# URL Helper

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

- Loading this Helper
- Available Functions

## Loading this Helper

This helper is loaded using the following code:

    $this->load->helper('url');

## Available Functions

The following functions are available:

`site_url`([$uri = ''[, $protocol = NULL]])

  Parameters: | $uri (string) – URI string $protocol (string) – Protocol, e.g. ‘http’ or ‘https’
  Returns: | Site URL
  Return type: | string

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

  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:

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

  This function is an alias for `CI_Config::site_url()`. For more info, please see the Config Library documentation.

`base_url`($uri = '', $protocol = NULL)

  Parameters: | $uri (string) – URI string $protocol (string) – Protocol, e.g. ‘http’ or ‘https’
  Returns: | Base URL
  Return type: | string

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

      echo base_url();

  This function returns the same thing as `site_url()`, without the index_page or url_suffix being appended.

  Also like `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 `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

  This function is an alias for `CI_Config::base_url()`. For more info, please see the Config Library documentation.

`current_url`()

  Returns: | The current URL
  Return type: | string

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

  Note

  Calling this function is the same as doing this: | | site_url(uri_string());

`uri_string`()

  Returns: | An URI string
  Return type: | string

  Returns the URI segments of any page that contains this function. For example, if your URL was this:

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

  The function would return:

      blog/comments/123

  This function is an alias for `CI_Config::uri_string()`. For more info, please see the Config Library documentation.

`index_page`()

  Returns: | ‘index_page’ value
  Return type: | mixed

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

      echo index_page();

`anchor`($uri = '', $title = '', $attributes = '')

  Parameters: | $uri (string) – URI string $title (string) – Anchor title $attributes (mixed) – HTML attributes
  Returns: | HTML hyperlink (anchor tag)
  Return type: | 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 `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', array('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">Click Here</a>

`anchor_popup`($uri = '', $title = '', $attributes = FALSE)

  Parameters: | $uri (string) – URI string $title (string) – Anchor title $attributes (mixed) – HTML attributes
  Returns: | Pop-up hyperlink
  Return type: | string

  Nearly identical to the `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 = array(
              '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!’, array());

  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.

`mailto`($email, $title = '', $attributes = '')

  Parameters: | $email (string) – E-mail address $title (string) – Anchor title $attributes (mixed) – HTML attributes
  Returns: | A “mail to” hyperlink
  Return type: | string

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

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

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

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

`safe_mailto`($email, $title = '', $attributes = '')

  Parameters: | $email (string) – E-mail address $title (string) – Anchor title $attributes (mixed) – HTML attributes
  Returns: | A spam-safe “mail to” hyperlink
  Return type: | string

  Identical to the `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.

`auto_link`($str, $type = 'both', $popup = FALSE)

  Parameters: | $str (string) – Input string $type (string) – Link type (‘email’, ‘url’ or ‘both’) $popup (bool) – Whether to create popup links
  Returns: | Linkified string
  Return type: | 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. Default behavior is both if the parameter is not specified. E-mail links are encoded as `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);

`url_title`($str, $separator = '-', $lowercase = FALSE)

  Parameters: | $str (string) – Input string $separator (string) – Word separator $lowercase (bool) – Whether to transform the output string to lower-case
  Returns: | URL-formatted string
  Return type: | 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

  Note

  Old usage of ‘dash’ and ‘underscore’ as the second parameter is DEPRECATED.

  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

`prep_url`($str = '')

  Parameters: | $str (string) – URL string
  Returns: | Protocol-prefixed URL string
  Return type: | 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');

`redirect`($uri = '', $method = 'auto', $code = NULL)

  Parameters: | $uri (string) – URI string $method (string) – Redirect method (‘auto’, ‘location’ or ‘refresh’) $code (string) – HTTP Response code (usually 302 or 303)
  Return type: | void

  Does a “header redirect” to the URI specified. If you specify the full site URL that link will be built, but for local links simply providing the URI segments to the controller you want to direct to will create the link. The function will build the URL based on your config file values.

  The optional second parameter allows you to force a particular redirection method. The available methods are auto, location and refresh, with location being faster but less reliable on IIS servers. The default is auto, which will attempt to intelligently choose the method based on the server environment.

  The optional third parameter allows you to send a specific HTTP Response Code - this could be used for example to create 301 redirects for search engine purposes. The default Response Code is 302. The third parameter is only available with location redirects, and not refresh. Examples:

      if ($logged_in == FALSE)
      {
              redirect('/login/form/');
      }

      // with 301 redirect
      redirect('/article/13', 'location', 301);

  Note

  In order for this function to work it must be used before anything is outputted to the browser since it utilizes server headers.

  Note

  For very fine grained control over headers, you should use the Output Library `set_header()` method.

  Note

  To IIS users: if you hide the Server HTTP header, the auto method won’t detect IIS, in that case it is advised you explicitly use the refresh method.

  Note

  When the location method is used, an HTTP status code of 303 will automatically be selected when the page is currently accessed via POST and HTTP/1.1 is used.

  Important

  This function will terminate script execution.