Streams were introduced with PHP 4.3.0 as
a way of generalizing file, network, data compression, and other
operations which share a common set of functions and uses. In
its simplest definition, a
object which exhibits streamable
behavior. That is, it can be read from or written to in a linear
fashion, and may be able to
to an
arbitrary locations within the stream.
is additional code which tells the stream how to handle
specific protocols/encodings. For example, the
HTTP/1.0
request for a file on a remote server. There are many wrappers
built into PHP by default
and additional, custom wrappers may be added either within a
PHP script using
,
or directly from an extension using the API Reference.
Because any variety of wrapper may be added to PHP,
there is no set limit on what can be done with them. To access the list
of currently registered wrappers, use
.
(string) -
The name of the wrapper to be used. Examples include: file,
http, https, ftp, ftps, compress.zlib, compress.bz2, and php.If
no wrapper is specified, the function default is used (typically
://).
-
Depends on the wrapper used. For filesystem related streams this is
typically a path and filename of the desired file. For network related
streams this is typically a hostname, often with a path appended.