Add sample JSON API for listing challenges

Foundation.hs

@@ -152,6 +152,7 @@ instance Yesod App where
     isAuthorized QueryFormR _ = regularAuthorization
     isAuthorized (QueryResultsR _) _ = regularAuthorization
     isAuthorized ListChallengesR _ = regularAuthorization
+    isAuthorized ListChallengesJsonR _ = regularAuthorization
     isAuthorized (ViewVariantR _ ) _ = regularAuthorization
     isAuthorized (ViewVariantTestR _ _) _ = regularAuthorization
 

Handler/ListChallenges.hs

@@ -2,12 +2,30 @@ module Handler.ListChallenges where
 
 import Import
 
+mainCondition :: [Filter Challenge]
+mainCondition = [ChallengeArchived !=. Just True]
+
 getListChallengesR :: Handler Html
-getListChallengesR = generalListChallenges [ChallengeArchived !=. Just True]
+getListChallengesR = generalListChallenges mainCondition
+
+getListChallengesJsonR :: Handler Value
+getListChallengesJsonR = generalListChallengesJson mainCondition
 
 getListArchivedChallengesR :: Handler Html
 getListArchivedChallengesR = generalListChallenges [ChallengeArchived ==. Just True]
 
+instance ToJSON (Entity Challenge) where
+    toJSON (Entity _ ch) = object
+        [ "link"  .= ("/challenge/" <> (challengeName ch))
+        , "title" .= challengeTitle ch
+        , "description" .= challengeDescription ch
+        ]
+
+generalListChallengesJson :: [Filter Challenge] -> Handler Value
+generalListChallengesJson filterExpr = do
+  challenges <- getChallenges filterExpr
+  return $ toJSON challenges
+
 generalListChallenges :: [Filter Challenge] -> Handler Html
 generalListChallenges filterExpr = do
   challenges <- getChallenges filterExpr

config/routes

@@ -10,6 +10,7 @@
 /view-progress/#Int ViewProgressR GET
 /open-view-progress/#Int OpenViewProgressR GET
 /list-challenges ListChallengesR GET
+/api/list-challenges ListChallengesJsonR GET
 /list-archived-challenges ListArchivedChallengesR GET
 /challenge-image/#ChallengeId ChallengeImageR GET