| Safe Haskell | Safe-Inferred |
|---|---|
| Language | Haskell2010 |
Hasura.RQL.DDL.Webhook.Transform
Description
Webhook Transformations are data transformations used to modify HTTP Requests/Responses before requests are executed and after responses are received.
Transformations are supplied by users as part of the Metadata for a
particular Action or EventTrigger as a RequestTransform
record. Per-field Transformations are stored as data
(defunctionalized), often in the form of a Kriti template, and then
converted into actual functions (reified) at runtime by the
Transform typeclass.
We take a Higher Kinded Data (HKD) approach to representing the
transformations. RequestFields is an HKD which can represent the
actual request data as 'RequestFields Identity' or the
defunctionalized transforms as 'RequestFields (WithOptional
TransformFn)'.
We can then traverse over the entire RequestFields HKD to reify
all the fields at once and apply them to our actual request
data.
NOTE: We don't literally use traverse or the HKD equivalent
btraverse, but you can think of this operation morally as a
traversal. See applyRequestTransform for implementation details.
Synopsis
- applyRequestTransform :: forall m. MonadError TransformErrorBundle m => (Request -> RequestContext) -> RequestTransformFns -> Request -> m Request
- data ResponseTransform = ResponseTransform {}
- buildRespTransformCtx :: Maybe RequestContext -> Maybe SessionVariables -> TemplatingEngine -> ByteString -> Int -> ResponseTransformCtx
- mkResponseTransform :: MetadataResponseTransform -> ResponseTransform
- applyResponseTransform :: ResponseTransform -> ResponseTransformCtx -> Either TransformErrorBundle ByteString
- mkRequestContext :: RequestTransformCtx -> RequestContext
Documentation
applyRequestTransform :: forall m. MonadError TransformErrorBundle m => (Request -> RequestContext) -> RequestTransformFns -> Request -> m Request Source #
Transform an Request with a RequestTransform.
Note: we pass in the request url explicitly for use in the
ReqTransformCtx. We do this so that we can ensure that the url
is syntactically identical to what the use submits. If we use the
parsed request from the Request term then it is possible
that the url is semantically equivalent but syntactically
different. An example of this is the presence or lack of a trailing
slash on the URL path. This important when performing string
interpolation on the request url.
data ResponseTransform Source #
A set of data transformation functions generated from a
MetadataResponseTransform. Nothing means use the original
response value.
Constructors
| ResponseTransform | |
buildRespTransformCtx :: Maybe RequestContext -> Maybe SessionVariables -> TemplatingEngine -> ByteString -> Int -> ResponseTransformCtx Source #
A helper function for constructing the ResponseTransformCtx
applyResponseTransform :: ResponseTransform -> ResponseTransformCtx -> Either TransformErrorBundle ByteString Source #
At the moment we only transform the body of
Responses. 'http-client' does not export the constructors for
Response. If we want to transform other fields then we will need
additional apply functions.