Money-Manager (backend)

The main purpose of the application is to manage income, expenses and savings.

It is a stateless backend REST API with oAuth2 authorization.

User data stores in PostgreSQL database.

Core technologies:

• Java 21
• Spring Boot 3.2.2
• PostgreSQL 16.1
• Maven

Security

OAuth2 authentication through Google or VKontakte

Implemented by spring-boot-starter-oauth2-client but customized to remove sessions and make the application stateless RESTful API with JWT token

Schema:

• Frontend requests this backend API like this: http://localhost:8080/oauth2/authorize/google?redirect_uri=http://localhost:3000/oauth2/redirect
• Backend redirects frontend to chosen provider (Google or VK) login page with specific provider credentials (client_id, client_secret, etc.) and redirect_uri param which provider will use to send response to the backend. Example with Google:
  • https://accounts.google.com/o/oauth2/v2/auth?response_type=code&client_id=CLIENT_ID&scope=email+profile&state=STATE&redirect_uri=http://localhost:8080/oauth2/callback/google
• User sees his login page, accept authentication of our app or not
• Backend handles response from provider on http://localhost:8080/oauth2/callback/PROVIDER
  • if it is successfully authenticated then redirects back to the frontend with new JWT token like this: http://localhost:3000/oauth2/redirect?token=TOKEN. Oauth2AuthenticationSuccessHandler
  • If it is failed then like this: http://localhost:3000/oauth2/redirect?error=error. Oauth2AuthenticationFailureHandler

See details in HttpCookieOauth2AuthorizationRequestRepository.java

Instructions

Build and run

• Run PostgreSQL by docker-compose.yml
• Change GOOGLE_CLIENT_ID, GOOGLE_CLIENT_SECRET and other credentials in .env (or as environment variables) to actual
• Call mvn clean package at root of the project to build the application. -Drevision=1.0.0 can be added to change the version of the project
• Built result (jar file) will be in 'target' directory at the root of the project
• Call java -Duser.timezone=UTC -jar money-manager-<version>.jar to start the application