feat: refactor get note pipe to interceptor

This is necessary, because of the order of operations in nestjs, the validation pipe is not able to get the note as the noteIdOrAlias will be transformed by the get note pipe after the validation did run.

Signed-off-by: Philip Molares <philip.molares@udo.edu>

src/api/utils/get-note.interceptor.ts

@@ -4,29 +4,39 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 import {
-  ArgumentMetadata,
   BadRequestException,
+  CallHandler,
+  ExecutionContext,
   Injectable,
+  NestInterceptor,
   NotFoundException,
-  PipeTransform,
 } from '@nestjs/common';
+import { Request } from 'express';
+import { Observable } from 'rxjs';
 
 import { ForbiddenIdError, NotInDBError } from '../../errors/errors';
-import { ConsoleLoggerService } from '../../logger/console-logger.service';
 import { Note } from '../../notes/note.entity';
 import { NotesService } from '../../notes/notes.service';
+import { User } from '../../users/user.entity';
 
+/**
+ * Saves the note identified by the `noteIdOrAlias` URL parameter
+ * under the `note` property of the request object.
+ */
 @Injectable()
-export class GetNotePipe implements PipeTransform<string, Promise<Note>> {
+export class GetNoteInterceptor implements NestInterceptor {
-  constructor(
+  constructor(private noteService: NotesService) {}
-    private readonly logger: ConsoleLoggerService,
-    private noteService: NotesService,
-  ) {
-    this.logger.setContext(GetNotePipe.name);
-  }
 
-  async transform(noteIdOrAlias: string, _: ArgumentMetadata): Promise<Note> {
+  async intercept<T>(
-    return await getNote(this.noteService, noteIdOrAlias);
+    context: ExecutionContext,
+    next: CallHandler,
+  ): Promise<Observable<T>> {
+    const request: Request & { user: User; note: Note } = context
+      .switchToHttp()
+      .getRequest();
+    const noteIdOrAlias = request.params['noteIdOrAlias'];
+    request.note = await getNote(this.noteService, noteIdOrAlias);
+    return next.handle();
   }
 }
 

src/api/utils/permissions.guard.ts

@@ -12,7 +12,7 @@ import { NotesService } from '../../notes/notes.service';
 import { Permission } from '../../permissions/permissions.enum';
 import { PermissionsService } from '../../permissions/permissions.service';
 import { User } from '../../users/user.entity';
-import { getNote } from './get-note.pipe';
+import { getNote } from './get-note.interceptor';
 
 /**
  * This guards controller methods from access, if the user has not the appropriate permissions.
@@ -50,7 +50,7 @@ export class PermissionsGuard implements CanActivate {
       return this.permissionsService.mayCreate(user);
     }
     // Get the note from the parameter noteIdOrAlias
-    // Attention: This gets the note an additional time if used in conjunction with GetNotePipe
+    // Attention: This gets the note an additional time if used in conjunction with GetNoteInterceptor
     const noteIdOrAlias = request.params['noteIdOrAlias'];
     const note = await getNote(this.noteService, noteIdOrAlias);
     switch (permissions[0]) {