stream_wrapper_register(protocol, classname) Registers a protocol; implementation is part of the class
The class implements standard functionality like reading, writing, or changing the file position.
php_user_filter is a predefined class in php and is used in conjunction with user-defined filters.
o Provide information on protocols and encodings
can be any file wrapper
allows for two pipelines at most – for reading & writing
o Prefix in front of a file path
file:// php://
http:// compress.zlib://
https:// compress.bzip2://
ftp:// ftps://
o Custom Wrappers
stream_wrapper_register(protocol, classname)
Registers a protocol; implementation is part of the class.
the class implements standard functionality like reading, writing, or changing the file position
php_user_filter is a predefined class in php and is used in conjunction with user-defined filters
stream_context_set_params — Set parameters for a stream/wrapper/context
Stream_context_get_options — Retrieve options for a stream/wrapper/context
Returns an array of options on the specified stream or context.
<?php
$params = array("method" => "POST");
stream_context_set_default(array("http" => $params));
echo '<pre>';print_r(stream_context_get_options(stream_context_get_default()));
?>
Stream_context_create — Creates a stream context.
Creates and returns a stream context with any options supplied in options preset.
<?php
$opts = array(
'http'=>array(
'method'=>"GET",
'header'=>"Accept-language: en\r\n" .
"Cookie: foo=bar\r\n"
)
);
$context = stream_context_create($opts);
$fp = fopen('http://www.phpcodez.com', 'r', false, $context);
fpassthru($fp);
fclose($fp);
?>
stream_get_meta_data — Retrieves header/meta data from streams/file pointers.
Returns information about an existing stream.
Example
<?php
$url = 'http://www.phpcodez.com/';
if (!$fp = fopen($url, 'r')) {
trigger_error("Unable to open URL ($url)", E_USER_ERROR);
}
$meta = stream_get_meta_data($fp);
echo "<pre>";print_r($meta);
fclose($fp);
?>
Streams are resources provided by PHP that we often use transparently, but which can also be very powerful tools. By learning how to harness their power, we can take our applications to a higher level.
Every stream has a implementation wrapper which has the additional code necessary to handle the specific protocol or encoding. PHP provides some built-in wrappers and we can easily create and register custom ones. We can even modify or enhance the behavior of wrappers using contexts and filters.
A context can modify or enhance the behavior of a stream
A context is a set of parameters and stream wrapper specific options
The following functions accepts a stream $context parameter.