introduce type ReqBodyContentType replacing use of Bool

servant-foreign/src/Servant/Foreign.hs

@@ -5,6 +5,7 @@ module Servant.Foreign
   , HeaderArg(..)
   , QueryArg(..)
   , Req(..)
+  , ReqBodyContentType(..)
   , Segment(..)
   , SegmentType(..)
   , Url(..)
@@ -21,7 +22,7 @@ module Servant.Foreign
   , reqMethod
   , reqHeaders
   , reqBody
-  , reqBodyIsJSON
+  , reqBodyContentType
   , reqReturnType
   , reqFuncName
   , path

servant-foreign/src/Servant/Foreign/Internal.hs

@@ -123,6 +123,9 @@ defUrl = Url [] []
 
 makeLenses ''Url
 
+data ReqBodyContentType = ReqBodyJSON | ReqBodyMultipart
+  deriving (Data, Eq, Show, Read)
+
 data Req f = Req
   { _reqUrl             :: Url f
   , _reqMethod          :: HTTP.Method
@@ -130,14 +133,14 @@ data Req f = Req
   , _reqBody            :: Maybe f
   , _reqReturnType      :: Maybe f
   , _reqFuncName        :: FunctionName
-  , _reqBodyIsJSON :: Bool
+  , _reqBodyContentType :: ReqBodyContentType
   }
   deriving (Data, Eq, Show, Typeable)
 
 makeLenses ''Req
 
 defReq :: Req ftype
-defReq = Req defUrl "GET" [] Nothing Nothing (FunctionName []) True
+defReq = Req defUrl "GET" [] Nothing Nothing (FunctionName []) ReqBodyJSON
 
 -- | 'HasForeignType' maps Haskell types with types in the target
 -- language of your backend. For example, let's say you're