A framework's [[Uniform Resource Locator|URL]] mapping or routing facility is the mechanism by which the framework interprets URLs. Some frameworks, such as Drupal and Django, match the provided URL against pre-determined patterns using [[regular expression]]s, while some others use [[rewriting]] techniques to translate the provided URL into one that the underlying engine will recognize. Another technique is that of [[graph traversal]] such as used by [[Zope]], where a URL is decomposed in steps that traverse an object graph (of models and views).{{citation needed|date=January 2017}}
A URL mapping system that
A URL mapping system that uses pattern matching or rewriting to route and handle requests allows for [[URL shortening|shorter]] more "[[friendly URL]]s" to be used, increasing the simplicity of the site and allowing for better indexing by search engines. For example, a URL that ends with "/page.cgi?cat=science&topic=physics" could be changed to simply "/page/science/physics". This makes the URL easier for people to remember, read and write, and provides search engines with better information about the structural layout of the site. A graph traversal approach also tends to result in the creation of friendly URLs. A shorter URL such as "/page/science" tends to exist by default as that is simply a shorter form of the longer traversal to "/page/science/physics".{{citation needed|date=January 2017}}
