UserProviderInterface

Represents a class that loads UserInterface objects from some source for the authentication system.

In a typical authentication configuration, a username (i.e. some unique user identifier) credential enters the system (via form login, or any method). The user provider that is configured with that authentication method is asked to load the UserInterface object for the given username (via loadUserByUsername) so that the rest of the process can continue.

Internally, a user provider can load users from any source (databases, configuration, web service). This is totally independent of how the authentication information is submitted or what the UserInterface object looks like.