Session decorators: Inject from SessionHost

Author: CarsonF

src/common/session.ts

@@ -1,6 +1,6 @@
 import {
-  createParamDecorator,
-  type ExecutionContext,
+  Injectable,
+  Param,
   type PipeTransform,
   type Type,
 } from '@nestjs/common';
@@ -9,6 +9,7 @@ import { Context } from '@nestjs/graphql';
 import { uniq } from 'lodash';
 import { type DateTime } from 'luxon';
 import { NoSessionException } from '../components/authentication/no-session.exception';
+import { SessionHost } from '../components/authentication/session.host';
 import { type ScopedRole } from '../components/authorization/dto';
 import { type GqlContextType } from './context.type';
 import { UnauthenticatedException } from './exceptions';
@@ -49,30 +50,32 @@ export const sessionFromContext = (context: GqlContextType) => {
   return session;
 };
 
+@Injectable()
+export class SessionPipe implements PipeTransform {
+  constructor(private readonly sessionHost: SessionHost) {}
+
+  transform() {
+    return this.sessionHost.current$.value;
+  }
+}
+
 export const LoggedInSession = () =>
   AnonSession({ transform: loggedInSession });
 
 export const AnonSession =
   (...pipes: Array<Type<PipeTransform> | PipeTransform>): ParameterDecorator =>
   (...args) => {
-    Context({ transform: sessionFromContext }, ...pipes)(...args);
+    Context(SessionPipe, ...pipes)(...args);
     process.nextTick(() => {
       // Only set this metadata if it's a controller method.
       // Waiting for the next tick as class decorators execute after methods.
       if (Reflect.getMetadata(CONTROLLER_WATERMARK, args[0].constructor)) {
-        HttpSession(...pipes)(...args);
+        Param(SessionPipe, ...pipes)(...args);
         SessionWatermark(...args);
       }
     });
   };
 
-// Using Nest's custom decorator so that we can pass pipes.
-const HttpSession = createParamDecorator(
-  (_data: unknown, ctx: ExecutionContext) => {
-    return ctx.switchToHttp().getRequest().session;
-  },
-);
-
 const SessionWatermark: ParameterDecorator = (target, key) =>
   Reflect.defineMetadata('SESSION_WATERMARK', true, target.constructor, key!);
 

src/components/authentication/authentication.module.ts

@@ -1,5 +1,6 @@
 import { forwardRef, Global, Module } from '@nestjs/common';
 import { APP_INTERCEPTOR } from '@nestjs/core';
+import { SessionPipe } from '~/common/session';
 import { splitDb } from '~/core';
 import { AuthorizationModule } from '../authorization/authorization.module';
 import { UserModule } from '../user/user.module';
@@ -43,6 +44,7 @@ import { SessionResolver } from './session.resolver';
     GelCurrentUserProvider,
     { provide: APP_INTERCEPTOR, useExisting: GelCurrentUserProvider },
     { provide: SessionHost, useClass: SessionHostImpl },
+    SessionPipe,
   ],
   exports: [
     SessionHost,

src/core/http/types.ts

@@ -4,7 +4,6 @@ import type {
   FastifyReply as Response,
   RouteShorthandOptions,
 } from 'fastify';
-import type { Session } from '~/common';
 
 // Exporting with I prefix to avoid ambiguity with web global types
 export type { Request as IRequest, Response as IResponse };
@@ -19,12 +18,6 @@ export type HttpHooks = Required<{
 export type { FastifyCorsOptions as CorsOptions } from '@fastify/cors';
 export type { SerializeOptions as CookieOptions } from '@fastify/cookie';
 
-declare module 'fastify' {
-  export interface FastifyRequest {
-    session?: Session;
-  }
-}
-
 declare module '@nestjs/common/interfaces/features/arguments-host.interface' {
   export interface HttpArgumentsHost {
     getRequest(): Request;