Network.HTTP.Kinder.Query

A request can be thought of as having a query component which is a mapping from a set of query keys (which are just strings) to values of QueryKeyState Text.

This module provides tools for extracting information from this mapping or constructing them.

Classes for encoding and decoding

class QueryEncode s a where

Determines a representation of a query value for a given query key.

Methods

queryEncode :: sing s -> a -> QueryKeyState Text

Instances

QueryEncode s Flag

QueryEncode s a => QueryEncode s (Maybe a)

QueryEncode s (Raw Text)

QueryEncode s a => QueryEncode s (QueryKeyState a)

class QueryDecode s a where

Attempts to parse a representation of a query value at a given query key.

Methods

queryDecode :: sing s -> QueryKeyState Text -> Either String a

Instances

QueryDecode s Flag

This instance act "strictly" in that if the key is present but given a value then it will fail to parse for this type. To be lenient use QueryKeyState directly.

QueryDecode s a => QueryDecode s (Maybe a)

QueryDecode s (Raw Text)

QueryDecode s a => QueryDecode s (QueryKeyState a)

Listing constraints to type-level lists

type family AllQueryEncodes hs :: Constraint

For a given concrete type a, a list of pairs ts satisfies AllQueryEncode a ts if each (n, a) in ts has QueryEncode n a.

Equations

AllQueryEncodes `[]` = ()

AllQueryEncodes (`(s, a)` : hs) = (QueryEncode s a, AllQueryEncodes hs)

type family AllQueryDecodes hs :: Constraint

For a given concrete type a, a list of pairs ts satisfies AllQueryDecode a ts if each (n, a) in ts has QueryDecode n a.

Equations

AllQueryDecodes `[]` = ()

AllQueryDecodes (`(s, a)` : hs) = (QueryDecode s a, AllQueryDecodes hs)

Types for encoding/decoding request queries

data QueryKeyState a

QueryKeyState describes the state of a given key within a query-map. The key may be complete absent, it may exist without a value, or it may exist with some value at a given type.

Constructors

QueryKeyPresent

QueryKeyValued a

QueryKeyAbsent

Instances

Monad QueryKeyState

Monad instance equivalent to Either Bool

Functor QueryKeyState

Applicative QueryKeyState

QueryDecode s a => QueryDecode s (QueryKeyState a)

QueryEncode s a => QueryEncode s (QueryKeyState a)

Eq a => Eq (QueryKeyState a)

Ord a => Ord (QueryKeyState a)

Read a => Read (QueryKeyState a)

Show a => Show (QueryKeyState a)

data Flag

Flag provides semantics for query parameters which may merely exist without actually storing a value---"flag" semantics.

Constructors

Here

NotHere

Instances

QueryDecode s Flag

This instance act "strictly" in that if the key is present but given a value then it will fail to parse for this type. To be lenient use QueryKeyState directly.

QueryEncode s Flag

Extra serialization utilities

queryEncodePair :: (KnownSymbol n, QueryEncode n a) => Sing n -> a -> Maybe (Text, Maybe Text)

Produces a pair of (name, representation) from a given query encoding.