Simple library for building API wrappers in Haskell – define a Builder, add some types with Receivable instances, an error type, and some routes, and you can easily use any API from Haskell code. Based on a EitherT StateT StateT monad transformer stack.
Define a type for a stack overflow question:
data Question = Question { title :: Text , isAnswered :: Bool , score :: Int , tags :: [Text] } deriving (Show, Eq)And a wrapper since SO wraps its JSON responses:
newtype Questions = Questions [Question] deriving (Show, Eq)Add FromJSON instances for both the types:
instance FromJSON Question where parseJSON (Object o) = Question <$> o .: "title" <*> o .: "is_answered" <*> o .: "score" <*> o .: "tags" parseJSON _ = mempty instance FromJSON Questions where parseJSON (Object o) = Questions <$> o .: "items" parseJSON _ = memptyand a Receivable instance for Questions that just uses the FromJSON instance:
instance Receivable Questions where receive = useFromJSONDefine a Builder for the API endpoint:
stackOverflow :: Builder stackOverflow = basicBuilder "StackOverflow API" "http://api.stackexchange.com"And the Route to use to get the data:
answersRoute :: Route answersRoute = Route { urlPieces = [ "2.2", "questions" ] , urlParams = [ "order" =. Just "desc" , "sort" =. Just "activity" , "site" =. Just "stackoverflow" ] , httpMethod = GET }And a function to actually run the API:
getAnswers :: IO (Either (APIError ()) Questions) getAnswers = execAPI stackOverflow () $ runRoute answersRoute > getAnswers Right (Questions [Question {title = "Using parse API with codeigniter", isAnswered = True, score = 2, tags = ["php","codeigniter","parse.com","codeigniter-2","php-5.6"]},Question {title = "Object...