# Glossary

component

  A part of a URL delimited by slashes. The URL “/help/about” contains two components: “help” and “about”.

generation

  The act of creating a URL based on a route name and/or variable values. This is the opposite of matching. Finding a route by name is called named generation. Finding a route without specifying a name is called nameless generation.

mapper

  A container for routes. There is normally one mapper per application, although nested subapplications might have their own mappers. A mapper knows how to match routes and generate them.

matching

  The act of matching a given URL against a list of routes, and returning the routing variables. See the route entry for an example.

minimization

  A deprecated feature which allowed short URLs to match long paths. Details are in the `Backward Compatibility` section in the manual.

route

  A rule mapping a URL pattern to a dict of routing variables. For instance, if the pattern is “/{controller}/{action}” and the requested URL is “/help/about”, the resulting dict would be:

      {"controller": "help", "action": "about"}

  Routes does not know what these variables mean; it simply returns them to the application. Pylons would look for a `controllers/help.py` module containing a `HelpController` class, and call its `about` method. Other frameworks may do something different.

  A route may have a name, used to identify the route.

route path

  The URL pattern in a route.

routing variables

  A dict of key-value pairs returned by matching. Variables defined in the route path are called path variables; their values will be taken from the URL. Variables defined outside the route path are called default variables; their values are not affected by the URL.

  The WSGI.org environment key for routing variables is “wsgiorg.routing_args”. This manual does not use that term because it can be confused with function arguments.