ZEND PHP 5 Certification STUDY GUIDE

248 ” Streams and Network Programming
include(); for example, the following is perfectly valid (depending on your configuration):
include ’http://phparch.com’;
This capability is, of course, something that you should both love and fear: on one
hand, it allows you include remote files from a different server. On the other, it represents
a potential security hole of monumental proportions if the wrong person gets
their hands on your code.
Stream Contexts
Stream contexts allow you to pass options to the stream handlers that you transparently
use to access network resources, thus allowing you to tweak a handler’s behaviour
in ways that go beyond what normal file functionality can do. For example,
you can instruct the HTTP stream handler to perform a POST operation—which is
very handy when you want to work with Web services.
Stream contexts are created using stream_context_create():
$http_options = stream_context_create(array(
’http’ => array(
’user_agent’ => "Davey Shafiks Browser",
’max_redirects’ => 3
)
));
$file = file_get_contents("http://localhost/", false, $http_options);
In this example, we set context options for the http stream, providing our own custom
user agent string (which is always the polite thing to do to help people identify
the activity you perform on their server), and set the maximum number of transparent
redirections to three. Finally, as you can see, we pass the newly-created context
as a parameter to file_get_contents().
Licensed to 482634 - Amber Barrow (itsadmin@deakin.edu.au)
Advanced Stream Functionality
While the built-in stream handlers cover the most common network and file operations,
there are some instances—such as when dealing with custom proto-