haskell - Return JSON based on Persistent Query from yesod handler -

haskell - Return JSON based on Persistent Query from yesod handler -

this additional question @konstantinerybnikov return json yesod handler.

what if want have persistent query selectlist , result info must homecoming json format? code it?

here code (adopt code of @konstantinerybnikov):

-- json import data.aeson (object, (.=)) import qualified data.aeson j import yesod.core.json (returnjson) getimagesr :: handler value getimagesr = images <- rundb $ selectlist [imagesfilename !=. ""] [desc imagesdate] homecoming $ object (if null images [] else [] -- want result of perstent in json format)

``

hope help me give thanks you.

i guess main problem selectlist returns list of entity record (where record type querying) instead of record, we'll have list of records using map entityval (entityval defined in entity). handler :

getimagesr = images <- rundb $ selectlist [imagesfilename !=. ""] [desc imagesdate] returnjson (map entityval images)

now it's matter of transforming [record] json. luckily, can done automatically adding word json persistent model definition (as shown here).

json haskell yesod