Socket.io

Events

Event Name	Description
online	Used for retrieving and updating currently online buddies for the client
message	Used for sending and receiving messages
read	Used for marking sent and received messages as read

Client to server

Event Name	Description	Request Body
message	Send a message event to the server of sender, receiver and the message it self	{ senderId: Long, receiverId: Long, message: String, timestamp: DateTime, }
read	Send a read event to the server containing receiver id whose message was read	{ receiverId: Long, timestamp: DateTime, }

Server to client

Event Name	Description	Response Body
message	Broadcast a message event to the receiver of the message	{ senderId: Long, receiverId: Long, message: String, timestamp: DateTime, }
read	Broadcast a read event to the sender of the message	{ buddyId: Long, }
online	Broadcast online event, when an update in online buddies occurs, to a client user containing a list of all the online added buddies	[{ senderId: Long, receiverId: Long, message: String, timestamp: DateTime, }]

Frontend (client) usage

The client side socket functionality is contained in /src/api/sockets/Socket.js.

This is a react context that wraps the application and exposes these methods to be used:

Functionality	Description
connected	Boolean value for whether the client's socket is connected to the server
connect	Function for creating a socket and establishing a connection between the client and the server
disconnect	Function for destroying the socket and closing the connection between the client and the server
sendMessageEvent	Function for sending a message from the current client to a receiving client
sendReadEvent	Function for sending a read message event from current client to a receiving client
onMessageEvent	Listener that executes a passed in call back whenever a new message event comes in to the current client
onOnlineEvent	Listener that executes a passed in call back whenever a new buddy comes online

Backend (server) usage

The server side socket functionality is contained in /src/main/java/socket/ChatEventHandler.java

This class contains the following relevant methods:

Method	Description
onMessageReceived	Listener that sends message to the receiver when it receives a message event
onReadReceived	Listener that sends read notice to the buddy when it receives a read event
onConnected	Listener that stores current user connected and reports online users to all users
onDisconnected	Listener removes current user from store and reports online users to all users
sendMessage	Broadcasts a message event to the receiving client
sendOnline	Broadcasts an online event to the current client containing a list of all the online buddies
sendRead	Broadcast a read event to the receiving client for a given message

Further information and examples

For more documentation about socket.io please refer to the official socket.io documentation.

For specific Socket.IO server implementation used refer to the netty socket.io implementation on github.