backend-nest-js-experiments

Simple NestJS backend for study.

Default user

• Email: admin@example.com
• Password: 123456

Quick start (Docker Compose)

Prerequisites

• Docker & Docker Compose installed
• (For running tests locally) Node.js 18+ and npm

Environment

• Configure .env in the project root. Example values are already provided in .env and aligned with docker-compose.yml (DB on port 3306, DB_NAME=nest, DB_USER=root, DB_PASS=password).

Run (development)

• Option A — install dependencies on host (recommended for fast dev; container will use host node_modules):

  1. Open cmd.exe in project folder:

     npm ci
     docker-compose up
     

  2. If container already running, restart the app service:

     docker-compose restart app
     

• Option B — let the image install dependencies (image contains node_modules in a volume):

  1. Build and run:

     docker-compose down -v
     docker-compose up --build
     

  2. To force a fresh install without cache:

     docker-compose build --no-cache
     docker-compose up
     

Notes on node_modules and caching

• If you prefer to install deps on host and avoid rebuilding images when adding packages, use Option A.
• If you use Option B, avoid mounting host code in a way that hides the container node_modules. If you encounter missing packages inside the container (e.g. class-transformer), either install on host (npm ci) or rebuild the image.

Database persistence

• The compose file uses a named volume for MySQL (db_data). To keep DB data across restarts, do NOT run:

  docker-compose down -v
  

  (that removes volumes and deletes DB data).
• To back up the DB:

  docker exec -i mysql_db mysqldump -u root -ppassword nest > backup_nest.sql
  

• To restore:

  docker exec -i mysql_db mysql -u root -ppassword nest < backup_nest.sql
  

Run tests (local)

• Unit + integration tests:

  npm test
  

• E2E tests:

  npm run test:e2e
  

• If running tests inside the running container:

  docker exec -it nestjs_app npm test
  docker exec -it nestjs_app npm run test:e2e
  

Troubleshooting

• If Swagger UI at /api/docs shows empty schemas, ensure DTOs/controllers have @ApiProperty() and @ApiTags() (files are updated).
• If container reports missing package right after docker-compose up --build, run:

  docker-compose down -v
  docker-compose up --build
  

  or install on host (npm ci) and docker-compose up.

Useful commands

• Start services in background:

  docker-compose up -d
  

• View logs:

  docker-compose logs -f app
  

• Stop services:

  docker-compose down
  

CORS Configuration

The server enables CORS globally in main.ts.

Environment variable: CORS_ORIGINS

Format: comma-separated list of allowed origins.

Example:

CORS_ORIGINS=http://localhost:5173,http://localhost:4200

Behavior:

• If CORS_ORIGINS is set, only those origins are allowed.
• If not set, all origins are allowed (development convenience). For production, set an explicit list.

Headers allowed: Content-Type, Authorization

Credentials: enabled (credentials: true). If your frontend needs cookies, keep this. If you only use Authorization headers, it's still fine.

If you face a CORS error in the browser:

1. Confirm the frontend origin matches exactly (scheme, host, port) one of the entries in CORS_ORIGINS.
2. Ensure no trailing slashes in the origin list.
3. Restart the backend after changing env vars.