com.

[ghost]

Quick note: Updating the form to "public" did not fix the problem on my end. Will work through the above.. Thanks!

[mrkurt]

@WesleyDavid and I poked at this yesterday, this seems like what it takes to do a basic Typeform backend: https://gist.github.com/mrkurt/cbe97a7674d5edc7704e4ce925d4f8e1