* @version 2.1.1 (last revision: July 15, 2013)
* @copyright (c) 2009 - 2013 Stefan Gabos
* @license http://www.gnu.org/licenses/lgpl-3.0.txt GNU LESSER GENERAL PUBLIC LICENSE
* @package Zebra_Pagination
*/
class Zebra_Pagination
{
// set defaults and initialize some private variables
private $_properties = array(
// should the "previous page" and "next page" links be always visible
'always_show_navigation' => true,
// should we avoid duplicate content
'avoid_duplicate_content' => true,
// default method for page propagation
'method' => 'get',
// string for "next page"
'next' => 'Next page',
// by default, prefix page number with zeroes
'padding' => true,
// the default starting page
'page' => 1,
// a flag telling whether current page was set manually or determined from the URL
'page_set' => false,
'navigation_position' => 'outside',
// a flag telling whether query strings in base_url should be kept or not
'preserve_query_string' => 0,
// string for "previous page"
'previous' => 'Previous page',
// by default, we assume there are no records
// we expect this number to be set after the class is instantiated
'records' => '',
// records per page
'records_per_page' => '',
// should the links be displayed in reverse order
'reverse' => false,
// number of selectable pages
'selectable_pages' => 11,
// will be computed later on
'total_pages' => 0,
// trailing slashes are added to generated URLs
// (when "method" is "url")
'trailing_slash' => true,
// this is the variable name to be used in the URL for propagating the page number
'variable_name' => 'page',
);
/**
* Constructor of the class.
*
* Initializes the class and the default properties.
*
* @return void
*/
function __construct()
{
// set the default base url
$this->base_url();
}
/**
* By default, the "previous page" and "next page" links are always shown.
*
* By disabling this feature the "previous page" and "next page" links will only be shown if there are more pages
* than set through {@link selectable_pages()}.
*
*
* // show "previous page" / "next page" only if there are more pages
* // than there are selectable pages
* $pagination->always_show_navigation(false);
*
*
* @param boolean $show (Optional) If set to FALSE, the "previous page" and "next page" links will only be
* shown if there are more pages than set through {@link selectable_pages()}.
*
* Default is TRUE.
*
* @since 2.0
*
* @return void
*/
public function always_show_navigation($show = true)
{
// set property
$this->_properties['always_show_navigation'] = $show;
}
/**
* When you first access a page with navigation you have the same content as you have when you access the first page
* from navigation. For example http://www.mywebsite.com/list will have the same content as http://www.mywebsite.com/list?page=1.
*
* From a search engine's point of view these are 2 distinct URLs having the same content and your pages will be
* penalized for that.
*
* So, by default, in order to avoid this, the library will have for the first page (or last, if you are displaying
* links in {@link reverse() reverse} order) the same path as you have for when you are accessing the page for the
* first (unpaginated) time.
*
* If you want to disable this behaviour call this method with its argument set to FALSE.
*
*
* // don't avoid duplicate content
* $pagination->avoid_duplicate_content(false);
*
*
* @param boolean $avoid_duplicate_content (Optional) If set to FALSE, the library will have for the first
* page (or last, if you are displaying links in {@link reverse() reverse}
* order) a different path than the one you have when you are accessing
* the page for the first (unpaginated) time.
*
* Default is TRUE.
*
* @return void
*
* @since 2.0
*/
function avoid_duplicate_content($avoid_duplicate_content = true)
{
// set property
$this->_properties['avoid_duplicate_content'] = $avoid_duplicate_content;
}
/**
* The base URL to be used when generating the navigation links.
*
* This is helpful for the case when, for example, the URL where the records are paginated may have parameters that
* are needed only once and need to be removed for any subsequent requests generated by pagination.
*
* For example, suppose some records are paginated at http://yourwebsite/mypage/. When a record from the list
* is updated, the URL could become something like http://youwebsite/mypage/?action=updated. Based on the
* value of action a message would be shown to the user.
*
* Because of the way this script works, the pagination links would become:
*
* - http://youwebsite/mypage/?action=updated&page=[page number] when {@link method()} is "get" and
* {@link variable_name()} is "page";
*
* - http://youwebsite/mypage/page[page number]/?action=updated when {@link method()} is "url" and
* {@link variable_name()} is "page").
*
* Because of this, whenever the user would paginate, the message would be shown to him again and again because
* action will be preserved in the URL!
*
* The solution is to set the base_url to http://youwebsite/mypage/ and in this way, regardless of
* however will the URL be changed, the pagination links will always be in the form of
*
* - http://youwebsite/mypage/?page=[page number] when {@link method()} is "get" and {@link variable_name()}
* is "page";
*
* - http://youwebsite/mypage/page[page number]/ when {@link method()} is "url" and {@link variable_name()} is "page").
*
* Of course, you may still have query strings in the value of the $base_url if you wish so, and these will be
* preserved when paginating.
*
* If you want to preserve the hash in the URL, make sure you load the zebra_pagination.js file!
*
* @param string $base_url (Optional) The base URL to be used when generating the navigation
* links
*
* Defaults is whatever returned by
* {@link http://www.php.net/manual/en/reserved.variables.server.php $_SERVER['REQUEST_URI']}
*
* @param boolean $preserve_query_string (Optional) Indicates whether values in query strings, other than
* those set in $base_url, should be preserved
*
* Default is TRUE
*
* @return void
*/
public function base_url($base_url = '', $preserve_query_string = true)
{
// set the base URL
$base_url = ($base_url == '' ? $_SERVER['REQUEST_URI'] : $base_url);
// parse the URL
$parsed_url = parse_url($base_url);
// cache the "path" part of the URL (that is, everything *before* the "?")
$this->_properties['base_url'] = $parsed_url['path'];
// cache the "query" part of the URL (that is, everything *after* the "?")
$this->_properties['base_url_query'] = isset($parsed_url['query']) ? $parsed_url['query'] : '';
// store query string as an associative array
parse_str($this->_properties['base_url_query'], $this->_properties['base_url_query']);
// should query strings (other than those set in $base_url) be preserved?
$this->_properties['preserve_query_string'] = $preserve_query_string;
}
/**
* Returns the current page's number.
*
*
* // echoes the current page
* echo $pagination->get_page();
*
*
* @return integer Returns the current page's number
*/
public function get_page()
{
// unless page was not specifically set through the "set_page" method
if (!$this->_properties['page_set']) {
// if
if (
// page propagation is SEO friendly
$this->_properties['method'] == 'url' &&
// the current page is set in the URL
preg_match('/\b' . preg_quote($this->_properties['variable_name']) . '([0-9]+)\b/i', $_SERVER['REQUEST_URI'], $matches) > 0
)
// set the current page to whatever it is indicated in the URL
$this->set_page((int)$matches[1]);
// if page propagation is done through GET and the current page is set in $_GET
elseif (isset($_GET[$this->_properties['variable_name']]))
// set the current page to whatever it was set to
$this->set_page((int)$_GET[$this->_properties['variable_name']]);
}
// if showing records in reverse order we must know the total number of records and the number of records per page
// *before* calling the "get_page" method
if ($this->_properties['reverse'] && $this->_properties['records'] == '') trigger_error('When showing records in reverse order you must specify the total number of records (by calling the "records" method) *before* the first use of the "get_page" method!', E_USER_ERROR);
if ($this->_properties['reverse'] && $this->_properties['records_per_page'] == '') trigger_error('When showing records in reverse order you must specify the number of records per page (by calling the "records_per_page" method) *before* the first use of the "get_page" method!', E_USER_ERROR);
// get the total number of pages
$this->_properties['total_pages'] = $this->get_pages();
// if there are any pages
if ($this->_properties['total_pages'] > 0) {
// if current page is beyond the total number pages
/// make the current page be the last page
if ($this->_properties['page'] > $this->_properties['total_pages']) $this->_properties['page'] = $this->_properties['total_pages'];
// if current page is smaller than 1
// make the current page 1
elseif ($this->_properties['page'] < 1) $this->_properties['page'] = 1;
}
// if we're just starting and we have to display links in reverse order
// set the first to the last one rather then first
if (!$this->_properties['page_set'] && $this->_properties['reverse']) $this->set_page($this->_properties['total_pages']);
// return the current page
return $this->_properties['page'];
}
/**
* Returns the total number of pages, based on the total number of records and the number of records to be shown
* per page.
*
*
* // get the total number of pages
* echo $pagination->get_pages();
*
*
* @since 2.1
*
* @return integer Returns the total number of pages, based on the total number of records and the number of
* records to be shown per page.
*/
public function get_pages()
{
// return the total number of pages based on the total number of records and number of records to be shown per page
return @ceil($this->_properties['records'] / $this->_properties['records_per_page']);
}
/**
* Change the labels for the "previous page" and "next page" links.
*
*
* // change the default labels
* $pagination->labels('Previous', 'Next');
*
*
* @param string $previous (Optional) The label for the "previous page" link.
*
* Default is "Previous page".
*
* @param string $next (Optional) The label for the "next page" link.
*
* Default is "Next page".
* @return void
*
* @since 2.0
*/
public function labels($previous = 'Previous page', $next = 'Next page')
{
// set the labels
$this->_properties['previous'] = $previous;
$this->_properties['next'] = $next;
}
/**
* Set the method to be used for page propagation.
*
*
* // set the method to the SEO friendly way
* $pagination->method('url');
*
*
* @param string $method (Optional) The method to be used for page propagation.
*
* Values can be:
*
* - url - page propagation is done in a SEO friendly way;
*
* This method requires the {@link http://httpd.apache.org/docs/current/mod/mod_rewrite.html mod_rewrite}
* module to be enabled on your Apache server (or the equivalent for other web servers);
*
* When using this method, the current page will be passed in the URL as
* http://youwebsite.com/yourpage/[variable name][page number]/ where
* [variable name] is set by {@link variable_name()} and [page number]
* represents the current page.
*
* - get - page propagation is done through GET;
*
* When using this method, the current page will be passed in the URL as
* http://youwebsite.com/yourpage?[variable name]=[page number] where
* [variable name] is set by {@link variable_name()} and [page number]
* represents the current page.
*
* Default is "get".
*
* @returns void
*/
public function method($method = 'get')
{
// set the page propagation method
$this->_properties['method'] = (strtolower($method) == 'url' ? 'url' : 'get') ;
}
/**
* By default, next/previous page links are shown on the outside of the links to individual pages.
*
* These links can also be shown both on the left or on the right of the links to individual pages by setting the
* method's argument to "left" or "right" respectively.
*
* @param string $position Setting this argument to "left" or "right" will instruct the script to show next/previous
* page links on the left or on the right of the links to individual pages.
*
* Allowed values are "left", "right" and "outside".
*
* Default is "outside".
*
* @since 2.1
*
* @return void
*/
function navigation_position($position)
{
// set the positioning of next/previous page links
$this->_properties['navigation_position'] = (in_array(strtolower($position), array('left', 'right')) ? strtolower($position) : 'outside') ;
}
/**
* Sets whether page numbers should be prefixed by zeroes.
*
* This is useful to keep the layout consistent by having the same number of characters for each page number.
*
*
* // disable padding numbers with zeroes
* $pagination->padding(false);
*
*
* @param boolean $enabled (Optional) Setting this property to FALSE will disable padding rather than
* enabling it.
*
* Default is TRUE.
*
* @return void
*/
public function padding($enabled = true)
{
// set padding
$this->_properties['padding'] = $enabled;
}
/**
* Sets the total number of records that need to be paginated.
*
* Based on this and on the value of {@link records_per_page()}, the script will know how many pages there are.
*
* The total number of pages is given by the fraction between the total number records (set through {@link records()})
* and the number of records that are shown on a page (set through {@link records_per_page()}).
*
*
* // tell the script that there are 100 total records
* $pagination->records(100);
*
*
* @param integer $records The total number of records that need to be paginated
*
* @return void
*/
public function records($records)
{
// the number of records
// make sure we save it as an integer
$this->_properties['records'] = (int)$records;
}
/**
* Sets the number of records that are displayed on one page.
*
* Based on this and on the value of {@link records()}, the script will know how many pages there are: the total
* number of pages is given by the fraction between the total number of records and the number of records that are
* shown on one page.
*
*
* // tell the class that there are 20 records displayed on one page
* $pagination->records_per_page(20);
*
*
* @param integer $records_per_page The number of records displayed on one page.
*
* Default is 10.
*
* @return void
*/
public function records_per_page($records_per_page)
{
// the number of records displayed on one page
// make sure we save it as an integer
$this->_properties['records_per_page'] = (int)$records_per_page;
}
/**
* Generates the output.
*
* Make sure your script references the CSS file!
*
*
* // generate output but don't echo it
* // but return it instead
* $output = $pagination->render(true);
*
*
* @param boolean $return_output (Optional) Setting this argument to TRUE will instruct the script to
* return the generated output rather than outputting it to the screen.
*
* Default is FALSE.
*
* @return void
*/
public function render($return_output = false)
{
// get some properties of the class
$this->get_page();
// if there is a single page, or no pages at all, don't display anything
if ($this->_properties['total_pages'] <= 1) return '';
// start building output
$output = '
* // show pagination links in reverse order rather than in natural order
* $pagination->reverse(true);
*
*
* @param boolean $reverse (Optional) Set it to TRUE to generate navigation links in reverse order.
*
* Default is FALSE.
*
* @return void
*
* @since 2.0
*/
public function reverse($reverse = false)
{
// set how the pagination links should be generated
$this->_properties['reverse'] = $reverse;
}
/**
* Sets the number of links to be displayed at once (besides the "previous page" and "next page" links)
*
*
* // display links to 15 pages
* $pagination->selectable_pages(15);
*
*
* @param integer $selectable_pages The number of links to be displayed at once (besides the "previous page"
* and "next page" links).
*
* You should set this to an odd number so that the same number of links
* will be shown to the left and to the right of the current page.
*
* Default is 11.
*
* @return void
*/
public function selectable_pages($selectable_pages)
{
// the number of selectable pages
// make sure we save it as an integer
$this->_properties['selectable_pages'] = (int)$selectable_pages;
}
/**
* Sets the current page.
*
*
* // sets the fifth page as the current page
* $pagination->set_page(5);
*
*
* @param integer $page The page's number.
*
* A number lower than 1 will be interpreted as 1, while a number
* greater than the total number of pages will be interpreted as the last page.
*
* The total number of pages is given by the fraction between the total number
* records (set through {@link records()}) and the number of records that are
* shown on one page (set through {@link records_per_page()}).
*
* @return void
*/
public function set_page($page)
{
// set the current page
// make sure we save it as an integer
$this->_properties['page'] = (int)$page;
// if the number is lower than one
// make it '1'
if ($this->_properties['page'] < 1) $this->_properties['page'] = 1;
// set a flag so that the "get_page" method doesn't change this value
$this->_properties['page_set'] = true;
}
/**
* Enables or disabled trailing slash on the generated URLs when {@link method} is "url".
*
* Read more on the subject on {@link http://googlewebmastercentral.blogspot.com/2010/04/to-slash-or-not-to-slash.html Google Webmasters's official blog}.
*
*
* // disables trailing slashes on generated URLs
* $pagination->trailing_slash(false);
*
*
* @param boolean $enabled (Optional) Setting this property to FALSE will disable trailing slashes on generated
* URLs when {@link method} is "url".
*
* Default is TRUE (trailing slashes are enabled by default).
*
* @return void
*/
public function trailing_slash($enabled)
{
// set the state of trailing slashes
$this->_properties['trailing_slash'] = $enabled;
}
/**
* Sets the variable name to be used for page propagation.
*
*
* // sets the variable name to "foo"
* // now, in the URL, the current page will be passed either as "foo=[page number]" (if method is "get") or
* // as "/foo[page number]" (if method is "url")
* $pagination->variable_name('foo');
*
*
* @param string $variable_name A string representing the variable name to be used for page propagation.
*
* Default is "page".
*
* @return void
*/
public function variable_name($variable_name)
{
// set the variable name
$this->_properties['variable_name'] = strtolower($variable_name);
}
/**
* Generate the link for the page given as argument.
*
* @access private
*
* @return void
*/
private function _build_uri($page)
{
// if page propagation method is through SEO friendly URLs
if ($this->_properties['method'] == 'url') {
// see if the current page is already set in the URL
if (preg_match('/\b' . $this->_properties['variable_name'] . '([0-9]+)\b/i', $this->_properties['base_url'], $matches) > 0) {
// build string
$url = str_replace('//', '/', preg_replace(
// replace the currently existing value
'/\b' . $this->_properties['variable_name'] . '([0-9]+)\b/i',
// if on the first page, remove it in order to avoid duplicate content
($page == 1 ? '' : $this->_properties['variable_name'] . $page),
$this->_properties['base_url']
));
// if the current page is not yet in the URL, set it, unless we're on the first page
// case in which we don't set it in order to avoid duplicate content
} else $url = rtrim($this->_properties['base_url'], '/') . '/' . ($this->_properties['variable_name'] . $page);
// handle trailing slash according to preferences
$url = rtrim($url, '/') . ($this->_properties['trailing_slash'] ? '/' : '');
// if values in the query string - other than those set through base_url() - are not to be preserved
// preserve only those set initially
if (!$this->_properties['preserve_query_string']) $query = implode('&', $this->_properties['base_url_query']);
// otherwise, get the current query string
else $query = $_SERVER['QUERY_STRING'];
// return the built string also appending the query string, if any
return $url . ($query != '' ? '?' . $query : '');
// if page propagation is to be done through GET
} else {
// if values in the query string - other than those set through base_url() - are not to be preserved
// preserve only those set initially
if (!$this->_properties['preserve_query_string']) $query = $this->_properties['base_url_query'];
// otherwise, get the current query string, if any, and transform it to an array
else parse_str($_SERVER['QUERY_STRING'], $query);
// if we are avoiding duplicate content and if not the first/last page (depending on whether the pagination links are shown in natural or reversed order)
if (!$this->_properties['avoid_duplicate_content'] || ($page != ($this->_properties['reverse'] ? $this->_properties['total_pages'] : 1)))
// add/update the page number
$query[$this->_properties['variable_name']] = $page;
// if we are avoiding duplicate content, don't use the "page" variable on the first/last page
elseif ($this->_properties['avoid_duplicate_content'] && $page == ($this->_properties['reverse'] ? $this->_properties['total_pages'] : 1))
unset($query[$this->_properties['variable_name']]);
// make sure the returned HTML is W3C compliant
return htmlspecialchars(html_entity_decode($this->_properties['base_url']) . (!empty($query) ? '?' . urldecode(http_build_query($query)) : ''));
}
}
/**
* Generates the "next page" link, depending on whether the pagination links are shown in natural or reversed order.
*
* @access private
*/
private function _show_next()
{
$output = '';
// if "always_show_navigation" is TRUE or
// if the total number of available pages is greater than the number of pages to be displayed at once
// it means we can show the "next page" link
if ($this->_properties['always_show_navigation'] || $this->_properties['total_pages'] > $this->_properties['selectable_pages'])
$output = '