##########
URL Helper
##########

The URL Helper file contains functions that assist in working with URLs.

.. contents::
  :local:

.. raw:: html

  <div class="custom-index container"></div>

Loading this Helper
===================

This helper is automatically loaded by the framework on every request.

Available Functions
===================

The following functions are available:

.. php:function:: site_url([$uri = ''[, $protocol = NULL[, $altConfig = NULL]]])

	:param	mixed	$uri: URI string or array of URI segments
	:param	string	$protocol: Protocol, e.g. 'http' or 'https'
	:param	\\Config\\App	$altConfig: Alternate configuration to use
	:returns:	Site URL
	:rtype:	string

	Returns your site URL, as specified in your config file. The index.php
	file (or whatever you have set as your site **indexPage** in your config
	file) will be added to the URL, as will any URI segments you pass to the
	function.

	You are encouraged to use this function any time you need to generate a
	local URL so that your pages become more portable in the event your URL
	changes.

	Segments can be optionally passed to the function as a string or an
	array. Here is a string example::

		echo site_url('news/local/123');

	The above example would return something like:
	*http://example.com/index.php/news/local/123*

	Here is an example of segments passed as an array::

		$segments = ['news', 'local', '123'];
		echo site_url($segments);

        You may find the alternate configuration useful if generating URLs for a
        different site than yours, which contains different configuration preferences.
        We use this for unit testing the framework itself.

.. php:function:: base_url([$uri = ''[, $protocol = NULL]])

	:param	mixed	$uri: URI string or array of URI segments
	:param	string	$protocol: Protocol, e.g. 'http' or 'https'
	:returns:	Base URL
	:rtype:	string

	Returns your site base URL, as specified in your config file. Example::

		echo base_url();

	This function returns the same thing as :php:func:`site_url()`, without
	the *indexPage* being appended.

	Also like :php:func:`site_url()`, you can supply segments as a string or
	an array. Here is a string example::

		echo base_url("blog/post/123");

	The above example would return something like:
	*http://example.com/blog/post/123*

	This is useful because unlike :php:func:`site_url()`, you can supply a
	string to a file, such as an image or stylesheet. For example::

		echo base_url("images/icons/edit.png");

	This would give you something like:
	*http://example.com/images/icons/edit.png*

.. php:function:: current_url([$returnObject = false])

	:param	boolean	$returnObject: True if you would like a URI instance returned, instead of a string.
	:returns:	The current URL
	:rtype:	string|URI

	Returns the full URL (including segments) of the page being currently
	viewed.

	.. note:: Calling this function is the same as doing this::
		base_url(uri_string());

.. php:function:: previous_url([$returnObject = false])

	:param boolean $returnObject: True if you would like a URI instance returned instead of a string.
	:returns: The URL the user was previously on
	:rtype: string|URI

	Returns the full URL (including segments) of the page the user was previously on.

	Due to security issues of blindly trusting the HTTP_REFERER system variable, CodeIgniter will
	store previously visited pages in the session if it's available. This ensures that we always
	use a known and trusted source. If the session hasn't been loaded, or is otherwise unavailable,
	then a sanitized version of HTTP_REFERER will be used.

.. php:function:: uri_string()

	:returns:	An URI string
	:rtype:	string

	Returns the path part of your current URL.
	For example, if your URL was this::

		http://some-site.com/blog/comments/123

	The function would return::

		blog/comments/123

.. php:function:: index_page([$altConfig = NULL])

	:param	\Config\App	$altConfig: Alternate configuration to use
	:returns:	'index_page' value
	:rtype:	mixed

	Returns your site **indexPage**, as specified in your config file.
	Example::

		echo index_page();

        As with :php:func:`site_url()`, you may specify an alternate configuration.
        You may find the alternate configuration useful if generating URLs for a
        different site than yours, which contains different configuration preferences.
        We use this for unit testing the framework itself.

.. php:function:: anchor([$uri = ''[, $title = ''[, $attributes = ''[, $altConfig = NULL]]]])

	:param	mixed	$uri: URI string or array of URI segments
	:param	string	$title: Anchor title
	:param	mixed	$attributes: HTML attributes
	:param	\Config\App	$altConfig: Alternate configuration to use
	:returns:	HTML hyperlink (anchor tag)
	:rtype:	string

	Creates a standard HTML anchor link based on your local site URL.

	The first parameter can contain any segments you wish appended to the
	URL. As with the :php:func:`site_url()` function above, segments can
	be a string or an array.

	.. note:: If you are building links that are internal to your application
		do not include the base URL (http://...). This will be added
		automatically from the information specified in your config file.
		Include only the URI segments you wish appended to the URL.

	The second segment is the text you would like the link to say. If you
	leave it blank, the URL will be used.

	The third parameter can contain a list of attributes you would like
	added to the link. The attributes can be a simple string or an
	associative array.

	Here are some examples::

		echo anchor('news/local/123', 'My News', 'title="News title"');
		// Prints: <a href="http://example.com/index.php/news/local/123" title="News title">My News</a>

		echo anchor('news/local/123', 'My News', ['title' => 'The best news!']);
		// Prints: <a href="http://example.com/index.php/news/local/123" title="The best news!">My News</a>

		echo anchor('', 'Click here');
		// Prints: <a href="http://example.com/index.php">Click here</a>

	As above, you may specify an alternate configuration.
	You may find the alternate configuration useful if generating links for a
	different site than yours, which contains different configuration preferences.
	We use this for unit testing the framework itself.

	.. note:: Attributes passed into the anchor function are automatically escaped to protected against XSS attacks.

.. php:function:: anchor_popup([$uri = ''[, $title = ''[, $attributes = FALSE[, $altConfig = NULL]]]])

	:param	string	$uri: URI string
	:param	string	$title: Anchor title
	:param	mixed	$attributes: HTML attributes
	:param	\Config\App	$altConfig: Alternate configuration to use
	:returns:	Pop-up hyperlink
	:rtype:	string

	Nearly identical to the :php:func:`anchor()` function except that it
	opens the URL in a new window. You can specify JavaScript window
	attributes in the third parameter to control how the window is opened.
	If the third parameter is not set it will simply open a new window with
	your own browser settings.

	Here is an example with attributes::

		$atts = [
			'width'       => 800,
			'height'      => 600,
			'scrollbars'  => 'yes',
			'status'      => 'yes',
			'resizable'   => 'yes',
			'screenx'     => 0,
			'screeny'     => 0,
			'window_name' => '_blank'
		];

		echo anchor_popup('news/local/123', 'Click Me!', $atts);

	.. note:: The above attributes are the function defaults so you only need to
		set the ones that are different from what you need. If you want the
		function to use all of its defaults simply pass an empty array in the
		third parameter::

                    echo anchor_popup('news/local/123', 'Click Me!', []);

	.. note:: The **window_name** is not really an attribute, but an argument to
		the JavaScript `window.open() <http://www.w3schools.com/jsref/met_win_open.asp>`_
		method, which accepts either a window name or a window target.

	.. note:: Any other attribute than the listed above will be parsed as an
		HTML attribute to the anchor tag.

        As above, you may specify an alternate configuration.
        You may find the alternate configuration useful if generating links for a
        different site than yours, which contains different configuration preferences.
        We use this for unit testing the framework itself.

	.. note:: Attributes passed into the anchor_popup function are automatically escaped to protected against XSS attacks.

.. php:function:: mailto($email[, $title = ''[, $attributes = '']])

	:param	string	$email: E-mail address
	:param	string	$title: Anchor title
	:param	mixed	$attributes: HTML attributes
	:returns:	A "mail to" hyperlink
	:rtype:	string

	Creates a standard HTML e-mail link. Usage example::

		echo mailto('me@my-site.com', 'Click Here to Contact Me');

	As with the :php:func:`anchor()` tab above, you can set attributes using the
	third parameter::

		$attributes = ['title' => 'Mail me'];
		echo mailto('me@my-site.com', 'Contact Me', $attributes);

	.. note:: Attributes passed into the mailto function are automatically escaped to protected against XSS attacks.

.. php:function:: safe_mailto($email[, $title = ''[, $attributes = '']])

	:param	string	$email: E-mail address
	:param	string	$title: Anchor title
	:param	mixed	$attributes: HTML attributes
	:returns:	A spam-safe "mail to" hyperlink
	:rtype:	string

	Identical to the :php:func:`mailto()` function except it writes an obfuscated
	version of the *mailto* tag using ordinal numbers written with JavaScript to
	help prevent the e-mail address from being harvested by spam bots.

.. php:function:: auto_link($str[, $type = 'both'[, $popup = FALSE]])

	:param	string	$str: Input string
	:param	string	$type: Link type ('email', 'url' or 'both')
	:param	bool	$popup: Whether to create popup links
	:returns:	Linkified string
	:rtype:	string

	Automatically turns URLs and e-mail addresses contained in a string into
	links. Example::

		$string = auto_link($string);

	The second parameter determines whether URLs and e-mails are converted or
	just one or the other. The default behavior is both if the parameter is not
	specified. E-mail links are encoded as :php:func:`safe_mailto()` as shown
	above.

	Converts only URLs::

		$string = auto_link($string, 'url');

	Converts only e-mail addresses::

		$string = auto_link($string, 'email');

	The third parameter determines whether links are shown in a new window.
	The value can be TRUE or FALSE (boolean)::

		$string = auto_link($string, 'both', TRUE);

	.. note:: The only URLs recognized are those that start with "www." or with "://".

.. php:function:: url_title($str[, $separator = '-'[, $lowercase = FALSE]])

	:param	string	$str: Input string
	:param	string	$separator: Word separator
	:param	bool	$lowercase: Whether to transform the output string to lower-case
	:returns:	URL-formatted string
	:rtype:	string

	Takes a string as input and creates a human-friendly URL string. This is
	useful if, for example, you have a blog in which you'd like to use the
	title of your entries in the URL. Example::

		$title     = "What's wrong with CSS?";
		$url_title = url_title($title);
		// Produces: Whats-wrong-with-CSS

	The second parameter determines the word delimiter. By default dashes
	are used. Preferred options are: **-** (dash) or **_** (underscore).

	Example::

		$title     = "What's wrong with CSS?";
		$url_title = url_title($title, 'underscore');
		// Produces: Whats_wrong_with_CSS

	The third parameter determines whether or not lowercase characters are
	forced. By default they are not. Options are boolean TRUE/FALSE.

	Example::

		$title     = "What's wrong with CSS?";
		$url_title = url_title($title, 'underscore', TRUE);
		// Produces: whats_wrong_with_css

.. php:function:: prep_url($str = '')

	:param	string	$str: URL string
	:returns:	Protocol-prefixed URL string
	:rtype:	string

	This function will add *http://* in the event that a protocol prefix
	is missing from a URL.

	Pass the URL string to the function like this::

		$url = prep_url('example.com');
