Documentation

A representation of the response(s) that a Servant endpoint can return.

Under the hood, Responses is a Some Response. This allows for the possibility that an endpoint might return one of several responses, via UVerb.

Note that a Response consists of a return body type, as well as the return headers.

The endpoint will not return a response.

There is only one possible response. Equivalent to a single ReqBody _ a.

The endpoint may return one of multiple multiple (>1) responses. Equivalent to a UVerbs with more than one type.

A representation of one possible response that a Servant endpoint can return.

Currently, the only situation in which multiple Responses can be returned is using the UVerb combinator. This bundles response types together with response Headers, so we do the same here.

Convenience optic to traverse over all the Responses within a Responses.

Get a term-level response from a type-level argument. This encodes the argument(s) of a Verb or UVerb.

Similar to Typeable, but also get the response Headers.

Witness that all members of a type-level list are instances of HasResponse.

This class does 2 things:

• It lets us get a term-level list of Responses from a type-level list of types, all of which have HasResponse instances.
• More impressively, its instances enforce that getResponses will only type-check for type-level lists of length 2 or more. This is because AllHasResponse will only ever be used by oneOfResponses, which is the only way to construct a Many @Response and thus lets us enforce the invariant that its list arguments will always have more than 1 element. This lets us make sure that there's only ever one way to represent a list of Responses using Responses.

Of course, someone might import this Internal module and define a HasResponse a => AllHasResponse '[a] instance. Don't do that.