URL Rewriting

URL Rewriting is a technique of masking the dynamic URLs with static URLs. Dynamic URLs are URLs which contain variables in it. A typical dynamic URL might look like http://www.dynamicurl.com/index.asp?id=1&subid=2&catid=3. Here, id, subid and catid are URL variables. Technically, these URL variables are called query strings. Dynamic URLs are unfriendly both for users and for the search engines. Dynamic URLs are considered unfriendly for following reasons

• Dynamic URLs are hard to read and remember. The punctuation and identifiers used makes it difficult for users to read and remember them. So, users can't normally easily guess the URLs of a page. It barely provides any clues to average users as to what a web page is about. Hence, Dynamic URLs have usability problem.
 
• Dynamic URLs provide lower level of abstraction and maintainability. Dynamic URLs exposes the underlying technology, hence are relatively more prone to attack by hackers. In Dynamic URLs we can easily see the technology used. For example, in above URL we can see that page is written using ASP and it passes number of query strings to alter the content of the page. Though for normal users it is almost impossible, an experienced hacker might well tamper with the pages, if programmer has not provided enough security. Moreover, Dynamic URLs are also difficult to maintain, hence chances of broken links is high.
 
• Dynamic URLs are not liked by Search Engines. Though most of the search engines claim that they index dynamic pages or dynamic URLs and some of them like Google do. But, not all search engines are sophisticated enough to do this. Even the sophisticated Search Engines might not index all of the dynamic URLs, they do so with limitations. It is because, the objectives of search engines is to provide relevant search results to any search term being queried. They also try to avoid duplicate content in a web page. So, normally when search engines encounter similar pattern of query strings or URL variables they might not index them being suspicious about duplicate content. Search Engines also have some limits of how many dynamic URLs they would index.

 

Hence, URL Rewriting techniques like URL Rewrite for windows using ISAPI filter and for apache using mod rewrite are inevitable for various reasons. The obvious Advantages of URL rewriting is

• Usability
• Security
• Search Engine Visibility

 

By using URL Rewriting techniques we convert the dynamic looking URL into static looking URL. For example,http://www.mydomain.com/details.asp?state=california&county=orange-county can be masked with static ones such as http://www.mydomain.com/details/california/orange-county/