WebSocket-based Mobile Instant Communication System

Instant communication is based on Internet. The online users communicate andinteract with each other in real-time by sending and receiving text, voice, image, videoand other kinds of multimedia information through the network. This convenient way ofcommunication is popular and well received by the user’s favorite. The vast majority oftraditional instant communication applications are implemented on PC client. In recentyears, with the rapid development of mobile communication technology and increasingpopularity of smart mobile terminal, the smart mobile equipment is becoming the mainapproach people access to the Internet. So there are new requirements and broadprospect to apply the instant messaging technology to the Mobile-Internet services.Based on a practical project, this dissertation focuses on the research of mobile instantcommunication and related technologies, and designs a WebSocket-based mobile instantcommunication system.First of all it analyses the instant communication services of project, andsummarizes the basic requirements of mobile instant communication platform,including authentication, presence, contact management, instant messaging, groupservice and subscription service, then designs the basic framework of mobile instantcommunication system, including the framework of both client and server side.In this system, WebSocket connection is used in bi-directional full-duplexcommunication between client and server. On the base of researching of instantmessaging protocol such as IMPP, XMPP and the WebSocket protocol, taking thefeatures of these protocols and combining them with practical demand of system, thisdissertation designs addressing mode, message structure, communication protocol andinteraction process between client and server of the system.This dissertation studies the NodeJS technology and applies it into design anddevelopment of system server. The system server is based on service-orientedarchitecture, and consists of data service, application service, presence service and dataservice. These service entities communicate with each other via restful service interface.The data service is to provide uniform interface for data access of system, and usesNoSQL MongoDB database as underlying data store. The application service is toprovide application business such as contact management, group management andchannel management. The presence service is to manage and maintain presence information and presence subscription of clients. And the communication service,communicates with clients via WebSocket, is to provide identity authentication andinstant messaging services, and is implemented on basis of NodeJS platform andSocket.IO framework. This dissertation makes analysis and design of architecture,interface, intercommunication, and server side instant message processing.On the client side, the dissertation focuses on Android and iOS platform, studiesthe method and pattern of both Android application and iOS application development,and analyzes the basic structure of the Android client and iPhone Client. The Androidclient uses background service component and WebSocket client to realize the real-timemessage sending and receiving. The iPhone client also uses WebSocket client to sendand receive instant message, and implements real-time message push via the Apple PushNotification Service (APNs, for short).