Customize error responses

[lfborjas]

Try this! https://docs.servant.dev/en/stable/cookbook/custom-errors/CustomErrors.html

• For 500s and others: This apparently couldn't be done at the servant level, but easy to do at the warp level, by using runSettings with a custom settingsOnExceptionResponse -- we essentially just want a cute HTML page, instead of these plain text uglinessesses: https://hackage.haskell.org/package/warp-3.3.13/docs/src/Network.Wai.Handler.Warp.Settings.html#defaultOnExceptionResponse
• for 404, maybe this? https://geekingfrog.com/blog/post/custom-404-with-servant

Some more conversations about this: https://docs.servant.dev/en/stable/cookbook/custom-errors/CustomErrors.html (and issues here and here