Zend_Uri is a component that aids in manipulating and validating Uniform Resource Identifiers (URIs). Zend_Uri exists primarily to service other components, such as Zend_Http_Client, but is also useful as a standalone utility.

URIs always begin with a scheme, followed by a colon. The construction of the many different schemes varies significantly. The Zend_Uri class provides a factory that returns a subclass of itself which specializes in each scheme. The subclass will be named Zend_Uri_<scheme>, where <scheme> is the scheme, lowercased with the first letter capitalized. An exception to this rule is HTTPS, which is also handled by Zend_Uri_Http.

Zend_Uri will build a new URI from scratch if only a scheme is passed to Zend_Uri::factory().

// To create a new URI from scratch, pass only the scheme.
$uri = Zend_Uri::factory('http');

// $uri instanceof Zend_Uri_Http

To create a new URI from scratch, pass only the scheme to Zend_Uri::factory()^[31]. If an unsupported scheme is passed, a Zend_Uri_Exception will be thrown.

If the scheme or URI passed is supported, Zend_Uri::factory() will return a subclass of itself that specializes in the scheme to be created.

To manipulate an existing URI, pass the entire URI to Zend_Uri::factory().

// To manipulate an existing URI, pass it in.
$uri = Zend_Uri::factory('http://www.zend.com');

// $uri instanceof Zend_Uri_Http

The URI will be parsed and validated. If it is found to be invalid, a Zend_Uri_Exception will be thrown immediately. Otherwise, Zend_Uri::factory() will return a subclass of itself that specializes in the scheme to be manipulated.

The Zend_Uri::check() method can only be used if validation of an existing URI is needed.

// Validate whether a given URI is well formed
$valid = Zend_Uri::check('http://uri.in.question');

// $valid is TRUE for a valid URI, or FALSE otherwise.

Zend_Uri::check() returns a boolean, which is more convenient than using Zend_Uri::factory() and catching the exception.

73.1.4.1. Allowing "Unwise" characters in URIs

By default, Zend_Uri will not accept the following characters: "{", "}", "|", "\", "^", "`". These characters are defined by the RFC as "unwise" and invalid; however, many implementations do accept these characters as valid.

Zend_Uri can be set to accept these "unwise" characters by setting the 'allow_unwise' option to boolean TRUE using Zend_Uri::setConfig():

Ejemplo 73.4. Allowing special characters in URIs

// Contains '|' symbol
// Normally, this would return false:
$valid = Zend_Uri::check('http://example.com/?q=this|that');

// However, you can allow "unwise" characters
Zend_Uri::setConfig(array('allow_unwise' => true));

// will return 'true'
$valid = Zend_Uri::check('http://example.com/?q=this|that');

// Reset the 'allow_unwise' value to the default FALSE
Zend_Uri::setConfig(array('allow_unwise' => false));

	Nota
	Zend_Uri::setConfig() sets configuration options globally. It is recommended to reset the 'allow_unwise' option to 'FALSE', like in the example above, unless you are certain you want to always allow unwise characters globally.

Every instance of a Zend_Uri subclass (e.g. Zend_Uri_Http) has several instance methods that are useful for working with any kind of URI.

$uri = Zend_Uri::factory('http://www.zend.com');

$scheme = $uri->getScheme();  // "http"

$uri = Zend_Uri::factory('http://www.zend.com');

echo $uri->getUri();  // "http://www.zend.com"

$uri = Zend_Uri::factory('http://www.zend.com');

$isValid = $uri->valid();  // TRUE