graphql-engine/server/src-lib/Hasura/Backends/Postgres/Translate/Column.hs

module Hasura.Backends.Postgres.Translate.Column
  ( toTxtValue
  , toJSONableExp
  ) where

import           Hasura.Prelude

import           Hasura.Backends.Postgres.SQL.DML
import           Hasura.Backends.Postgres.SQL.Types
import           Hasura.Backends.Postgres.SQL.Value
import           Hasura.Backends.Postgres.Types.Column
import           Hasura.RQL.Types.Column
import           Hasura.SQL.Backend


toTxtValue :: ColumnValue ('Postgres pgKind) -> SQLExp
toTxtValue ColumnValue{..} =
  withTyAnn ty . withConstructorFn ty $ txtEncoder cvValue
  where
    ty = unsafePGColumnToBackend cvType

-- | Formats each columns to appropriate SQL expression
toJSONableExp :: Bool -> ColumnType ('Postgres pgKind) -> Bool -> SQLExp -> SQLExp
toJSONableExp stringifyNum colType asText expression
  -- If its a numeric column greater than a 32-bit integer, we have to stringify it as JSON spec doesn't support >32-bit integers
  | asText || (isScalarColumnWhere isBigNum colType && stringifyNum) =
      expression `SETyAnn` textTypeAnn
  -- If the column is either a `Geometry` or `Geography` then apply the `ST_AsGeoJSON` function to convert it into GeoJSON format
  | isScalarColumnWhere isGeoType colType =
      SEFnApp "ST_AsGeoJSON"
      [ expression
      , SEUnsafe "15" -- max decimal digits
      , SEUnsafe "4"  -- to print out crs
      ] Nothing
      `SETyAnn` jsonTypeAnn
  | otherwise = expression