Inconsistencies in error handling between backends about rest

[hesselink]

Isn't this just how the backends handle exceptions by default?

[bergmark]

Probably, but I think we should change it. At the moment a lot of errors are lost when using rest-happstack.

[dpwiz]

Take a note that error messages can leak sensitive information...

[hesselink]

So this is an issue mostly with happstack, because it uses lazy bytestrings. That means that if there is an undefined or something in the computation that produces a response, you might lose the error, even if you have a top level exception handler around your code. rest inherits this limitation, since it also uses a lazy bytestring. So I think it's up to users to handle this, with a top level exception handler and optionally forcing the response body if you want to be sure you catch everything.

[bergmark]

Is there anything we can actually do about this in rest? It sounds to me that users just have to pick a backend that does this properly. We can probably close this.

[hesselink]

We could switch rest to use some kind of streaming abstraction (pipes, conduit, io-streams). Then I think wai and snap could handle this correctly. I'm not sure how much work this would be. A lot of it would just be choosing what to use and seeing how it impacts the whole framework, I guess.

[bergmark]

wai already does this well enough, and snap-1.0 should also fix it.

[hesselink]

OK, let's close it then.