Servant.API.Modifiers

Required / optional argument

data Required

Required argument. Not wrapped.

data Optional

Optional argument. Wrapped in Maybe.

Instances

(KnownSymbol h, ToHttpApiData v) => AddHeader h v (Headers ((:) * fst rest) a) (Headers ((:) * (Header * h v) ((:) * fst rest)) a)

Methods

addOptionalHeader :: ResponseHeader h v -> Headers ((* ': fst) rest) a -> Headers ((* ': Header * h v) ((* ': fst) rest)) a

(FromHttpApiData v, BuildHeadersTo xs, KnownSymbol h) => BuildHeadersTo ((:) * (Header * h v) xs)

Methods

buildHeadersTo :: [Header] -> HList ((* ': Header * h v) xs)

type FoldRequired mods = FoldRequired' False mods

Fold modifier list to decide whether argument is required.

>>> :kind! FoldRequired '[Required, Description "something"]
FoldRequired '[Required, Description "something"] :: Bool
= 'True

>>> :kind! FoldRequired '[Required, Optional]
FoldRequired '[Required, Optional] :: Bool
= 'False

>>> :kind! FoldRequired '[]
FoldRequired '[] :: Bool
= 'False

type family FoldRequired' (acc :: Bool) (mods :: [*]) :: Bool where ...

Implementation of FoldRequired.

Equations

FoldRequired' acc '[] = acc

FoldRequired' acc (Required ': mods) = FoldRequired' True mods

FoldRequired' acc (Optional ': mods) = FoldRequired' False mods

FoldRequired' acc (mod ': mods) = FoldRequired' acc mods

Lenient / strict parsing

data Lenient

Leniently parsed argument, i.e. parsing never fail. Wrapped in Either Text.

data Strict

Strictly parsed argument. Not wrapped.

Instances

(KnownSymbol h, ToHttpApiData v) => AddHeader h v (Headers ((:) * fst rest) a) (Headers ((:) * (Header * h v) ((:) * fst rest)) a)

Methods

addOptionalHeader :: ResponseHeader h v -> Headers ((* ': fst) rest) a -> Headers ((* ': Header * h v) ((* ': fst) rest)) a

(FromHttpApiData v, BuildHeadersTo xs, KnownSymbol h) => BuildHeadersTo ((:) * (Header * h v) xs)

Methods

buildHeadersTo :: [Header] -> HList ((* ': Header * h v) xs)

type FoldLenient mods = FoldLenient' False mods

Fold modifier list to decide whether argument should be parsed strictly or leniently.

>>> :kind! FoldLenient '[]
FoldLenient '[] :: Bool
= 'False

type family FoldLenient' (acc :: Bool) (mods :: [*]) :: Bool where ...

Implementation of FoldLenient.

Equations

FoldLenient' acc '[] = acc

FoldLenient' acc (Lenient ': mods) = FoldLenient' True mods

FoldLenient' acc (Strict ': mods) = FoldLenient' False mods

FoldLenient' acc (mod ': mods) = FoldLenient' acc mods

Utilities

type RequiredArgument mods a = If (FoldRequired mods) a (Maybe a)

Helper type alias.

• Required ↦ a
• Optional ↦ Maybe a

foldRequiredArgument

Arguments

:: SBoolI (FoldRequired mods)

=> Proxy mods

-> (a -> r)

Required

-> (Maybe a -> r)

Optional

-> RequiredArgument mods a

-> r

Fold a RequiredAgument into a value

unfoldRequiredArgument

Arguments

:: (Monad m, SBoolI (FoldRequired mods), SBoolI (FoldLenient mods))

=> Proxy mods

-> m (RequiredArgument mods a)

error when argument is required

-> (Text -> m (RequiredArgument mods a))

error when argument is strictly parsed

-> Maybe (Either Text a)

value

-> m (RequiredArgument mods a)

Unfold a value into a RequiredArgument.

type RequestArgument mods a = If (FoldRequired mods) (If (FoldLenient mods) (Either Text a) a) (Maybe (If (FoldLenient mods) (Either Text a) a))

Helper type alias.

By default argument is Optional and Strict.

• Required, Strict ↦ a
• Required, Lenient ↦ Either Text a
• Optional, Strict ↦ Maybe a
• Optional, Lenient ↦ Maybe (Either Text a)

unfoldRequestArgument

Arguments

:: (Monad m, SBoolI (FoldRequired mods), SBoolI (FoldLenient mods))

=> Proxy mods

-> m (RequestArgument mods a)

error when argument is required

-> (Text -> m (RequestArgument mods a))

error when argument is strictly parsed

-> Maybe (Either Text a)

value

-> m (RequestArgument mods a)

Unfold a value into a RequestArgument.