Research And Implementation Of Instant Messaging Client On IOS Base XMPP Protocal

The Internet provides text, images, voice, video and other rich variety of media way to satisfy People’s Daily communication, and social network is one of the most popular ways of communication on the Internet. XMPP is an open source real-time communication protocol based on XML with strong scalability. It becomes one of the most popular instant messaging protocol. With smartphones growing popularity, people’s demands and the iOS mobile device users are also increasing. However, for the XMPP protocol of open source framework, iOS platform has some deficiencies under audio compression and data concurrency technology, resulting in slow of the voice transmission and inefficient of system resources.To solve the above problems, this paper optimizes the existing XMPP open source framework, introducing audio compression into the framework. The integrated use of cache design, multi-threading and information push technology to optimize the use of system resources such as efficiency, and realize stable and efficient IM software on the iOS platform. The main working point has the following three aspects:Firstly of all, improves the method of Speex audio data compression in the wireless network environment. The method called Code Excited Linear Prediction (CELP) simplifies the filtering of the perceptual enhancement to reduce CPU computing complexity under the condition of high compression ratio. These measures guarantee the low latency of the audio data transmission.Secondly, optimizes the query results. Uses Skyline query process the LDAP search results according to the correlation of the query correlation and users, and analyses the relationship among data attributes to ensure the query results are optimized sorting. As a result, the best search result should be on the top of the view.Then, applies the GCD concurrent programming technology based on the block objects and scheduling queue to make tasks that will be processed encapsulated in block object, then system based on available process resource schedule these tasks, in order to obtain better performance than traditional multi-threading technology.Finally, this paper implements iPhone IM client based on XMPP protocol, complete audio compression based on Speex algorithm. According testing, this client can satisfy the requirement of actual requirements such as in memory, CPU resource usage, audio compression rate, response speed, etc. In the future, the client’s function can be extended on the current basis. The XMPP protocol not just for instant messaging, but also in the field of video and file transfer, has a great potential ability.