Design And Implementation Of Online Messaging System For Enterprise

Since the advent of the first instant messaging software ICQ in1996, instant communication software has gained a world-wide popularity. In China it has ranked the first on the Internet application. With the development over ten years, various kinds of instant messaging software are different in market share but similar in terms of the function and use method. And people gradually tend to share the similar habits.This paper describes a development process of instant messaging software which is suitable for enterprises. In addition to instant messaging transceiver, image and file transmission, message arrival reminder, the user state reminder, offline messages, and custom avatar, its function can be expanded through the edition of expansion module. For example, instant message content filtering, the integration of instant messages to mobile phone users or to enterprise office automation (OA) system, are expected to send messages between OA system and the instant messaging system.Consisting of client and server, this instant messaging software is written in C++language, and its system structure takes the C/S structure as the priority and P2P structure as the supplemented, in which P2P is only for binary data, such as the transfers between the client files.The server uses the epoll multiplex I/O model to run on the Linux system and the client uses Visual C++run on the Windows. The TCP protocol between clients and servers are used but RUTP, a private protocol specially developed, shares communication with TCP protocol between clients. Messages help exchange data between clients and servers. The server uses a database for user data storage, with the default MySql database management system. Meanwhile, a standard database access is written in the base class by servers, based on object-oriented inheritance and polymorphism, to support different types of databases.This paper is divided into seven chapters:Chapter1describes the background, the purpose and the significance of the project. Chapter2is about technical analysis, focusing on the working principles and the functions of epoll I/O mechanism. Also, the important technologies in system design, including communication protocol, socket programming, encryption technology are covered.Chapter3probes into the requirements analysis, including functional requirements, non functional requirements and function-oriented module division.The fourth chapter describes the process of system design. The main work is about the modeling of the system by UML, including use case modeling and use case diagramming, static model establishing and a class diagramming, dynamic modeling and a sequence diagramming, state diagramming as well as activity diagramming, the deployment diagramming, and finally the database modeling and the establishment of a table structure and draw the E-R diagram according to functions.The fifth chapter is about the system implementation. The implementation process of the master server, data stream transfer server and clients are described and the flow chart of some important modules and their implementation codes are presented.The sixth chapter is about the system test. The system is tested from the function, the performance, the usability, the reliability, the compatibility and the security. And the test result is presented.In the seventh chapter, the summary and prospect of the system are summarized, pointing out the shortcomings of the system as well as the future trend of the development.