How alif10151/simple_listing_website works
1. High-level shape
- This repo is a two-part full-stack application: a React single-page frontend in client/ and a Go backend in backend/.
- The README describes a MERN stack, but the actual backend tree is Go + SQL, not Node/Express + MongoDB. That mismatch is important for an architecture diagram.
2. Frontend boundary
- client/ is a classic React app with page components, reusable UI components, a small API service layer, and CSS-based styling.
- src/pages contains route-level screens like HomePage, SingleProductPage, and NotFoundPage.
- src/components contains the product UI primitives: list, card, and add/edit form.
- src/services/api.js is the main boundary to the backend; it centralizes HTTP calls rather than letting components talk directly to the server.
3. Frontend data flow
- User interactions happen in page/components, which call the API service.
- The UI renders product collections, single-product details, and add/edit forms, then refreshes state from server responses after CRUD operations.
- Routing is handled on the client side, so the backend is primarily an API provider rather than a page renderer.
4. Backend entrypoint and composition
- The backend starts from backend/main.go and backend/cmd/serve.go, which likely bootstrap configuration, database access, and the HTTP server.
- backend/config/config.go reads runtime configuration, including environment-based settings.
- backend/rest/server.go is the HTTP composition root: it wires routes, middleware, and handlers together.
5. REST API layer
- The API is organized by resource under backend/rest/handlers/product and backend/rest/handlers/user.
- Product handlers implement create, read, update, delete, and collection retrieval.
- User handlers implement user creation and login.
- Each resource has its own handler.go, routes.go, and port.go, which suggests a clean separation between HTTP concerns and business logic.
6. Middleware and cross-cutting concerns
- backend/rest/middlewares contains CORS handling, preflight handling, structured logging, and JWT authentication.
- authenticate_jwt.go is the key security boundary for protected endpoints.
- manager.go and middleware.go indicate middleware composition is centralized instead of scattered across handlers.
7. Business/service layer
- The domain logic is split into backend/product and backend/user.
- These packages expose service.go and port.go, which suggests use of interfaces to decouple services from handlers and persistence.
- This layer is the main place where application rules would live, while handlers remain thin.
8. Domain model
- backend/domain/product.go and backend/domain/user.go define the core entities used across the backend.
- These types are the shared contract between HTTP, service, and repository layers.
- The architecture is centered on these domain objects rather than on framework-specific models.
9. Persistence layer
- backend/repo/product.go and backend/repo/user.go implement data access.
- backend/infrastructure/db/connections.go and migrate.go manage database connectivity and schema migration support.
- The presence of backend/migrations/*.up.sql and *.down.sql, plus backend/db_queries/*.sql, indicates raw SQL with explicit schema/version control rather than an ORM.
10. Database boundary
- The backend persists products and users in a relational-style database schema.
- Migrations create and evolve the users and products tables.
- The db_queries folder suggests some operations are defined as standalone SQL files, which keeps SQL close to the repo and makes query behavior explicit.
11. Authentication flow
- User login goes through the user handler, then the user service/repo, and on success a JWT is created in backend/utility/create_jwt.go.
- Authenticated requests are then validated by the JWT middleware before reaching protected handlers.
- This makes authentication a cross-cutting concern rather than part of product logic.
12. Shared utilities
- backend/utility/send_data.go likely standardizes JSON/API responses.
- Centralized helpers like this reduce duplication across handlers and make response shape consistent.
13. End-to-end request path
- A typical product request flows: React component → client/src/services/api.js → Go REST server → middleware → product handler → service → repository → DB → back through the same layers to the UI.
- A login request follows the same path, but returns a JWT that is then used on subsequent protected calls.
14. What to draw in the architecture diagram
- Show two top-level subsystems: React frontend and Go API backend.
- Inside the backend, show four layers: REST handlers/middleware, service layer, repository layer, and DB/migrations.
- Show JWT-based auth and CORS/logging as cross-cutting middleware.
- Show the frontend communicating only through the API service layer, not directly with the database or backend internals.
Main entry points: server.go REST server · service.go User service · db DB layer · pages Pages
Components 20
Frontend
React SPA and UI layer
- App · Client-side router and app composition
client/src/App.js - Pages · Home, single product, and not-found screens
client/src/pages - Components · Product list, card, and add/edit form
client/src/components - API service · Centralized calls to the backend API
client/src/services/api.js
Backend
Go API and application logic
- Main · Program entrypoint and server startup
backend/main.go - Config · Environment and application settings
backend/config/config.go - REST server · Wires routes, middleware, and handlers
backend/rest/server.go - Middleware · CORS, preflight, logging, and JWT auth
backend/rest/middlewares/manager.go - Product API · CRUD endpoints for products
backend/rest/handlers/product - User API · User creation and login endpoints
backend/rest/handlers/user - Product service · Product rules and orchestration
backend/product/service.go - User service · User rules and authentication flow
backend/user/service.go - Product repo · Product persistence access
backend/repo/product.go - User repo · User persistence access
backend/repo/user.go - Domain models · Shared product and user types
backend/domain - JWT helper · Creates signed login tokens
backend/utility/create_jwt.go - Response helper · Standardized API responses
backend/utility/send_data.go
Data
SQL persistence and migrations
- DB layer · Connections and migration support
backend/infrastructure/db - Migrations · SQL up/down migrations for tables
backend/migrations - SQL queries · Explicit query files for CRUD operations
backend/db_queries
Connections 24
- App → Pages: renders · App composes route-level screens
- Pages → Components: uses · Pages assemble reusable product UI
- Components → API service: calls · User actions trigger API requests
- Pages → API service: calls · Screens fetch and refresh server data
- API service → REST server: HTTP · Frontend talks to the Go REST API
- Main → Config: loads · Startup reads runtime settings
- Main → REST server: starts · Entrypoint boots the HTTP server
- REST server → Middleware: applies · Request pipeline includes middleware
- REST server → Product API: routes · Product endpoints are mounted
- REST server → User API: routes · User endpoints are mounted
- Middleware → JWT helper: auth · Protected requests validate JWTs
- Product API → Product service: uses · Handlers delegate product logic
- User API → User service: uses · Handlers delegate user logic
- Product service → Product repo: persists · Product service reads and writes data
- User service → User repo: persists · User service reads and writes data
- Product service → Domain models: models · Service operates on shared entities
- User service → Domain models: models · Service operates on shared entities
- Product repo → DB layer: connects · Repository uses database connections
- User repo → DB layer: connects · Repository uses database connections
- DB layer → Migrations: migrates · Schema is managed through SQL migrations
- DB layer → SQL queries: runs · Queries are stored as explicit SQL files
- User service → JWT helper: issues token · Login returns a signed JWT
- Product API → Response helper: responds · Handlers format API responses
- User API → Response helper: responds · Handlers format API responses