feature: Support Auth in Fastify GraphQL Server by mimicking Lambda E…

…vents and Context (redwoodjs#8533)

* WIP to see if graphql auth can work

* Remove debugs statements

* refactoring and documenting

* Small refactor

* plugins are needed to transform a Fastify Request to a Lambda event

* Remove unhelpful casts

packages/fastify/src/graphql.ts

@@ -1,17 +1,44 @@
+import fastifyUrlData from '@fastify/url-data'
 import type { FastifyInstance, HookHandlerDoneFunction } from 'fastify'
+import fastifyRawBody from 'fastify-raw-body'
 
-import type { GraphQLYogaOptions } from '@redwoodjs/graphql-server'
 import { createGraphQLYoga } from '@redwoodjs/graphql-server'
+import type { GraphQLYogaOptions } from '@redwoodjs/graphql-server'
+
 /**
- * Encapsulates the routes
+ * Transform a Fastify Request to an event compatible with the RedwoodGraphQLContext's event
+ * which is based on the AWS Lambda event
+ */
+import { lambdaEventForFastifyRequest as transformToRedwoodGraphQLContextEvent } from './lambda/index'
+
+/**
+ * Redwood GraphQL Server Fastify plugin based on GraphQL Yoga
+ *
+ * Important: Need to set DISABLE_CONTEXT_ISOLATION = 1 in environment variables
+ * so that global context is populated correctly and features such as authentication
+ * works properly.
+ *
+ * It is critical to set shouldUseLocalStorageContext correctly so that the `setContext` function
+ * in the `useRedwoodPopulateContext` plugin sets the global context correctly with any
+ * extended GraphQL context as is done with `useRedwoodAuthContext` that sets
+ * the `currentUser` in the context when used to authenticate a user.
+ *
+ * See: packages/graphql-server/src/globalContext.ts
+ *
  * @param {FastifyInstance} fastify  Encapsulated Fastify Instance
- * @param {Object} options plugin options, refer to https://www.fastify.io/docs/latest/Reference/Plugins/#plugin-options
+ * @param {GraphQLYogaOptions} options GraphQLYogaOptions options used to configure the GraphQL Yoga Server
  */
 export async function redwoodFastifyGraphQLServer(
   fastify: FastifyInstance,
   options: GraphQLYogaOptions,
   done: HookHandlerDoneFunction
 ) {
+  // These two plugins are needed to transform a Fastify Request to a Lambda event
+  // which is used by the RedwoodGraphQLContext and mimics the behavior of the
+  // api-server withFunction plugin
+  fastify.register(fastifyUrlData)
+  await fastify.register(fastifyRawBody)
+
   try {
     const { yoga } = createGraphQLYoga(options)
 
@@ -22,6 +49,8 @@ export async function redwoodFastifyGraphQLServer(
         const response = await yoga.handleNodeRequest(req, {
           req,
           reply,
+          event: transformToRedwoodGraphQLContextEvent(req),
+          requestContext: {},
         })
 
         for (const [name, value] of response.headers) {

packages/fastify/src/lambda/index.ts

@@ -110,7 +110,7 @@ export async function lambdaRequestHandler(
   return requestHandler(req, reply, LAMBDA_FUNCTIONS[routeName])
 }
 
-function lambdaEventForFastifyRequest(
+export function lambdaEventForFastifyRequest(
   request: FastifyRequest
 ): APIGatewayProxyEvent {
   return {

packages/graphql-server/src/globalContext.ts

@@ -19,6 +19,23 @@ export interface GlobalContext extends Record<string, unknown> {}
 let GLOBAL_CONTEXT: GlobalContext = {}
 let PER_REQUEST_CONTEXT: AsyncLocalStorage<Map<string, GlobalContext>>
 
+/**
+ *
+ * You must have shouldUseLocalStorageContext return true
+ * when you're self-hosting RedwoodJS.
+ *
+ * It is critical to set this correctly so that the `setContext` function
+ * in the `useRedwoodPopulateContext` plugin sets the global context
+ * correctly with any extended GraphQL context as is done with
+ * `useRedwoodAuthContext` that sets the `currentUser` in the context when
+ * used to authenticate a user.
+ *
+ * This will ensure that the GraphQLHandler will use the per-request context.
+ *
+ * You do not need to use LocalStorageContext for AWS (Netlify/Vercel)
+ * because each Lambda request is handled individually.
+ *
+ */
 export const shouldUseLocalStorageContext = () =>
   process.env.DISABLE_CONTEXT_ISOLATION !== '1'