287 lines
7.9 KiB
Haskell
287 lines
7.9 KiB
Haskell
{-# LANGUAGE CPP #-}
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{-# LANGUAGE ConstraintKinds #-}
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{-# LANGUAGE DataKinds #-}
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{-# LANGUAGE FlexibleContexts #-}
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{-# LANGUAGE FlexibleInstances #-}
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#if !MIN_VERSION_base(4,8,0)
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{-# LANGUAGE NullaryTypeClasses #-}
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#endif
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{-# LANGUAGE MultiParamTypeClasses #-}
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{-# LANGUAGE ScopedTypeVariables #-}
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{-# LANGUAGE TemplateHaskell #-}
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{-# LANGUAGE TypeFamilies #-}
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{-# LANGUAGE TypeOperators #-}
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{-# LANGUAGE UndecidableInstances #-}
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{-# LANGUAGE OverloadedStrings #-}
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-- | Generalizes all the data needed to make code generation work with
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-- arbitrary programming languages.
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module Servant.Foreign
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( HasForeign(..)
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, Segment(..)
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, SegmentType(..)
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, FunctionName
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, QueryArg(..)
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, HeaderArg(..)
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, ArgType(..)
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, Req
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, captureArg
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, defReq
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, concatCase
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, snakeCase
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, camelCase
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-- lenses
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, argType
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, argName
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, isCapture
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, funcName
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, path
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, reqUrl
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, reqBody
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, reqHeaders
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, reqMethod
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, segment
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, queryStr
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-- re-exports
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, module Servant.API
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) where
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import Control.Lens (makeLenses, (%~), (&), (.~), (<>~))
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import Data.Proxy
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import Data.Text
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import GHC.Exts (Constraint)
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import GHC.TypeLits
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import Prelude hiding (concat)
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import Servant.API
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-- | Function name builder that simply concat each part together
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concatCase :: FunctionName -> Text
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concatCase = concat
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-- | Function name builder using the snake_case convention.
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-- each part is separated by a single underscore character.
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snakeCase :: FunctionName -> Text
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snakeCase = intercalate "_"
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-- | Function name builder using the CamelCase convention.
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-- each part begins with an upper case character.
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camelCase :: FunctionName -> Text
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camelCase [] = ""
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camelCase (p:ps) = concat $ p : camelCase' ps
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where camelCase' [] = []
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camelCase' (r:rs) = toUpper r : camelCase' rs
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type Arg = Text
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newtype Segment = Segment { _segment :: SegmentType }
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deriving (Eq, Show)
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data SegmentType = Static Text -- ^ a static path segment. like "/foo"
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| Cap Arg -- ^ a capture. like "/:userid"
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deriving (Eq, Show)
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type Path = [Segment]
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data ArgType =
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Normal
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| Flag
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| List
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deriving (Eq, Show)
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data QueryArg = QueryArg
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{ _argName :: Arg
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, _argType :: ArgType
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} deriving (Eq, Show)
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data HeaderArg = HeaderArg
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{ headerArgName :: Text
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}
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| ReplaceHeaderArg
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{ headerArgName :: Text
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, headerPattern :: Text
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} deriving (Eq, Show)
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data Url = Url
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{ _path :: Path
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, _queryStr :: [QueryArg]
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} deriving (Eq, Show)
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defUrl :: Url
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defUrl = Url [] []
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type FunctionName = [Text]
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type Method = Text
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data Req = Req
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{ _reqUrl :: Url
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, _reqMethod :: Method
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, _reqHeaders :: [HeaderArg]
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, _reqBody :: Bool
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, _funcName :: FunctionName
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} deriving (Eq, Show)
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makeLenses ''QueryArg
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makeLenses ''Segment
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makeLenses ''Url
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makeLenses ''Req
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isCapture :: Segment -> Bool
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isCapture (Segment (Cap _)) = True
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isCapture _ = False
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captureArg :: Segment -> Arg
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captureArg (Segment (Cap s)) = s
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captureArg _ = error "captureArg called on non capture"
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defReq :: Req
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defReq = Req defUrl "GET" [] False []
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-- | To be used exclusively as a "negative" return type/constraint
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-- by @'Elem`@ type family.
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class NotFound
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type family Elem (a :: *) (ls::[*]) :: Constraint where
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Elem a '[] = NotFound
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Elem a (a ': list) = ()
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Elem a (b ': list) = Elem a list
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class HasForeign (layout :: *) where
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type Foreign layout :: *
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foreignFor :: Proxy layout -> Req -> Foreign layout
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instance (HasForeign a, HasForeign b)
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=> HasForeign (a :<|> b) where
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type Foreign (a :<|> b) = Foreign a :<|> Foreign b
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foreignFor Proxy req =
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foreignFor (Proxy :: Proxy a) req
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:<|> foreignFor (Proxy :: Proxy b) req
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instance (KnownSymbol sym, HasForeign sublayout)
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=> HasForeign (Capture sym a :> sublayout) where
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type Foreign (Capture sym a :> sublayout) = Foreign sublayout
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foreignFor Proxy req =
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foreignFor (Proxy :: Proxy sublayout) $
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req & reqUrl.path <>~ [Segment (Cap str)]
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& funcName %~ (++ ["by", str])
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where str = pack . symbolVal $ (Proxy :: Proxy sym)
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instance Elem JSON list => HasForeign (Delete list a) where
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type Foreign (Delete list a) = Req
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foreignFor Proxy req =
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req & funcName %~ ("delete" :)
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& reqMethod .~ "DELETE"
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instance Elem JSON list => HasForeign (Get list a) where
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type Foreign (Get list a) = Req
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foreignFor Proxy req =
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req & funcName %~ ("get" :)
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& reqMethod .~ "GET"
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instance (KnownSymbol sym, HasForeign sublayout)
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=> HasForeign (Header sym a :> sublayout) where
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type Foreign (Header sym a :> sublayout) = Foreign sublayout
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foreignFor Proxy req =
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foreignFor subP (req & reqHeaders <>~ [HeaderArg hname])
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where hname = pack . symbolVal $ (Proxy :: Proxy sym)
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subP = Proxy :: Proxy sublayout
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instance Elem JSON list => HasForeign (Post list a) where
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type Foreign (Post list a) = Req
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foreignFor Proxy req =
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req & funcName %~ ("post" :)
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& reqMethod .~ "POST"
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instance Elem JSON list => HasForeign (Put list a) where
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type Foreign (Put list a) = Req
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foreignFor Proxy req =
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req & funcName %~ ("put" :)
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& reqMethod .~ "PUT"
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instance (KnownSymbol sym, HasForeign sublayout)
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=> HasForeign (QueryParam sym a :> sublayout) where
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type Foreign (QueryParam sym a :> sublayout) = Foreign sublayout
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foreignFor Proxy req =
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foreignFor (Proxy :: Proxy sublayout) $
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req & reqUrl.queryStr <>~ [QueryArg str Normal]
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where str = pack . symbolVal $ (Proxy :: Proxy sym)
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instance (KnownSymbol sym, HasForeign sublayout)
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=> HasForeign (QueryParams sym a :> sublayout) where
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type Foreign (QueryParams sym a :> sublayout) = Foreign sublayout
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foreignFor Proxy req =
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foreignFor (Proxy :: Proxy sublayout) $
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req & reqUrl.queryStr <>~ [QueryArg str List]
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where str = pack . symbolVal $ (Proxy :: Proxy sym)
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instance (KnownSymbol sym, HasForeign sublayout)
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=> HasForeign (QueryFlag sym :> sublayout) where
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type Foreign (QueryFlag sym :> sublayout) = Foreign sublayout
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foreignFor Proxy req =
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foreignFor (Proxy :: Proxy sublayout) $
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req & reqUrl.queryStr <>~ [QueryArg str Flag]
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where str = pack . symbolVal $ (Proxy :: Proxy sym)
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instance HasForeign Raw where
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type Foreign Raw = Method -> Req
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foreignFor Proxy req method =
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req & funcName %~ ((toLower method) :)
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& reqMethod .~ method
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instance (Elem JSON list, HasForeign sublayout) => HasForeign (ReqBody list a :> sublayout) where
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type Foreign (ReqBody list a :> sublayout) = Foreign sublayout
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foreignFor Proxy req =
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foreignFor (Proxy :: Proxy sublayout) $
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req & reqBody .~ True
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instance (KnownSymbol path, HasForeign sublayout)
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=> HasForeign (path :> sublayout) where
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type Foreign (path :> sublayout) = Foreign sublayout
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foreignFor Proxy req =
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foreignFor (Proxy :: Proxy sublayout) $
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req & reqUrl.path <>~ [Segment (Static str)]
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& funcName %~ (++ [str])
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where str = Data.Text.map (\c -> if c == '.' then '_' else c) . pack . symbolVal $ (Proxy :: Proxy path)
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instance HasForeign sublayout => HasForeign (RemoteHost :> sublayout) where
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type Foreign (RemoteHost :> sublayout) = Foreign sublayout
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foreignFor Proxy req =
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foreignFor (Proxy :: Proxy sublayout) req
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instance HasForeign sublayout => HasForeign (IsSecure :> sublayout) where
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type Foreign (IsSecure :> sublayout) = Foreign sublayout
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foreignFor Proxy req =
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foreignFor (Proxy :: Proxy sublayout) req
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instance HasForeign sublayout => HasForeign (Vault :> sublayout) where
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type Foreign (Vault :> sublayout) = Foreign sublayout
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foreignFor Proxy req =
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foreignFor (Proxy :: Proxy sublayout) req
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instance HasForeign sublayout => HasForeign (HttpVersion :> sublayout) where
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type Foreign (HttpVersion :> sublayout) = Foreign sublayout
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foreignFor Proxy req =
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foreignFor (Proxy :: Proxy sublayout) req
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