http-media-0.3.0: Processing HTTP Content-Type and Accept headers

Safe HaskellSafe-Inferred



Defines the Accept type class, designed to unify types on the matching functions in the Media module.



class Show a => Accept a where Source

Defines methods for a type whose values can be matched against each other in terms of an HTTP Accept-* header.

This allows functions to work on both the standard Accept header and others such as Accept-Language that still may use quality values.

Minimal complete definition

parseAccept, matches, moreSpecificThan


parseAccept :: ByteString -> Maybe a Source

Specifies how to parse an Accept-* header after quality has been handled.

showAccept :: a -> String Source

Specifies how to show an Accept-* header. Defaults to the standard show method.

Mostly useful just for avoiding quotes when rendering ByteStrings with accompanying quality.

matches :: a -> a -> Bool Source

Evaluates whether either the left argument matches the right one.

This relation must be a total order, where more specific terms on the left can produce a match, but a less specific term on the left can never produce a match. For instance, when matching against media types it is important that if the client asks for a general type then we can choose a more specific offering from the server, but if a client asks for a specific type and the server only offers a more general form, then we cannot generalise. In this case, the server types will be the left argument, and the client types the right.

For types with no concept of specificity, this operation is just equality.

moreSpecificThan :: a -> a -> Bool Source

Evaluates whether the left argument is more specific than the right.

This relation must be irreflexive and transitive. For types with no concept of specificity, this is the empty relation (always false).

mostSpecific :: Accept a => a -> a -> a Source

Evaluates to whichever argument is more specific. Left biased.