189 Dev Aaron - Delete Notification Backend Route

backend/src/notifications/__test__/notification.service.test.ts

@@ -11,13 +11,15 @@ const mockScan = vi.fn().mockReturnThis();
 const mockGet = vi.fn().mockReturnThis();
 const mockSend = vi.fn().mockReturnThis(); // for SES
 const mockPut = vi.fn().mockReturnThis();
+const mockDelete = vi.fn().mockReturnThis();
 const mockQuery = vi.fn().mockReturnThis();
 const mockSendEmail = vi.fn().mockReturnThis();
 
 const mockDocumentClient = {
   scan: mockScan,
   get: mockGet,
   put : mockPut,
+  delete : mockDelete,
   promise: mockPromise,
   query : mockQuery
 };
@@ -330,5 +332,53 @@ describe('NotificationController', () => {
     });
   });
 
+  describe('deleteNotification', () => {
+    it('should successfully delete a notification given a valid id', async () => {
+      mockPromise.mockResolvedValueOnce({})
 
+      const result = await notificationService.deleteNotification('0')
+
+      expect(mockDelete).toHaveBeenCalledTimes(1)
+
+      expect(mockDelete).toHaveBeenCalledWith({
+        TableName: 'BCANNotifications',
+        Key: {
+          notificationId: '0',
+        },
+        ConditionExpression: 'attribute_exists(notificationId)'
+      })
+
+      expect(result).toEqual('Notification with id 0 successfully deleted')
+    })
+
+    it('uses the fallback table when the environment variable is not set', async () => {
+      delete process.env.DYNAMODB_NOTIFICATION_TABLE_NAME
+      mockPromise.mockResolvedValueOnce({})
+
+      const result = await notificationService.deleteNotification('0')
+
+      expect(mockDelete).toHaveBeenCalledWith({
+        TableName: 'TABLE_FAILURE',
+        Key: {
+          notificationId: '0',
+        },
+        ConditionExpression: 'attribute_exists(notificationId)'
+      })
+    })
+
+    it('throws an error when the given notification id does not exist', async () => {
+      mockPromise.mockRejectedValueOnce({
+        code: 'ConditionalCheckFailedException', 
+        message: 'The item does not exist' 
+      });
+
+      try {
+        await notificationService.deleteNotification('999');
+        throw new Error('Expected deleteNotification to throw');
+      } catch (err: any) {
+        expect(err).toBeInstanceOf(Error);
+        expect(err.message).toContain('Notification with id 999 not found');
+      }
+    })
+  })
 });

backend/src/notifications/notifcation.service.ts

@@ -132,4 +132,29 @@ export class NotificationService {
     }
   }
 
+  /**
+   * Deletes the notification with the given id from the database and returns a success message if the deletion was successful
+   * @param notificationId the id of the notification to delete
+   */
+  async deleteNotification(notificationId: string): Promise<string> {
+    const params = {
+      TableName: process.env.DYNAMODB_NOTIFICATION_TABLE_NAME || 'TABLE_FAILURE',
+      Key: {
+        notificationId,
+      },
+      ConditionExpression: 'attribute_exists(notificationId)'
+    }
+
+    try {
+      await this.dynamoDb.delete(params).promise()
+      return `Notification with id ${notificationId} successfully deleted`
+    } catch (error: any) {
+      if (error.code === "ConditionalCheckFailedException") {
+        throw new Error(`Notification with id ${notificationId} not found`)
+      }
+
+      console.error(error)
+      throw new Error(`Failed to delete notification with id ${notificationId}`)
+    }
+  }
 }

backend/src/notifications/notification.controller.ts

@@ -1,4 +1,4 @@
-import { Controller, Post, Body, Get, Query, Param } from '@nestjs/common';
+import { Controller, Post, Body, Get, Query, Param, Delete } from '@nestjs/common';
 import { NotificationService } from './notifcation.service';
 import { Notification } from '../../../middle-layer/types/Notification';
 
@@ -28,5 +28,13 @@ export class NotificationController {
     return await this.notificationService.getNotificationByUserId(userId);
   }
 
-
+  /**
+   * Deletes the notification with the given id from the database, if it exists.
+   * 
+   * @param notificationId the id of the notification to delete
+   */
+  @Delete(':notificationId')
+  async deleteNotification(@Param('notificationId') notificationId: string) {
+    return await this.notificationService.deleteNotification(notificationId);
+  }
 }