mirror of
https://github.com/hasura/graphql-engine.git
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03aff6e82e
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/2601 GitOrigin-RevId: 53c27dddd30968dd28325e3336721aa1a238815f
498 lines
20 KiB
Haskell
498 lines
20 KiB
Haskell
module Hasura.RQL.DDL.RequestTransform
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( applyRequestTransform,
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mkRequestTransform,
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RequestMethod (..),
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StringTemplateText (..),
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TemplatingEngine (..),
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TemplateText (..),
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ContentType (..),
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TransformHeaders (..),
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TransformErrorBundle (..),
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MetadataTransform (..),
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RequestTransform (..),
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)
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where
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import Control.Lens (traverseOf, view)
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import Data.Aeson qualified as J
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import Data.Bifunctor (bimap, first)
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import Data.Bitraversable
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import Data.ByteString.Lazy qualified as BL
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import Data.CaseInsensitive qualified as CI
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import Data.Either.Validation
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import Data.HashMap.Strict qualified as M
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import Data.List (nubBy)
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import Data.Text qualified as T
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import Data.Text.Encoding qualified as TE
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import Hasura.Incremental (Cacheable)
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import Hasura.Prelude hiding (first)
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import Hasura.Session (SessionVariables)
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import Kriti (RenderedError (..), runKriti)
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import Kriti.Parser (parserAndLexer)
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import Network.HTTP.Client.Transformable qualified as HTTP
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import Network.URI qualified as URI
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{-
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Request Transformations are data transformations used to modify HTTP
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Requests before those requests are executed.
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`MetadataTransform` values are stored in Metadata within the
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`CreateAction` and `CreateEventTriggerQuery` Types and then converted
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into `RequestTransform` values using `mkRequestTransform`.
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`RequestTransforms` are applied to an HTTP Request using
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`applyRequestTransform`.
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In the case of body transformations, a user specified templating
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script is applied. Currently a runtime failure of the template script
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will return the original request body.
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-}
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-------------
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--- Types ---
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-------------
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data TransformContext = TransformContext
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{ tcUrl :: J.Value,
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tcBody :: J.Value,
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tcSessionVars :: J.Value,
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tcQueryParams :: J.Value
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}
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-- | A set of data transformation functions and substitutions
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-- generated from a MetadataTransform. Nothing values mean use the
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-- original request value, unless otherwise indicated.
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data RequestTransform = RequestTransform
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{ -- | Change the request method to one provided here. Nothing means POST.
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rtRequestMethod :: Maybe RequestMethod,
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-- | A function which contructs a new URL given the request context.
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rtRequestURL :: Maybe (TransformContext -> Either TransformErrorBundle Text),
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-- | A function for transforming the request body.
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rtBody :: Maybe (TransformContext -> Either TransformErrorBundle J.Value),
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-- | Change content type to one provided here.
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rtContentType :: Maybe ContentType,
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-- | A function which contructs new query parameters given the request context.
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rtQueryParams :: Maybe (TransformContext -> Either TransformErrorBundle HTTP.Query),
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-- | A function which contructs new Headers given the request context.
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rtRequestHeaders :: Maybe (TransformContext -> Either TransformErrorBundle ([HTTP.Header] -> [HTTP.Header]))
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}
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-- | A de/serializable request transformation template which can be stored in
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-- the metadata associated with an action/event trigger/etc. and used to produce
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-- a 'RequestTransform'.
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--
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-- NOTE: This data type is _only_ intended to be parsed from and stored as user
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-- metadata; no direct logical transformations should be done upon it.
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--
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-- NOTE: Users should convert this to 'RequestTransform' as close as possible to
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-- the call site that performs a transformed HTTP request, as 'RequestTransform'
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-- has a representation that makes it more difficult to deserialize for
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-- debugging.
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--
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-- Nothing values mean use the original request value, unless
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-- otherwise indicated.
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data MetadataTransform = MetadataTransform
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{ -- | Change the request method to one provided here. Nothing means POST.
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mtRequestMethod :: Maybe RequestMethod,
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-- | Template script for transforming the URL.
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mtRequestURL :: Maybe StringTemplateText,
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-- | Template script for transforming the request body.
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mtBodyTransform :: Maybe TemplateText,
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-- | Replace the Content-Type with this value. Only
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-- "application/json" and "application/x-www-form-urlencoded" are
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-- allowed.
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mtContentType :: Maybe ContentType,
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-- | A list of template scripts for constructing new Query Params.
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mtQueryParams :: Maybe [(StringTemplateText, Maybe StringTemplateText)],
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-- | Transform headers as defined here.
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mtRequestHeaders :: Maybe TransformHeaders,
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-- | The template engine to use for transformations. Default: Kriti
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mtTemplatingEngine :: TemplatingEngine
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}
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deriving (Show, Eq, Generic)
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instance NFData MetadataTransform
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instance Cacheable MetadataTransform
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infixr 8 .=?
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(.=?) :: J.ToJSON v => k -> Maybe v -> Maybe (k, J.Value)
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(.=?) _ Nothing = Nothing
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(.=?) k (Just v) = Just (k, J.toJSON v)
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instance J.ToJSON MetadataTransform where
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toJSON MetadataTransform {..} =
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J.object $
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["template_engine" J..= mtTemplatingEngine]
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<> catMaybes
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[ "method" .=? mtRequestMethod,
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"url" .=? mtRequestURL,
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"body" .=? mtBodyTransform,
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"content_type" .=? mtContentType,
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"query_params" .=? fmap M.fromList mtQueryParams,
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"request_headers" .=? mtRequestHeaders
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]
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instance J.FromJSON MetadataTransform where
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parseJSON = J.withObject "Object" $ \o -> do
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method <- o J..:? "method"
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url <- o J..:? "url"
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body <- o J..:? "body"
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contentType <- o J..:? "content_type"
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queryParams' <- o J..:? "query_params"
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let queryParams = fmap M.toList queryParams'
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headers <- o J..:? "request_headers"
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templateEngine <- o J..:? "template_engine"
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let templateEngine' = fromMaybe Kriti templateEngine
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pure $ MetadataTransform method url body contentType queryParams headers templateEngine'
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data RequestMethod = GET | POST | PUT | PATCH | DELETE
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deriving (Show, Eq, Enum, Bounded, Generic)
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renderRequestMethod :: RequestMethod -> Text
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renderRequestMethod = \case
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GET -> "GET"
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POST -> "POST"
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PUT -> "PUT"
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PATCH -> "PATCH"
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DELETE -> "DELETE"
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instance J.ToJSON RequestMethod where
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toJSON = J.String . renderRequestMethod
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instance J.FromJSON RequestMethod where
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parseJSON = J.withText "RequestMethod" \case
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"GET" -> pure GET
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"POST" -> pure POST
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"PUT" -> pure PUT
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"PATCH" -> pure PATCH
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"DELETE" -> pure DELETE
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_ -> fail "Invalid Request Method"
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instance NFData RequestMethod
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instance Cacheable RequestMethod
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-- | Available Template Languages
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data TemplatingEngine = Kriti
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deriving (Show, Eq, Enum, Bounded, Generic)
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renderTemplatingEngine :: TemplatingEngine -> Text
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renderTemplatingEngine _ = "Kriti"
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instance J.FromJSON TemplatingEngine where
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parseJSON = J.withText "TemplatingEngine" \case
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"Kriti" -> pure Kriti
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_ -> fail "Invalid TemplatingEngine"
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instance J.ToJSON TemplatingEngine where
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toJSON = J.String . renderTemplatingEngine
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instance NFData TemplatingEngine
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instance Cacheable TemplatingEngine
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-- | Unparsed Kriti templating code
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newtype TemplateText = TemplateText {unTemplateText :: T.Text}
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deriving stock (Show, Eq, Ord, Generic)
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deriving newtype (Hashable, J.ToJSONKey, J.FromJSONKey)
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instance NFData TemplateText
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instance Cacheable TemplateText
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instance J.FromJSON TemplateText where
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parseJSON = J.withText "TemplateText" \t ->
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case parserAndLexer t of
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-- TODO: Use the parsed ValueExt in MetadataTransform so that we
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-- don't have to parse at every request.
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Right _ -> pure $ TemplateText t
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Left RenderedError {_message} -> fail $ T.unpack _message
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instance J.ToJSON TemplateText where
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toJSON = J.String . coerce
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-- | Unparsed Kriti templating code for string interpolations only.
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-- NOTE: WE are highly coupled to Kriti at this point and will likely
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-- need to rethink Kriti string interpolation when we start adding
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-- other template engines.
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newtype StringTemplateText = StringTemplateText {unStringTemplateText :: T.Text}
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deriving stock (Show, Eq, Ord, Generic)
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deriving newtype (Hashable, J.ToJSONKey, J.FromJSONKey)
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instance NFData StringTemplateText
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instance Cacheable StringTemplateText
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instance J.FromJSON StringTemplateText where
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parseJSON = J.withText "StringTemplateText" \t ->
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let wrapped = "\"" <> t <> "\""
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in case parserAndLexer wrapped of
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-- NOTE: We can't simplfy use the wrapped value because the
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-- 'FromJSONKey' instance uses coercion rather then this
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-- instance to wrap the newtype. This means we would need to
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-- handle QueryParam keys explicitly in 'mkQueryParamsTransform'
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-- while values would be handled implicitliy via this aeson
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-- instance. That is confusing, so we just handle everything
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-- explicitly down the call stack.
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Right _ -> pure $ StringTemplateText t
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Left RenderedError {_message} -> fail $ T.unpack _message
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instance J.ToJSON StringTemplateText where
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toJSON = J.String . coerce
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-- | Wrap a template with escaped double quotes.
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wrapTemplate :: StringTemplateText -> StringTemplateText
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wrapTemplate (StringTemplateText t) = StringTemplateText $ "\"" <> t <> "\""
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data ContentType = JSON | XWWWFORM
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deriving (Show, Eq, Enum, Bounded, Generic)
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renderContentType :: ContentType -> Text
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renderContentType = \case
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JSON -> "application/json"
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XWWWFORM -> "application/x-www-form-urlencoded"
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instance J.ToJSON ContentType where
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toJSON = J.String . renderContentType
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instance J.FromJSON ContentType where
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parseJSON = J.withText "ContentType" \case
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"application/json" -> pure JSON
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"application/x-www-form-urlencoded" -> pure XWWWFORM
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_ -> fail "Invalid ContentType"
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instance NFData ContentType
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instance Cacheable ContentType
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-- | This newtype exists solely to anchor a `FromJSON` instance and is
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-- eliminated in the `TransformHeaders` `FromJSON` instance.
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newtype HeaderKey = HeaderKey {unHeaderKey :: CI.CI Text}
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deriving (Show, Eq, Ord, Generic)
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instance NFData HeaderKey
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instance Cacheable HeaderKey
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instance J.FromJSON HeaderKey where
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parseJSON = J.withText "HeaderKey" \txt -> case CI.mk txt of
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"Content-Type" -> fail "Restricted Header: Content-Type"
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key -> pure $ HeaderKey key
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data TransformHeaders = TransformHeaders
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{ addHeaders :: [(CI.CI Text, StringTemplateText)],
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removeHeaders :: [CI.CI Text]
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}
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deriving (Show, Eq, Ord, Generic)
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instance NFData TransformHeaders
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instance Cacheable TransformHeaders
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instance J.ToJSON TransformHeaders where
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toJSON TransformHeaders {..} =
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J.object
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[ "add_headers" J..= M.fromList (fmap (first CI.original) addHeaders),
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"remove_headers" J..= fmap CI.original removeHeaders
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]
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instance J.FromJSON TransformHeaders where
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parseJSON = J.withObject "TransformHeaders" $ \o -> do
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addHeaders <- fromMaybe mempty <$> o J..:? "add_headers"
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let headers = M.toList $ mapKeys CI.mk addHeaders
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removeHeaders <- o J..:? "remove_headers"
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let removeHeaders' = unHeaderKey <$> fromMaybe mempty removeHeaders
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pure $ TransformHeaders headers removeHeaders'
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newtype TransformErrorBundle = TransformErrorBundle {teMessages :: [J.Value]}
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deriving stock (Show, Eq, Generic)
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deriving newtype (Semigroup, Monoid, J.ToJSON)
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instance NFData TransformErrorBundle
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instance Cacheable TransformErrorBundle
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---------------------------------------
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--- Constructing Request Transforms ---
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---------------------------------------
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-- | Construct a `RequestTransform` from its metadata representation.
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mkRequestTransform :: MetadataTransform -> RequestTransform
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mkRequestTransform MetadataTransform {..} =
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let urlTransform = mkUrlTransform mtTemplatingEngine <$> mtRequestURL
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queryTransform = mkQueryParamsTransform mtTemplatingEngine <$> mtQueryParams
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headerTransform = mkHeaderTransform mtTemplatingEngine <$> mtRequestHeaders
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bodyTransform = mkTemplateTransform mtTemplatingEngine <$> mtBodyTransform
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in RequestTransform mtRequestMethod urlTransform bodyTransform mtContentType queryTransform headerTransform
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mkQueryParamsTransform :: TemplatingEngine -> [(StringTemplateText, Maybe StringTemplateText)] -> TransformContext -> Either TransformErrorBundle HTTP.Query
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mkQueryParamsTransform engine templates transformCtx =
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let transform t =
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case mkTemplateTransform engine (coerce wrapTemplate t) transformCtx of
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Left err -> Left err
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Right (J.String str) -> Right $ str
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Right (J.Number num) -> Right $ tshow num
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Right (J.Bool True) -> Right $ "true"
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Right (J.Bool False) -> Right $ "false"
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Right val ->
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Left $
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TransformErrorBundle $
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pure $
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J.object
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[ "error_code" J..= J.String "TransformationError",
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"message" J..= J.String "Query Param Transforms must produce a String, Number, or Boolean value",
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"value" J..= val
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]
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toValidation :: [(Either TransformErrorBundle T.Text, Maybe (Either TransformErrorBundle T.Text))] -> [(Validation TransformErrorBundle T.Text, Maybe (Validation TransformErrorBundle T.Text))]
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toValidation = fmap (bimap eitherToValidation (fmap eitherToValidation))
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collectErrors :: [(Either TransformErrorBundle T.Text, Maybe (Either TransformErrorBundle T.Text))] -> Validation TransformErrorBundle [(T.Text, Maybe T.Text)]
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collectErrors xs = traverse (bitraverse id sequenceA) (toValidation xs)
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results = fmap (bimap transform (fmap transform)) templates
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collectedResults = validationToEither $ collectErrors results
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in (fmap . fmap) (bimap TE.encodeUtf8 (fmap TE.encodeUtf8)) collectedResults
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-- | Given a `TransformHeaders` and the `TransformContext`, Construct a
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-- function to transform the existing headers.
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mkHeaderTransform :: TemplatingEngine -> TransformHeaders -> TransformContext -> Either TransformErrorBundle ([HTTP.Header] -> [HTTP.Header])
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mkHeaderTransform engine TransformHeaders {..} transformCtx =
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let transform t =
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case mkTemplateTransform engine (coerce $ wrapTemplate t) transformCtx of
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Left err -> Failure err
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Right (J.String str) -> Success $ TE.encodeUtf8 str
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Right (J.Number num) -> Success $ TE.encodeUtf8 $ tshow num
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Right (J.Bool True) -> Success "true"
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Right (J.Bool False) -> Success "false"
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Right val ->
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Failure $
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TransformErrorBundle $
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pure $
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J.object
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[ "error_code" J..= J.String "TransformationError",
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"message" J..= J.String ("Header Transforms must produce a String, Number, or Boolean value: " <> tshow val)
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]
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failIfCT key =
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if CI.foldedCase key == "content-type"
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then
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Failure $
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TransformErrorBundle $
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pure $
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J.object
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[ "error_code" J..= J.String "TransformationError",
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"message" J..= J.String ("Header Transforms cannot add Content-Type" <> CI.original key)
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]
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else Success $ CI.map TE.encodeUtf8 key
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toBeAdded = traverse (bitraverse failIfCT transform) addHeaders
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toBeRemoved = (fmap . CI.map) TE.encodeUtf8 removeHeaders
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filterHeaders h = filter ((`notElem` toBeRemoved) . fst) h
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in case toBeAdded of
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Failure err -> throwError err
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Success toBeAdded' -> pure (filterHeaders . (toBeAdded' <>))
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mkUrlTransform :: TemplatingEngine -> StringTemplateText -> TransformContext -> Either TransformErrorBundle Text
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mkUrlTransform engine template transformCtx =
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case mkTemplateTransform engine (coerce $ wrapTemplate template) transformCtx of
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Left err -> Left err
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Right (J.String url) ->
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let escapedUrl = T.pack $ URI.escapeURIString (/= '|') (T.unpack url)
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in case URI.parseURI (T.unpack escapedUrl) of
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Just _ -> Right escapedUrl
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Nothing ->
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Left $
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TransformErrorBundle $
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pure $
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J.object
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[ "error_code" J..= J.String "TransformationError",
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-- TODO: This error message is not very
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-- helpful. We should find a way to identity what
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-- is wrong with the URL.
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"message" J..= J.String ("Invalid URL: " <> url)
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]
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Right val ->
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Left $
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TransformErrorBundle $
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pure $
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J.object
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[ "error_code" J..= J.String "TransformationError",
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"message" J..= J.String ("Url Transforms must produce a String value: " <> tshow val)
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]
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-- | Construct a Template Transformation function
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mkTemplateTransform :: TemplatingEngine -> TemplateText -> TransformContext -> Either TransformErrorBundle J.Value
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mkTemplateTransform engine (TemplateText template) TransformContext {..} =
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let context = [("$base_url", tcUrl), ("$body", tcBody), ("$session_variables", tcSessionVars), ("$query_params", tcQueryParams)]
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in case engine of
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Kriti -> first (TransformErrorBundle . pure . J.toJSON) $ runKriti template context
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buildTransformContext :: T.Text -> HTTP.Request -> Maybe SessionVariables -> TransformContext
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buildTransformContext url reqData sessionVars =
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TransformContext
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{ tcUrl = J.toJSON url,
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tcBody = fromMaybe J.Null $ J.decode @J.Value =<< view HTTP.body reqData,
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tcSessionVars = J.toJSON sessionVars,
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tcQueryParams = J.toJSON $ bimap TE.decodeUtf8 (fmap TE.decodeUtf8) <$> view HTTP.queryParams reqData
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}
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-- | Transform an `HTTP.Request` with a `RequestTransform`.
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--
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-- Note: we pass in the request url explicitly for use in the
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-- 'TransformContext'. We do this so that we can ensure that the url
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-- is syntactically identical to what the use submits. If we use the
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-- parsed request from the 'HTTP.Request' term then it is possible
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-- that the url is semantically equivalent but syntactically
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-- different. An example of this is the presence or lack of a trailing
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-- slash on the URL path. This important when performing string
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-- interpolation on the request url.
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--
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-- Because of this requirement, we must ensure the sequence of
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-- transformation applications. If a query param transformation
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-- occured before the url transformation then the query param
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-- transformation would be wiped out.
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applyRequestTransform :: T.Text -> RequestTransform -> HTTP.Request -> Maybe SessionVariables -> Either TransformErrorBundle HTTP.Request
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applyRequestTransform reqUrl RequestTransform {..} reqData sessionVars =
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let transformCtx = buildTransformContext reqUrl reqData sessionVars
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method = fmap (TE.encodeUtf8 . renderRequestMethod) rtRequestMethod
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bodyFunc :: Maybe BL.ByteString -> Either TransformErrorBundle (Maybe BL.ByteString)
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bodyFunc body =
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case rtBody of
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Nothing -> pure body
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Just f -> pure . J.encode <$> f transformCtx
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urlFunc :: Text -> Either TransformErrorBundle Text
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urlFunc url =
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case rtRequestURL of
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Nothing -> pure url
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Just f -> f transformCtx
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queryFunc :: HTTP.Query -> Either TransformErrorBundle HTTP.Query
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queryFunc query =
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case rtQueryParams of
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Nothing -> pure query
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Just f -> f transformCtx
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headerFunc :: [HTTP.Header] -> Either TransformErrorBundle [HTTP.Header]
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headerFunc headers =
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case rtRequestHeaders of
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Nothing -> pure headers
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Just f -> f transformCtx >>= \g -> pure $ g headers
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contentTypeFunc :: [HTTP.Header] -> Either TransformErrorBundle [HTTP.Header]
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contentTypeFunc = pure . nubBy (\a b -> fst a == fst b) . (:) ("Content-Type", contentType)
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where
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contentType = maybe "application/json" (TE.encodeUtf8 . renderContentType) rtContentType
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in reqData & traverseOf HTTP.url urlFunc
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>>= traverseOf HTTP.body bodyFunc
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>>= traverseOf HTTP.queryParams queryFunc
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>>= traverseOf HTTP.method (pure . (`fromMaybe` method))
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>>= traverseOf HTTP.headers headerFunc
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>>= traverseOf HTTP.headers contentTypeFunc
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