📩 Message Service

Github: github.com/le-minh-duc-dev/chat-system-message-service.git

The Message Service is responsible for persisting chat messages within the Chat System.
It consumes messages from Kafka topics produced by the Chat Service and stores them in a relational database for retrieval and history features.

📜 Features

Kafka Message Consumption
Listen to Kafka topics and consume incoming chat messages asynchronously.
Message Persistence
Save received messages into the database for long-term storage and chat history reconstruction.
Scalable and Fault-Tolerant
Designed for high throughput, with support for partitioned Kafka topics and consumer groups.
Structured Message Model
Define and enforce message schemas (e.g., sender, receiver, content, timestamp) for consistency.
Infinite Scroll & Unseen Messages Support Optimized to support infinite scroll pagination for chat history and "unseen messages" logic using per-user, per-room lastSeen timestamps.

🧰 Technology Stack

Spring Boot
Spring Kafka
Spring Data JPA
Spring Data Redis
PostgreSQL
Apache Kafka
Spring Cloud OpenFeign
Spring Cloud Netflix Eureka
Spring Cloud Config

📂 Kafka Listener Overview

Topic Name	Description	Group ID
`chat-messages`	Receives chat messages from the Chat Service	`message-service-group`

🧭 Message Processing Flow

📂 Endpoints Overview

🌐 REST API (HTTP)

Method	Endpoint	Description
GET	`/api/v1/messages?chatRoomId={id}&messageId={id}&type={type}`	Fetch chat messages in infinite scroll mode (older or newer) using messageId as anchor.
GET	`/api/v1/messages/last_seen?chatRoomId={id}`	Fetch messages from the user’s last seen timestamp in the given chat room.

📁 Data Contracts

Message Payload (`MessageDTO`)

{
  "id": "812738129374812160",
  "senderId": "1",
  "roomId": "1",
  "content": "Hello!",
  "type":"GROUP"
  "timestamp": "2025-04-29T15:23:00"
}

InfiniteScroll Messages Payload (`InfiniteScrollResult<MessageDTO>`)

{
  "data": "[]",
  "hasMoreOnTop": "false",
  "hasMoreOnBottom": "false"
}