graphql-engine/server/src-lib/Hasura/RQL/DDL/Webhook/Transform/QueryParams.hs
jkachmar adb648b429 server: Rework internal webhook request transform components
## Description

Some of the documentation/organizational changes I was putting into the suggestions for #3624 were a bit too convoluted for GitHub's suggestion interface, so I'm putting them here instead.

PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3910
Co-authored-by: Solomon <24038+solomon-b@users.noreply.github.com>
GitOrigin-RevId: 06e0cb08bd18e7f8b21452df0697cfd80bc56fde
2022-03-23 20:24:44 +00:00

115 lines
4.4 KiB
Haskell

{-# LANGUAGE ApplicativeDo #-}
module Hasura.RQL.DDL.Webhook.Transform.QueryParams
( -- * Query transformations
QueryParams (..),
TransformFn (..),
QueryParamsTransformFn (..),
)
where
-------------------------------------------------------------------------------
import Data.Aeson (FromJSON, ToJSON)
import Data.Aeson qualified as J
import Data.HashMap.Strict qualified as M
import Data.Validation (Validation)
import Data.Validation qualified as V
import Hasura.Incremental (Cacheable)
import Hasura.Prelude
import Hasura.RQL.DDL.Webhook.Transform.Class
( RequestTransformCtx (..),
TemplatingEngine,
Transform (..),
TransformErrorBundle (..),
UnescapedTemplate (..),
runUnescapedRequestTemplateTransform',
validateRequestUnescapedTemplateTransform',
)
import Network.HTTP.Client.Transformable qualified as HTTP
-------------------------------------------------------------------------------
-- | The actual query params we are transforming.
--
-- This newtype is necessary because otherwise we end up with an
-- orphan instance.
newtype QueryParams = QueryParams {unQueryParams :: HTTP.Query}
instance Transform QueryParams where
-- NOTE: GHC does not let us attach Haddock documentation to data family
-- instances, so 'QueryParamsTransformFn' is defined separately from this
-- wrapper.
newtype TransformFn QueryParams
= QueryParamsTransformFn_ QueryParamsTransformFn
deriving stock (Show, Eq, Generic)
deriving newtype (NFData, Cacheable, FromJSON, ToJSON)
-- NOTE: GHC does not let us attach Haddock documentation to typeclass
-- method implementations, so 'applyQueryParamsTransformFn' is defined
-- separately.
transform (QueryParamsTransformFn_ fn) = applyQueryParamsTransformFn fn
-- NOTE: GHC does not let us attach Haddock documentation to typeclass
-- method implementations, so 'validateQueryParamsTransformFn' is defined
-- separately.
validate engine (QueryParamsTransformFn_ fn) =
validateQueryParamsTransformFn engine fn
-- | The defunctionalized transformation 'QueryParams'
newtype QueryParamsTransformFn
= AddOrReplace [(UnescapedTemplate, Maybe UnescapedTemplate)]
deriving stock (Eq, Generic, Show)
deriving newtype (Cacheable, NFData)
-- | Provide an implementation for the transformations defined by
-- 'QueryParamsTransformFn'.
--
-- If one views 'QueryParamsTransformFn' as an interface describing HTTP method
-- transformations, this can be seen as an implementation of these
-- transformations as normal Haskell functions.
applyQueryParamsTransformFn ::
MonadError TransformErrorBundle m =>
QueryParamsTransformFn ->
RequestTransformCtx ->
QueryParams ->
m QueryParams
applyQueryParamsTransformFn fn context _oldQueryParams = case fn of
AddOrReplace addOrReplaceParams -> do
-- NOTE: We use `ApplicativeDo` here to take advantage of Validation's
-- applicative sequencing
queryParams <- liftEither . V.toEither $
for addOrReplaceParams \(rawKey, rawValue) -> do
key <- runUnescapedRequestTemplateTransform' context rawKey
value <- traverse (runUnescapedRequestTemplateTransform' context) rawValue
pure (key, value)
pure $ QueryParams queryParams
-- | Validate that the provided 'QueryParamsTransformFn' is correct in the
-- context of a particular 'TemplatingEngine'.
--
-- This is a product of the fact that the correctness of a given transformation
-- may be dependent on zero, one, or more of the templated transformations
-- encoded within the given 'QueryParamsTransformFn'.
validateQueryParamsTransformFn ::
TemplatingEngine ->
QueryParamsTransformFn ->
Validation TransformErrorBundle ()
validateQueryParamsTransformFn engine = \case
AddOrReplace addOrReplaceParams ->
-- NOTE: We use `ApplicativeDo` here to take advantage of
-- Validation's applicative sequencing
for_ addOrReplaceParams \(key, val) -> do
validateRequestUnescapedTemplateTransform' engine key
traverse_ (validateRequestUnescapedTemplateTransform' engine) val
-- NOTE: There's a bug in `ApplicativeDo` which infers a `Monad`
-- constraint on this block if it doens't end with `pure ()`
pure ()
{-# ANN validateQueryParamsTransformFn ("HLint: ignore Redundant pure" :: String) #-}
instance J.ToJSON QueryParamsTransformFn where
toJSON (AddOrReplace addOrReplace) = J.toJSON $ M.fromList addOrReplace
instance J.FromJSON QueryParamsTransformFn where
parseJSON v = AddOrReplace . M.toList <$> J.parseJSON v