Spring Boot Private Chat Project

1-1 instant messaging project designed to demonstrate WebSockets in a load-balanced environment. Users can register, login/logout, see a friendslist, private message, and send/receive notifications. WebSocket usages include user presence monitoring, notifications, and chat messages.

Notable Technologies/Design Decisions

• Backend: Java 8 with Spring Boot
• Frontend: Angular.js
• Message Broker: RabbitMQ (PubSub pattern for multi-server messaging)
• Database: MySQL
• ORM: Hibernate
• WebSocket messaging protocol: Stomp
• WebSocket handler: Sock.js (with cross-browser fallbacks)
• Session Management: Spring Session Redis (works cross-server)
• Security: Spring Security
• Spring Controllers couple REST as well as WebSocket traffic
• Fractal Design

Setup

1. Install system dependencies: latest versions (at the time of this writing) of Java, MySQL, Redis, RabbitMQ, Node, NPM
2. Install RabbitMQ Stomp plugin: $ sudo rabbitmq-plugins enable rabbitmq_stomp
3. Update src/main/resources/application.properties with your MySQL credentials and port
4. Execute src/main/java/org/privatechat/shared/database/createDatabase.sql to create the database
5. Execute src/main/java/org/privatechat/shared/database/seedDatabase.sql to seed the database with some users (passwords are bcrypted, but they are all "testtest")
6. cd to src/main/resources/ and run $ sudo npm install && gulp
7. cd to root of the project and execute $ mvn spring-boot:run or ($ mvn spring-boot:run -Drun.jvmArguments='-Dserver.port={{your port here}}' if you wish to run a few servers)
8. Visit http://localhost:8080/

Notes

• Chat messages are persisted to the database, notifications are not. Will add that functionality later.
• Uncomment devtools dependency in pom.xml for live reloading in development
• Notifications must be subscribed to in unique per-user channels. Despite enabling the /user message broker prefix, Spring's convertAndSendToUser(...) failed to update all nodes of a notification message transmission. Going to post a SO question soon!
• Friendlist feature is just every user in the database other than the current user (simple feature for demo, not meant to be realistic)
• Chat messages are LIMITed by 100

Todos

• Separate out index.js file into smaller services/configs
• Persist notifications
• Figure out how to have Spring Security return a custom UserDTO on /login. Currently, after login, a call to /api/user/requesting/info is made and the Principal context drives the rest. Not elegant.
• Refactor user table isPresent (boolean) to be numberOfConnections (int).
• Implement notification emailer when recieving user is offline (batch up notifications in a time window)
• Implement auto-logout timer on frontend
• Implement smart pagination of messages on the frontend
• Implement a UUID for notifications topics subscription (currently using user id, which is unsecure)
• Wire up CSRF tokens with Spring Security
• ChatService.getExistingChatMessages(...) currently reverses the List<ChatMessageDTO collection because the query needs some attention.
• Handle frontend exception when requested chat user doesn't exist on the frontend
• Clean up hacky notifications SCSS
• Improve the way global error handler intercepts HTTPs responses
• Switch all e.printStackTrace to use the logger

License

MIT