移动Web客户端持久化缓存技术研究

发布时间：2018-06-26 10:52

本文选题：移动Web + 客户端缓存　；参考：《华中科技大学》2013年硕士论文

【摘要】：由于移动网络带宽低，延迟高，间歇性连通等缺点，Web用户通过移动网络与服务器交互获取或提交数据时，可能出现响应延迟高，甚至网络突然中断导致的Web服务不可用。客户端缓存技术是解决上述问题的有效手段，但是传统的浏览器缓存机制在移动网络下具有局限性：（1）浏览器单向缓存特性不能缓存其提交给服务器的数据，断网提交数据丢失，提交操作延迟；（2）验证机制要求浏览器必须获取服务器验证结果才能读取缓存数据，网络突然中断将导致缓存数据不可用。结合移动网络下Web应用的特点，提出一种利用HTML5客户端持久化存储技术实现的Web客户端持久化缓存方案。所提出的缓存采用HTML5中LocalStorage作为底层的存储引擎，构建一个双向缓存，为Web应用客户端提供缓存对服务器读取及提交数据的服务，部分解决移动网络不稳定造成的用户无法读取及提交数据的问题；设计一种基于消息机制的自适应一致性同步策略用于缓存数据的同步，在尽可能保证数据一致性的前提下，分阶段提供不同一致性的数据窗口，，满足不同Web应用或操作对数据一致性以及响应时间的差异需求。在实验室自主研发论文分享系统中，基于所提出的Web客户端持久化缓存方案实现其移动客户端应用。对移动客户端测试结果表明，所提出的方案能解决突然断网的情况下客户端无法进行数据读取和提交操作问题；基于消息机制的自适应一致性同步策略让应用先使用缓存数据提供给用户，待更新到来时再更新缓存数据提供给用户；离线操作提交的数据先写入缓存后合并提交到服务器的策略，相比于运用浏览器缓存机制离线无法提交数据待在线重新分次提交的策略，请求次数由多次合并为单次，消除多次连接造成的时间开销，请求数据包由多个合并为单个，消除多个数据包头造成的带宽开销。
[Abstract]:Because of the low bandwidth, high delay, intermittent connectivity and other shortcomings of mobile network, Web users may have high response delay when they interact with the server to obtain or submit data through the mobile network, and even the Web services caused by sudden network interruption may not be available. Client-side caching technology is an effective way to solve the above problems, but the traditional browser caching mechanism has limitations in mobile network: (1) browser one-way caching can not cache the data submitted to the server. (2) the authentication mechanism requires that the browser must obtain the server verification result to read the cached data, and the sudden interruption of the network will cause the cache data to be unavailable. According to the characteristics of Web applications in mobile networks, a Web client persistence cache scheme based on HTML5 client persistence storage technology is proposed. The proposed cache uses Local Storage in HTML5 as the underlying storage engine to construct a bidirectional cache to provide Web application clients with the service of cache reading and submitting data to the server. It partly solves the problem that users can not read and submit data caused by the instability of mobile network, and designs an adaptive consistency synchronization strategy based on message mechanism for cache data synchronization, which can ensure data consistency as much as possible. Different consistent data windows are provided in stages to meet the different requirements of data consistency and response time for different Web applications or operations. In the thesis sharing system, the mobile client application is realized based on the Web client persistent cache scheme. The test results of mobile client show that the proposed scheme can solve the problem that the client can not read and submit data when the network is suddenly cut off. The adaptive consistency synchronization strategy based on message mechanism enables the application to provide the user with cached data first and then update the cache data to the user when the update arrives. The policy that the data submitted offline is written to the cache first and then merged to the server. Compared with the policy that the data can not be submitted online and resubmitted by using the browser caching mechanism, the number of requests is changed from multiple times to a single time. The time cost caused by multiple connections is eliminated, and the request packets are merged into a single packet, and the bandwidth overhead caused by multiple data packet headers is eliminated.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP333;TP393.09

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