Research And Implementation Of Web Proxy Access Control Gateway System

As the explosive development of Internet, more and more people use it, at the same timethe amount of Internet informations become more and more huge. This leads to networkcongestion increasingly serious and reduces the quality of network services. On the otherhand, the Internet is filled with a lot of bad informations, such as violence, antisocial,pornography. They are not only the corruption of social morality, but also seriously affect thehealthy growth of minors’ body and mind. Web proxy server is located at the network gateway,which can use web cache to speed up user accesses, and use blacklist and whitelist to controluser accesses. So these two problems described above can be solved by web proxy server.Therefore, how to improve the performance of both the web cache replacement algorithm andURL string matching algorithm is becoming more and more important.First of all, the paper improved Greedy Dual-Size cache replacement algorithm by takinginto account the spatial locality and popularity of web object. The Greedy Dual-Sizealgorithm takes both the size and the temporal locality of web object and the cost of accessesabout the web object into considering, in order to calculate the cache value of the web object.When the cache value of multiple web objects is equal, the Greedy Dual-Size algorithm mayreplace the more popular and closely web object. For this case, the paper used the spatiallocality and the popularity of web object to improve the Greedy Dual-Size algorithm. Theexperimental results showed that the improved Greedy Dual-Size algorithm improved the hitrate and byte hit rate, reduced access latency rate.Second, the paper improved Hash_WB_Like string matching algorithm by taking intoaccount the user access behavior distribution characteristics. According to the situation that alarge number of user access URL match blacklist failed, the paper using the bitmap method toimprove Hash_WB_Like algorithm, so as to avoid the amont most of the URL matchoperation on the bucket list. Then the method stores the URL which the user often accessedinto the whitelist and uses the whitelist to filter URL to reduce the number of matches in theblacklist. What is more, the capacity of whitelist is much smaller than blacklist. Theexperimental results showed that the improved Hash_WB_Like algorithm improved the URLstring match performance.Finally, it achieved a gateway system of access control. The system applied the improved Greedy Dual-Size algorithm in web cache replacement and used the improved Hash-WB-Likealgorithm into URL filtering. It described the design and implementation of the systemmodules, and tested the function and performance of the system.