PHP comes with many built-in wrappers for various URL-style protocols
for use with the filesystem functions such as fopen(),
copy(), file_exists() and
filesize().
In addition to these wrappers, it is possible to register custom wrappers
using the stream_wrapper_register() function.
Note:
The URL syntax used to describe a wrapper only supports the
scheme://... syntax. The scheme:/
and scheme: syntaxes are not supported.