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/**
* TfishMetadata class file.
*
* @copyright Simon Wilkinson 2013-2017 (https://tuskfish.biz)
* @license https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html GNU General Public License (GPL) V2
* @author Simon Wilkinson <[email protected]>
* @version Release: 1.0
* @since 1.0
* @package content
*/
// Enable strict type declaration.
declare(strict_types=1);
if (!defined("TFISH_ROOT_PATH")) die("TFISH_ERROR_ROOT_PATH_NOT_DEFINED");
/**
* Holds page-level metadata and generates pagination controls.
*
* Generates metadata for the page and pagination control. User-facing controller scripts can
* override the site-level defaults by uncommenting the options at the bottom of each file. A good
* example of this is when viewing a single content object; if it has the meta_title and
* meta_description fields set you can assign those to this object in order to customise the page
* title and description to the object, thereby improving your SEO.
*
* @copyright Simon Wilkinson 2013-2017 (https://tuskfish.biz)
* @license https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html GNU General Public License (GPL) V2
* @author Simon Wilkinson <[email protected]>
* @version Release: 1.0
* @since 1.0
* @package content
* @property string $title Meta title of this website.
* @property string $description Meta description of this website.
* @property string $author Author of this website.
* @property string $copyright Copyright notice.
* @property string $generator Software system that generated this page.
* @property string $seo SEO optimisation string to append to page URL.
* @property string $robots Meta instructions to robots.
* @property int $pagination_elements Number of slots in the pagination control.
*/
class TfishMetadata
{
/** @var object $preference Instance of TfishPreference class, holds site preference info. */
private $preference;
/** @var array $__data Array holding values of this object properties, accessed via magic methods. */
protected $__data = array(
'title' => '',
'description' => '',
'author' => '',
'copyright' => '',
'generator' => '',
'seo' => '',
'robots' => '',
'pagination_elements' => '');
/** Initialise object properties and default values.
*
* @param TfishPreference $preference Instance of TfishPreference, holding site preferences.
*/
function __construct(TfishPreference $preference)
{
$this->title = $preference->site_name;
$this->description = $preference->site_description;
$this->author = $preference->site_author;
$this->copyright = $preference->site_copyright;
$this->generator = 'Tuskfish CMS';
$this->seo = '';
$this->robots = 'index,follow';
$this->pagination_elements = $preference->pagination_elements;
}
/**
* Creates a pagination control designed for use with the Bootstrap framework.
*
* $query is an array of arbitrary query string parameters. Note that these need to be passed
* in as an array of key => value pairs, and you should build this yourself using known and
* whitelisted values. Do not pass through random query strings someone gave you on the
* internetz.
*
* If you want to create pagination controls for other presentation-side libraries add
* additional methods to this class.
*
* @param int $count Number of content objects (pages) matching these parameters.
* @param int $limit Number of content objects to retrieve in current view.
* @param string $url Target base URL for pagination control links.
* @param int $start Position in result set to retrieve content objects from.
* @param int $tag ID of tag used to filter content.
* @param array $extra_params Query string to be appended to the URLs (control script params).
* @return string HTML pagination control.
*/
public function getPaginationControl(int $count, int $limit, string $url, int $start = 0,
int $tag = 0, array $extra_params = array())
{
// Filter parameters.
$clean_count = TfishFilter::isInt($count, 1) ? (int) $count : 0;
$clean_limit = TfishFilter::isInt($limit, 1) ? (int) $limit : 0;
$clean_start = TfishFilter::isInt($start, 0) ? (int) $start : 0;
$clean_url = TfishFilter::isAlnumUnderscore($url) ? TfishFilter::trimString($url)
. '.php' : TFISH_URL;
$clean_tag = TfishFilter::isInt($tag) ? (int) $tag : 0;
// $extra_params is a potential XSS attack vector.
// The key => value pairs be i) rawurlencoded and ii) entity escaped. However, in order to
// avoid messing up the query and avoid unecessary decoding it is possible to maintain
// manual control over the operators. (Basically, input requiring encoding or escaping is
// absolutely not wanted here, it is just being conducted to mitigate XSS attacks). If you
// actually *want* to use such input you will need to decode it prior to use on the
// landing page.
$clean_extra_params = array();
foreach ($extra_params as $key => $value) {
// Check for directory traversals and null byte injection.
if (TfishFilter::hasTraversalorNullByte($key)
|| TfishFilter::hasTraversalorNullByte((string) $value)) {
trigger_error(TFISH_ERROR_TRAVERSAL_OR_NULL_BYTE, E_USER_ERROR);
return false;
}
$clean_extra_params[] = TfishFilter::encodeEscapeUrl($key) . '='
. TfishFilter::encodeEscapeUrl((string) $value);
unset($key, $value);
}
$clean_extra_params = !empty($clean_extra_params)
? TfishFilter::escape(implode("&", $clean_extra_params)) : '';
// If the count is zero there is no need for a pagination control.
if ($clean_count === 0) {
return false;
}
// If any parameter fails a range check throw an error.
if ($clean_limit === false || $clean_url === false) {
trigger_error(TFISH_ERROR_PAGINATION_PARAMETER_ERROR, E_USER_ERROR);
}
$control = $this->_getPavigationControl($clean_count, $clean_limit, $clean_url,
$clean_start, $clean_tag, $clean_extra_params);
return $control;
}
/** @internal */
private function _getPavigationControl(int $count, int $limit, string $url, int $start,
int $tag, string $extra_params)
{
// 1. Calculate number of pages, page number of start object and adjust for remainders.
$page_slots = array();
$page_count = (int) (($count / $limit));
$remainder = $count % $limit;
if ($remainder) {
$page_count += 1;
}
$page_range = range(1, $page_count);
// No need for pagination control if only one page.
if ($page_count === 1) {
return false;
}
// 2. Calculate current page.
$current_page = (int) (($start / $limit) + 1);
// 3. Calculate length of pagination control (number of slots).
$elements = ($this->pagination_elements > $page_count)
? $page_count : $this->pagination_elements;
// 4. Calculate the fore offset and initial (pre-adjustment) starting position.
$offset_int = (int) (($elements - 1) / 2);
$offset_float = ($elements - 1) / 2;
$page_start = $current_page - $offset_int;
// 5. Check if fore exceeds bounds. If so, set start = 1 and extract the range.
$fore_boundcheck = $current_page - $offset_int;
// 6. Check if aft exceeds bounds. If so set start = $page_count - length.
$aft_boundcheck = ($current_page + $offset_float);
// This is the tricky bit - slicing a variable region out of the range.
if ($page_count === $elements) {
$page_slots = $page_range;
} elseif ($fore_boundcheck < 1) {
$page_slots = array_slice($page_range, 0, $elements, true);
} elseif ($aft_boundcheck >= $page_count) {
$page_start = $page_count - $elements;
$page_slots = array_slice($page_range, $page_start, $elements, true);
} else {
$page_slots = array_slice($page_range, ($page_start - 1), $elements, true);
}
// 7. Substitute in the 'first' and 'last' page elements and sort the array back into
// numerical order.
end($page_slots);
unset($page_slots[key($page_slots)]);
$page_slots[($page_count - 1)] = TFISH_PAGINATION_LAST;
reset($page_slots);
unset($page_slots[key($page_slots)]);
$page_slots[0] = TFISH_PAGINATION_FIRST;
ksort($page_slots);
// Construct a HTML pagination control.
$control = '<nav aria-label="Page navigation"><ul class="pagination">';
// Prepare the query string.
$query = $start_arg = $tag_arg = '';
foreach ($page_slots as $key => $slot) {
$start = (int) ($key * $limit);
// Set the arguments.
if ($start || $tag || $extra_params) {
$arg_array = array();
if (!empty($start)) {
$arg_array[] = 'start=' . $start;
}
if (!empty($tag)) {
$arg_array[] = 'tag_id=' . $tag;
}
if (!empty($extra_params)) {
$arg_array[] = $extra_params;
}
$query = '?' . implode('&', $arg_array);
}
if (($key + 1) === $current_page) {
$control .= '<li class="page-item active"><a class="page-link" href="' . $url
. $query . '">' . $slot . '</a></li>';
} else {
$control .= '<li class="page-item"><a class="page-link" href="' . $url . $query
. '">' . $slot . '</a></li>';
}
unset($query, $key, $slot);
}
$control .= '</ul></nav>';
return $control;
}
/**
* Access an existing property and escape it for output to browser.
*
* @param string $property Name of property.
* @return string|bool Value of preference escaped for display if set, otherwise false.
*
* Note that the ENT_QUOTES flag must be set on htmlspecialchars() as these properties are
* used within attributes of meta tags, so a double quote would cause breakage.
*/
public function __get(string $property)
{
$clean_property = TfishFilter::trimString($property);
if (isset($this->__data[$clean_property])) {
return htmlspecialchars((string) $this->__data[$clean_property], ENT_QUOTES, "UTF-8",
false);
} else {
return null;
}
}
/**
* Set an existing property.
*
* @param string $property Name of property.
* @param mixed $value Value to assign to property.
*
* Note that htmlspecialchars() should use the ENT_QUOTES flag, as most of these values are
* used within attributes of meta tags, and a double quote would break them.
*/
public function __set(string $property, $value)
{
$clean_property = TfishFilter::trimString($property);
// Check that property is whitelisted.
if (!isset($this->__data[$clean_property])) {
trigger_error(TFISH_ERROR_NO_SUCH_PROPERTY, E_USER_ERROR);
}
// Validate properties against expectations and business rules.
switch ($clean_property) {
case "title":
case "description":
case "author":
case "copyright":
case "generator":
case "seo":
case "robots":
$clean_value = TfishFilter::trimString($value);
$this->__data[$clean_property] = htmlspecialchars($clean_value, ENT_QUOTES,
"UTF-8", false);
break;
case "pagination_elements":
if (TfishFilter::isInt($value, 3)) {
$clean_value = (int) $value;
$this->__data[$clean_property] = $clean_value;
}
break;
}
}
/**
* Intercept isset() calls to correctly read object properties
*
* @param string $property Name of property.
* @return bool True if set, false if not.
*/
public function __isset(string $property)
{
$clean_property = TfishFilter::trimString($property);
if (isset($this->__data[$clean_property])) {
return true;
} else {
return false;
}
}
/**
* Intercept unset() calls to correctly unset object properties
*
* @param string $property Name of property.
* @return bool True on success, false on failure.
*/
public function __unset(string $property)
{
$clean_property = TfishFilter::trimString($property);
if (isset($this->__data[$clean_property])) {
unset($this->__data[$clean_property]);
return true;
} else {
return false;
}
}
}