▪︎A web cache is also called a proxy server-is a network entity that satisfies HTTP requests on the behalf of an origin web server.
▪︎The web cache has it's own disk storage and keeps copies of recently requested objects in this storage.
▪︎A user's browser can be configured so that all the user's HTTP requests are first directed to a web cache.
Example:
suppose a browser is requesting the object http://www.someschool.edu/campus.gif.
Here is what happens:
1)The browser establishes a TCP connection to the web cache and sends an HTTP request for the object to the web cache.
2)The web cache checks to see if it has a copy of the object stored locally. If it does, the web cache returns the objects with in an HTTP response message to the client browser.
3)If the web cache doesn't have the object, the web cache opens a TCP connection to the origin server, that is,to www.someschool.edu.The web cache then sends an HTTP request for the objects into the cache-to-server TCP connection.
4)After receiving this request,the origin server sends the object within an HTTP response to the web cache.
5)When the web cache receives the object,it stores a copy in its local storage and sends a copy,within an HTTP response message, to the client server (over the existing TCP connection between the client browser and the web cache)
Advantages:
▪︎Speeding up loading and minimizing system resources needed to load a page.
▪︎Reduce load on Web Servers and Database
▪︎Page downloads faster
Disadvantages:
▪︎As information is stored in cache, it make page the heavy.
▪︎Sometimes the updated information doesnot show as the cache is not updated
▪︎It'll often increase complexity of the application, because the cache should be altered when the result of the operation will no longer be the result cached.
