Chat System Project

Install

How to instance and Debug

Check GOPATH

env | grep GOPATH
GOPATH=/Users/dongvt/Data/ybstudio/hope_pet/hope-pet-alice:/Users/dongvt/go

cd /Users/dongvt/go/src/
git clone https://github.com/eightybstudio/hope-pet-chat-backend.git

sudo go get -u github.com/kardianos/govendor

packge managerment for golang

govendor sync

DOCUMENT

The reason will be describe how this system works, all basic features of this chat system.

• Login with internal user
• Check user online/offline
• send message online
• Send message offline and get old

System diagram

Introduce about flow of system

After connecting into system, it will create a specific session. When ClientA send a msg to ClientB, msg will go to websocket, websocket will be not only Publisher but also Subcriber. Upon COORDINATOR it will broadcast msg to all current connections which are connecting to Server. After that, msgs are filtered and routed to correct ClientB based on ReceiveUserId. At the same time Server will store msg into table UNREAD in database. If ClientB recived msg , it will send a msg CONFIRM to confirm that already got msg. Server will remove msg in UNREAD. If user already in state offline, so when they online will send a command FETCH to fect all msgs which have not read yet. After that send command CONFIRM to remove on Server.

AUTHEN

NOTIC: URL call websocket always has 2 param to validate

ws://localhost:2345/chat/private?userId=1&session=688b23a0ffa044ad001417b52401e738

userId:  user identification
session: Chat sesion was generated by this way : md5sum(secretkey + userId + yymmddhhmm)

Purpose of session to make sure user can not be session hijack, fake user .. Make sure system is secure

Check user online/ offline

System provides a connect method websocket, client sends a heartbeat mgs every 5s to server

FLOW:

1/CLIENTA  ---------[heartbeat 5s/1] -->    SERVER
2/SERVER  --------------[ADD]------>        DATABASE
3/CLIENTB -----[check status CLIENTA] --->  SERVER
4/SERVER  -----[query DB]------------>      DATABASE
5/SERVER   ---------[STATUS]----------->    CLIENTB

Send message online

FLOW: CLIENTA send 1 msg cho CLIENTB

CLIENTA -------msg-------> SERVER
SERVER  --------msg------> DATABASE (UNREAD)
SERVER  --------msg------> CLIENTB
CLIENTB ------confirm----> SERVER
SERVER  ------remove msg--> DATABASE (UNREAD)

Send message offline.

FLOW: CLIENTA send 1 msg to CLIENTB but CLIENTB is already offline

CLIENTA -------msg-------> SERVER
SERVER  --------msg------> DATABASE (UNREAD)
CLIENTB  -------fetch------> SERVER
SERVER  --------msg[]------> CLIENTB
CLIENTB ------confirm----> SERVER
SERVER  ------remove msg--> DATABASE (UNREAD)