Gorilla/mux implements a request router and dispatcher.

the name mux stands for "http request multiplexer". like the standard http.servemux, mux.router matches incoming requests against a list of registered routes and calls a handler for the route that matches the url or other conditions. the main features are:

* requests can be matched based on url host, path, path prefix, schemes,
header and query values, http methods or using custom matchers.
* url hosts and paths can have variables with an optional regular
expression.
* registered urls can be built, or "reversed", which helps maintaining
references to resources.
* routes can be used as subrouters: nested routes are only tested if the
parent route matches. this is useful to define groups of routes that
share common conditions like a host, a path prefix or other repeated
attributes. as a bonus, this optimizes request matching.
* it implements the http.handler interface so it is compatible with the
standard http.servemux.