http-api-data-0.5: Converting to/from HTTP API data like URL pieces, headers and query parameters.
Safe Haskell None
Language Haskell2010

Web.Internal.FormUrlEncoded

Synopsis

Documentation

>>> :set -XDeriveGeneric
>>> :set -XOverloadedLists
>>> :set -XOverloadedStrings
>>> :set -XFlexibleContexts
>>> :set -XScopedTypeVariables
>>> :set -XTypeFamilies
>>> import Data.Char (toLower)
>>> data Person = Person { name :: String, age :: Int } deriving (Show, Generic)
>>> instance ToForm Person
>>> instance FromForm Person
>>> data Post = Post { title :: String, subtitle :: Maybe String, comments :: [String]} deriving (Generic, Show)
>>> instance ToForm Post
>>> instance FromForm Post
>>> data Project = Project { projectName :: String, projectSize :: Int } deriving (Generic, Show)
>>> let myOptions = FormOptions { fieldLabelModifier = map toLower . drop (length ("project" :: String)) }
>>> instance ToForm Project where toForm = genericToForm myOptions
>>> instance FromForm Project where fromForm = genericFromForm myOptions

class ToFormKey k where Source #

Typeclass for types that can be used as keys in a Form -like container (like Map ).

Methods

toFormKey :: k -> Text Source #

Render a key for a Form .

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ToFormKey Bool Source #
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ToFormKey Char Source #
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ToFormKey Double Source #
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ToFormKey Float Source #
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ToFormKey Int Source #
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ToFormKey Int8 Source #
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ToFormKey Int16 Source #
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ToFormKey Int32 Source #
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ToFormKey Int64 Source #
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ToFormKey Integer Source #
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ToFormKey Natural Source #
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ToFormKey Ordering Source #
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ToFormKey Word Source #
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ToFormKey Word8 Source #
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ToFormKey Word16 Source #
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ToFormKey Word32 Source #
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ToFormKey Word64 Source #
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ToFormKey () Source #
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ToFormKey Text Source #
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ToFormKey Text Source #
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ToFormKey String Source #
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ToFormKey Void Source #
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ToFormKey All Source #
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ToFormKey Any Source #
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ToFormKey UTCTime Source #
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ToFormKey ZonedTime Source #
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ToFormKey LocalTime Source #
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ToFormKey NominalDiffTime Source #
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ToFormKey Day Source #
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ToFormKey QuarterOfYear Source #
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ToFormKey Quarter Source #
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ToFormKey Month Source #
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ToFormKey a => ToFormKey ( Min a) Source #
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ToFormKey a => ToFormKey ( Max a) Source #
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ToFormKey a => ToFormKey ( First a) Source #
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ToFormKey a => ToFormKey ( Last a) Source #
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ToFormKey a => ToFormKey ( Identity a) Source #

Since: 0.4.2

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ToFormKey a => ToFormKey ( Dual a) Source #
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ToFormKey a => ToFormKey ( Sum a) Source #
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ToFormKey a => ToFormKey ( Product a) Source #
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ToFormKey a => ToFormKey ( Const a b) Source #

Since: 0.4.2

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ToFormKey a => ToFormKey ( Tagged b a) Source #
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class FromFormKey k where Source #

Typeclass for types that can be parsed from keys of a Form . This is the reverse of ToFormKey .

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FromFormKey Bool Source #
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FromFormKey Char Source #
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FromFormKey Double Source #
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FromFormKey Float Source #
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FromFormKey Int Source #
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FromFormKey Int8 Source #
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FromFormKey Int16 Source #
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FromFormKey Int32 Source #
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FromFormKey Int64 Source #
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FromFormKey Integer Source #
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FromFormKey Natural Source #
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FromFormKey Ordering Source #
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FromFormKey Word Source #
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FromFormKey Word8 Source #
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FromFormKey Word16 Source #
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FromFormKey Word32 Source #
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FromFormKey Word64 Source #
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FromFormKey () Source #
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FromFormKey Text Source #
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FromFormKey Text Source #
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FromFormKey String Source #
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FromFormKey Void Source #
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FromFormKey All Source #
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FromFormKey Any Source #
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FromFormKey UTCTime Source #
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FromFormKey ZonedTime Source #
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FromFormKey LocalTime Source #
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FromFormKey NominalDiffTime Source #
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FromFormKey Day Source #
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FromFormKey QuarterOfYear Source #
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FromFormKey Quarter Source #
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FromFormKey Month Source #
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FromFormKey a => FromFormKey ( Min a) Source #
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FromFormKey a => FromFormKey ( Max a) Source #
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FromFormKey a => FromFormKey ( First a) Source #
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FromFormKey a => FromFormKey ( Last a) Source #
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FromFormKey a => FromFormKey ( Identity a) Source #

Since: 0.4.2

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FromFormKey a => FromFormKey ( Dual a) Source #
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FromFormKey a => FromFormKey ( Sum a) Source #
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FromFormKey a => FromFormKey ( Product a) Source #
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FromFormKey a => FromFormKey ( Const a b) Source #

Since: 0.4.2

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FromFormKey a => FromFormKey ( Tagged b a) Source #
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newtype Form Source #

The contents of a form, not yet URL-encoded.

Form can be URL-encoded with urlEncodeForm and URL-decoded with urlDecodeForm .

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IsList Form Source #

_NOTE:_ toList is unstable and may result in different key order (but not values). For a stable conversion use toListStable .

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Associated Types

type Item Form Source #

Eq Form Source #
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Read Form Source #
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Show Form Source #
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Generic Form Source #
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Associated Types

type Rep Form :: Type -> Type Source #

Semigroup Form Source #
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Monoid Form Source #
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FromForm Form Source #
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ToForm Form Source #
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type Rep Form Source #
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type Rep Form = D1 (' MetaData "Form" "Web.Internal.FormUrlEncoded" "http-api-data-0.5-14oLdRuKzW0JKEB7XBM0aq" ' True ) ( C1 (' MetaCons "Form" ' PrefixI ' True ) ( S1 (' MetaSel (' Just "unForm") ' NoSourceUnpackedness ' NoSourceStrictness ' DecidedLazy ) ( Rec0 ( HashMap Text [ Text ]))))
type Item Form Source #
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class ToForm a where Source #

Convert a value into Form .

An example type and instance:

{-# LANGUAGE OverloadedLists #-}

data Person = Person
  { name :: String
  , age  :: Int }

instance ToForm Person where
  toForm person =
    [ ("name", toQueryParam (name person))
    , ("age", toQueryParam (age person)) ]

Instead of manually writing ToForm instances you can use a default generic implementation of toForm .

To do that, simply add deriving Generic clause to your datatype and declare a ToForm instance for your datatype without giving definition for toForm .

For instance, the previous example can be simplified into this:

data Person = Person
  { name :: String
  , age  :: Int
  } deriving (Generic)

instance ToForm Person

The default implementation of toForm is genericToForm .

Minimal complete definition

Nothing

Methods

toForm :: a -> Form Source #

Convert a value into Form .

fromEntriesByKey :: ( ToFormKey k, ToHttpApiData v) => [(k, [v])] -> Form Source #

Convert a list of entries groupped by key into a Form .

>>> fromEntriesByKey [("name",["Nick"]),("color",["red","blue"])]
fromList [("color","red"),("color","blue"),("name","Nick")]

data Proxy3 a b c Source #

Constructors

Proxy3

type family NotSupported (cls :: k1) (a :: k2) (reason :: Symbol ) :: Constraint where ... Source #

Equations

NotSupported cls a reason = TypeError (((((((' Text "Cannot derive a Generic-based " :<>: ' ShowType cls) :<>: ' Text " instance for ") :<>: ' ShowType a) :<>: ' Text ".") :$$: (((' ShowType a :<>: ' Text " ") :<>: ' Text reason) :<>: ' Text ",")) :$$: ((' Text "but Generic-based " :<>: ' ShowType cls) :<>: ' Text " instances can be derived only for records")) :$$: ' Text "(i.e. product types with named fields).")

genericToForm :: forall a. ( Generic a, GToForm a ( Rep a)) => FormOptions -> a -> Form Source #

A Generic -based implementation of toForm . This is used as a default implementation in ToForm .

Note that this only works for records (i.e. product data types with named fields):

data Person = Person
  { name :: String
  , age  :: Int
  } deriving (Generic)

In this implementation each field's value gets encoded using toQueryParam . Two field types are exceptions:

  • for values of type Maybe a an entry is added to the Form only when it is Just x and the encoded value is toQueryParam x ; Nothing values are omitted from the Form ;
  • for values of type [a] (except [ Char ] ) an entry is added for every item in the list; if the list is empty no entries are added to the Form ;

Here's an example:

data Post = Post
  { title    :: String
  , subtitle :: Maybe String
  , comments :: [String]
  } deriving (Generic, Show)

instance ToForm Post
>>> urlEncodeAsFormStable Post { title = "Test", subtitle = Nothing, comments = ["Nice post!", "+1"] }
"comments=Nice%20post%21&comments=%2B1&title=Test"

class GToForm t (f :: * -> *) where Source #

Instances

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( GToForm t f, GToForm t g) => GToForm (t :: k) (f :*: g) Source #
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NotSupported ToForm t "is a sum type" => GToForm (t :: k) (f :+: g) Source #
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Selector s => GToForm (t :: k) ( M1 S s ( K1 i String :: Type -> Type )) Source #
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( Selector s, ToHttpApiData c) => GToForm (t :: k) ( M1 S s ( K1 i [c] :: Type -> Type )) Source #
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( Selector s, ToHttpApiData c) => GToForm (t :: k) ( M1 S s ( K1 i ( Maybe c) :: Type -> Type )) Source #
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( Selector s, ToHttpApiData c) => GToForm (t :: k) ( M1 S s ( K1 i c :: Type -> Type )) Source #
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GToForm t f => GToForm (t :: k) ( M1 C x f) Source #
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GToForm t f => GToForm (t :: k) ( M1 D x f) Source #
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class FromForm a where Source #

Parse Form into a value.

An example type and instance:

data Person = Person
  { name :: String
  , age  :: Int }

instance FromForm Person where
  fromForm f = Person
    <$> parseUnique "name" f
    <*> parseUnique "age"  f

Instead of manually writing FromForm instances you can use a default generic implementation of fromForm .

To do that, simply add deriving Generic clause to your datatype and declare a FromForm instance for your datatype without giving definition for fromForm .

For instance, the previous example can be simplified into this:

data Person = Person
  { name :: String
  , age  :: Int
  } deriving (Generic)

instance FromForm Person

The default implementation of fromForm is genericFromForm . It only works for records and it will use parseQueryParam for each field's value.

Minimal complete definition

Nothing

toEntriesByKey :: ( FromFormKey k, FromHttpApiData v) => Form -> Either Text [(k, [v])] Source #

Parse a Form into a list of entries groupped by key.

_NOTE:_ this conversion is unstable and may result in different key order (but not values). For a stable encoding see toEntriesByKeyStable .

toEntriesByKeyStable :: ( Ord k, FromFormKey k, FromHttpApiData v) => Form -> Either Text [(k, [v])] Source #

Parse a Form into a list of entries groupped by key.

>>> toEntriesByKeyStable [("name", "Nick"), ("color", "red"), ("color", "white")] :: Either Text [(Text, [Text])]
Right [("color",["red","white"]),("name",["Nick"])]

For an unstable (but faster) conversion see toEntriesByKey .

genericFromForm :: forall a. ( Generic a, GFromForm a ( Rep a)) => FormOptions -> Form -> Either Text a Source #

A Generic -based implementation of fromForm . This is used as a default implementation in FromForm .

Note that this only works for records (i.e. product data types with named fields):

data Person = Person
  { name :: String
  , age  :: Int
  } deriving (Generic)

In this implementation each field's value gets decoded using parseQueryParam . Two field types are exceptions:

  • for values of type Maybe a an entry is parsed if present in the Form and the is decoded with parseQueryParam ; if no entry is present result is Nothing ;
  • for values of type [a] (except [ Char ] ) all entries are parsed to produce a list of parsed values;

Here's an example:

data Post = Post
  { title    :: String
  , subtitle :: Maybe String
  , comments :: [String]
  } deriving (Generic, Show)

instance FromForm Post
>>> urlDecodeAsForm "comments=Nice%20post%21&comments=%2B1&title=Test" :: Either Text Post
Right (Post {title = "Test", subtitle = Nothing, comments = ["Nice post!","+1"]})

class GFromForm t (f :: * -> *) where Source #

Instances

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( GFromForm t f, GFromForm t g) => GFromForm (t :: k) (f :*: g) Source #
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NotSupported FromForm t "is a sum type" => GFromForm (t :: k) (f :+: g) Source #
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Selector s => GFromForm (t :: k) ( M1 S s ( K1 i String :: Type -> Type )) Source #
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( Selector s, FromHttpApiData c) => GFromForm (t :: k) ( M1 S s ( K1 i [c] :: Type -> Type )) Source #
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( Selector s, FromHttpApiData c) => GFromForm (t :: k) ( M1 S s ( K1 i ( Maybe c) :: Type -> Type )) Source #
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( Selector s, FromHttpApiData c) => GFromForm (t :: k) ( M1 S s ( K1 i c :: Type -> Type )) Source #
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GFromForm t f => GFromForm (t :: k) ( M1 C x f) Source #
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GFromForm t f => GFromForm (t :: k) ( M1 D x f) Source #
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urlEncodeForm :: Form -> ByteString Source #

Encode a Form to an application/x-www-form-urlencoded ByteString .

_NOTE:_ this encoding is unstable and may result in different key order (but not values). For a stable encoding see urlEncodeFormStable .

urlEncodeFormStable :: Form -> ByteString Source #

Encode a Form to an application/x-www-form-urlencoded ByteString .

For an unstable (but faster) encoding see urlEncodeForm .

Key-value pairs get encoded to key=value and separated by & :

>>> urlEncodeFormStable [("name", "Julian"), ("lastname", "Arni")]
"lastname=Arni&name=Julian"

Keys with empty values get encoded to just key (without the = sign):

>>> urlEncodeFormStable [("is_test", "")]
"is_test"

Empty keys are allowed too:

>>> urlEncodeFormStable [("", "foobar")]
"=foobar"

However, if both key and value are empty, the key-value pair is ignored. (This prevents urlDecodeForm . urlEncodeFormStable from being a true isomorphism).

>>> urlEncodeFormStable [("", "")]
""

Everything is escaped with escapeURIString isUnreserved :

>>> urlEncodeFormStable [("fullname", "Andres Löh")]
"fullname=Andres%20L%C3%B6h"

urlEncodeParams :: [( Text , Text )] -> ByteString Source #

Encode a list of key-value pairs to an application/x-www-form-urlencoded ByteString .

See also urlEncodeFormStable .

urlDecodeForm :: ByteString -> Either Text Form Source #

Decode an application/x-www-form-urlencoded ByteString to a Form .

Key-value pairs get decoded normally:

>>> urlDecodeForm "name=Greg&lastname=Weber"
Right (fromList [("lastname","Weber"),("name","Greg")])

Keys with no values get decoded to pairs with empty values.

>>> urlDecodeForm "is_test"
Right (fromList [("is_test","")])

Empty keys are allowed:

>>> urlDecodeForm "=foobar"
Right (fromList [("","foobar")])

The empty string gets decoded into an empty Form :

>>> urlDecodeForm ""
Right (fromList [])

Everything is un-escaped with unEscapeString :

>>> urlDecodeForm "fullname=Andres%20L%C3%B6h"
Right (fromList [("fullname","Andres L\246h")])

Improperly formed strings result in an error:

>>> urlDecodeForm "this=has=too=many=equals"
Left "not a valid pair: this=has=too=many=equals"

urlDecodeParams :: ByteString -> Either Text [( Text , Text )] Source #

Decode an application/x-www-form-urlencoded ByteString to a list of key-value pairs.

See also urlDecodeForm .

urlDecodeAsForm :: FromForm a => ByteString -> Either Text a Source #

This is a convenience function for decoding a application/x-www-form-urlencoded ByteString directly to a datatype that has an instance of FromForm .

This is effectively fromForm <=< urlDecodeForm .

>>> urlDecodeAsForm "name=Dennis&age=22" :: Either Text Person
Right (Person {name = "Dennis", age = 22})

urlEncodeAsForm :: ToForm a => a -> ByteString Source #

This is a convenience function for encoding a datatype that has instance of ToForm directly to a application/x-www-form-urlencoded ByteString .

This is effectively urlEncodeForm . toForm .

_NOTE:_ this encoding is unstable and may result in different key order (but not values). For a stable encoding see urlEncodeAsFormStable .

urlEncodeAsFormStable :: ToForm a => a -> ByteString Source #

This is a convenience function for encoding a datatype that has instance of ToForm directly to a application/x-www-form-urlencoded ByteString .

This is effectively urlEncodeFormStable . toForm .

>>> urlEncodeAsFormStable Person {name = "Dennis", age = 22}
"age=22&name=Dennis"

lookupAll :: Text -> Form -> [ Text ] Source #

Find all values corresponding to a given key in a Form .

>>> lookupAll "name" []
[]
>>> lookupAll "name" [("name", "Oleg")]
["Oleg"]
>>> lookupAll "name" [("name", "Oleg"), ("name", "David")]
["Oleg","David"]

lookupMaybe :: Text -> Form -> Either Text ( Maybe Text ) Source #

Lookup an optional value for a key. Fail if there is more than one value.

>>> lookupMaybe "name" []
Right Nothing
>>> lookupMaybe "name" [("name", "Oleg")]
Right (Just "Oleg")
>>> lookupMaybe "name" [("name", "Oleg"), ("name", "David")]
Left "Duplicate key \"name\""

lookupUnique :: Text -> Form -> Either Text Text Source #

Lookup a unique value for a key. Fail if there is zero or more than one value.

>>> lookupUnique "name" []
Left "Could not find key \"name\""
>>> lookupUnique "name" [("name", "Oleg")]
Right "Oleg"
>>> lookupUnique "name" [("name", "Oleg"), ("name", "David")]
Left "Duplicate key \"name\""

parseAll :: FromHttpApiData v => Text -> Form -> Either Text [v] Source #

Lookup all values for a given key in a Form and parse them with parseQueryParams .

>>> parseAll "age" [] :: Either Text [Word8]
Right []
>>> parseAll "age" [("age", "8"), ("age", "seven")] :: Either Text [Word8]
Left "could not parse: `seven' (input does not start with a digit)"
>>> parseAll "age" [("age", "8"), ("age", "777")] :: Either Text [Word8]
Left "out of bounds: `777' (should be between 0 and 255)"
>>> parseAll "age" [("age", "12"), ("age", "25")] :: Either Text [Word8]
Right [12,25]

parseMaybe :: FromHttpApiData v => Text -> Form -> Either Text ( Maybe v) Source #

Lookup an optional value for a given key and parse it with parseQueryParam . Fail if there is more than one value for the key.

>>> parseMaybe "age" [] :: Either Text (Maybe Word8)
Right Nothing
>>> parseMaybe "age" [("age", "12"), ("age", "25")] :: Either Text (Maybe Word8)
Left "Duplicate key \"age\""
>>> parseMaybe "age" [("age", "seven")] :: Either Text (Maybe Word8)
Left "could not parse: `seven' (input does not start with a digit)"
>>> parseMaybe "age" [("age", "777")] :: Either Text (Maybe Word8)
Left "out of bounds: `777' (should be between 0 and 255)"
>>> parseMaybe "age" [("age", "7")] :: Either Text (Maybe Word8)
Right (Just 7)

parseUnique :: FromHttpApiData v => Text -> Form -> Either Text v Source #

Lookup a unique value for a given key and parse it with parseQueryParam . Fail if there is zero or more than one value for the key.

>>> parseUnique "age" [] :: Either Text Word8
Left "Could not find key \"age\""
>>> parseUnique "age" [("age", "12"), ("age", "25")] :: Either Text Word8
Left "Duplicate key \"age\""
>>> parseUnique "age" [("age", "seven")] :: Either Text Word8
Left "could not parse: `seven' (input does not start with a digit)"
>>> parseUnique "age" [("age", "777")] :: Either Text Word8
Left "out of bounds: `777' (should be between 0 and 255)"
>>> parseUnique "age" [("age", "7")] :: Either Text Word8
Right 7

data FormOptions Source #

Generic -based deriving options for ToForm and FromForm .

A common use case for non-default FormOptions is to strip a prefix off of field labels:

data Project = Project
  { projectName :: String
  , projectSize :: Int
  } deriving (Generic, Show)

myOptions :: FormOptions
myOptions = FormOptions
 { fieldLabelModifier = map toLower . drop (length "project") }

instance ToForm Project where
  toForm = genericToForm myOptions

instance FromForm Project where
  fromForm = genericFromForm myOptions
>>> urlEncodeAsFormStable Project { projectName = "http-api-data", projectSize = 172 }
"name=http-api-data&size=172"
>>> urlDecodeAsForm "name=http-api-data&size=172" :: Either Text Project
Right (Project {projectName = "http-api-data", projectSize = 172})

Constructors

FormOptions

Fields

sortOn :: Ord b => (a -> b) -> [a] -> [a] Source #