module PostgREST.Error (PgError, errResponse) where
import qualified Hasql as H
import qualified Hasql.Postgres as P
import qualified Network.HTTP.Types.Status as HT
import qualified Data.Aeson as JSON
import qualified Data.Text as T
import Data.Aeson ((.=))
import Data.String.Conversions (cs)
import Data.String.Utils(replace)
import Network.Wai(Response, responseLBS)
import Network.HTTP.Types.Header
type PgError = H.SessionError P.Postgres
errResponse :: PgError -> Response
errResponse e = responseLBS (httpStatus e)
[(hContentType, "application/json")] (JSON.encode e)
instance JSON.ToJSON PgError where
toJSON (H.TxError (P.ErroneousResult c m d h)) = JSON.object [
"code" .= (cs c::T.Text),
"message" .= (cs m::T.Text),
"details" .= (fmap cs d::Maybe T.Text),
"hint" .= (fmap cs h::Maybe T.Text)]
toJSON (H.TxError (P.NoResult d)) = JSON.object [
"message" .= ("No response from server"::T.Text),
"details" .= (fmap cs d::Maybe T.Text)]
toJSON (H.TxError (P.UnexpectedResult m)) = JSON.object ["message" .= m]
toJSON (H.TxError P.NotInTransaction) = JSON.object [
"message" .= ("Not in transaction"::T.Text)]
toJSON (H.CxError (P.CantConnect d)) = JSON.object [
"message" .= ("Can't connect to the database"::T.Text),
"details" .= (fmap cs d::Maybe T.Text)]
toJSON (H.CxError (P.UnsupportedVersion v)) = JSON.object [
"message" .= ("Postgres version "++version++" is not supported") ]
where version = replace "0" "." (show v)
toJSON (H.ResultError m) = JSON.object ["message" .= m]
httpStatus :: PgError -> HT.Status
httpStatus (H.TxError (P.ErroneousResult codeBS _ _ _)) =
let code = cs codeBS in
case code of
'0':'8':_ -> HT.status503
'0':'9':_ -> HT.status500
'0':'L':_ -> HT.status403
'0':'P':_ -> HT.status403
'2':'5':_ -> HT.status500
'2':'8':_ -> HT.status403
'2':'D':_ -> HT.status500
'3':'8':_ -> HT.status500
'3':'9':_ -> HT.status500
'3':'B':_ -> HT.status500
'4':'0':_ -> HT.status500
'5':'3':_ -> HT.status503
'5':'4':_ -> HT.status413
'5':'5':_ -> HT.status500
'5':'7':_ -> HT.status500
'5':'8':_ -> HT.status500
'F':'0':_ -> HT.status500
'H':'V':_ -> HT.status500
'P':'0':_ -> HT.status500
'X':'X':_ -> HT.status500
"42P01" -> HT.status404
"42501" -> HT.status404
_ -> HT.status400
httpStatus (H.TxError (P.NoResult _)) = HT.status503
httpStatus _ = HT.status500