Supported Protocols and Wrappers
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.