wai-request-spec (hackage): WAI Request Spec is a declarative validation layer for HTTP requests. It aims to make error-handling for malformed requests as easy as taking the happy path.  A brief summary of the core features:  Can specify headers and query params as input sources  Support for parsing ints, floats, text, bytes (with encodings), and bools  A parser combinator interface for chaining together request requirements  Support for Alternatives  Support for optional parameters  Convenient and informative default error messages that let service consumers know what went wrong  It is built on WAI, so it is compatible with several Haskell web frameworks. All you need is the ability to access the Request object, and WAI Request Spec takes care of the rest!
Keywords: bsd3|library|network|wai