MyShaarli/application/LinkFilter.php

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<?php
/**
* Class LinkFilter.
*
* Perform search and filter operation on link data list.
*/
class LinkFilter
{
/**
* @var string permalinks.
*/
public static $FILTER_HASH = 'permalink';
/**
* @var string text search.
*/
public static $FILTER_TEXT = 'fulltext';
/**
* @var string tag filter.
*/
public static $FILTER_TAG = 'tags';
/**
* @var string filter by day.
*/
public static $FILTER_DAY = 'FILTER_DAY';
/**
* @var string Allowed characters for hashtags (regex syntax).
*/
public static $HASHTAG_CHARS = '\p{Pc}\p{N}\p{L}\p{Mn}';
/**
* @var array all available links.
*/
private $links;
/**
* @param array $links initialization.
*/
public function __construct($links)
{
$this->links = $links;
}
/**
* Filter links according to parameters.
*
* @param string $type Type of filter (eg. tags, permalink, etc.).
* @param mixed $request Filter content.
* @param bool $casesensitive Optional: Perform case sensitive filter if true.
* @param bool $privateonly Optional: Only returns private links if true.
*
* @return array filtered link list.
*/
public function filter($type, $request, $casesensitive = false, $privateonly = false)
{
switch($type) {
case self::$FILTER_HASH:
return $this->filterSmallHash($request);
case self::$FILTER_TAG | self::$FILTER_TEXT:
if (!empty($request)) {
$filtered = $this->links;
if (isset($request[0])) {
$filtered = $this->filterTags($request[0], $casesensitive, $privateonly);
}
if (isset($request[1])) {
$lf = new LinkFilter($filtered);
$filtered = $lf->filterFulltext($request[1], $privateonly);
}
return $filtered;
}
return $this->noFilter($privateonly);
case self::$FILTER_TEXT:
return $this->filterFulltext($request, $privateonly);
case self::$FILTER_TAG:
return $this->filterTags($request, $casesensitive, $privateonly);
case self::$FILTER_DAY:
return $this->filterDay($request);
default:
return $this->noFilter($privateonly);
}
}
/**
* Unknown filter, but handle private only.
*
* @param bool $privateonly returns private link only if true.
*
* @return array filtered links.
*/
private function noFilter($privateonly = false)
{
if (! $privateonly) {
krsort($this->links);
return $this->links;
}
$out = array();
foreach ($this->links as $value) {
if ($value['private']) {
$out[$value['linkdate']] = $value;
}
}
krsort($out);
return $out;
}
/**
* Returns the shaare corresponding to a smallHash.
*
* @param string $smallHash permalink hash.
*
* @return array $filtered array containing permalink data.
*
* @throws LinkNotFoundException if the smallhash doesn't match any link.
*/
private function filterSmallHash($smallHash)
{
$filtered = array();
foreach ($this->links as $l) {
if ($smallHash == smallHash($l['linkdate'])) {
// Yes, this is ugly and slow
$filtered[$l['linkdate']] = $l;
return $filtered;
}
}
if (empty($filtered)) {
throw new LinkNotFoundException();
}
return $filtered;
}
/**
* Returns the list of links corresponding to a full-text search
*
* Searches:
* - in the URLs, title and description;
* - are case-insensitive;
* - terms surrounded by quotes " are exact terms search.
* - terms starting with a dash - are excluded (except exact terms).
*
* Example:
* print_r($mydb->filterFulltext('hollandais'));
*
* mb_convert_case($val, MB_CASE_LOWER, 'UTF-8')
* - allows to perform searches on Unicode text
* - see https://github.com/shaarli/Shaarli/issues/75 for examples
*
* @param string $searchterms search query.
* @param bool $privateonly return only private links if true.
*
* @return array search results.
*/
private function filterFulltext($searchterms, $privateonly = false)
{
if (empty($searchterms)) {
return $this->links;
}
$filtered = array();
$search = mb_convert_case(html_entity_decode($searchterms), MB_CASE_LOWER, 'UTF-8');
$exactRegex = '/"([^"]+)"/';
// Retrieve exact search terms.
preg_match_all($exactRegex, $search, $exactSearch);
$exactSearch = array_values(array_filter($exactSearch[1]));
// Remove exact search terms to get AND terms search.
$explodedSearchAnd = explode(' ', trim(preg_replace($exactRegex, '', $search)));
$explodedSearchAnd = array_values(array_filter($explodedSearchAnd));
// Filter excluding terms and update andSearch.
$excludeSearch = array();
$andSearch = array();
foreach ($explodedSearchAnd as $needle) {
if ($needle[0] == '-' && strlen($needle) > 1) {
$excludeSearch[] = substr($needle, 1);
} else {
$andSearch[] = $needle;
}
}
$keys = array('title', 'description', 'url', 'tags');
// Iterate over every stored link.
foreach ($this->links as $link) {
// ignore non private links when 'privatonly' is on.
if (! $link['private'] && $privateonly === true) {
continue;
}
// Concatenate link fields to search across fields.
// Adds a '\' separator for exact search terms.
$content = '';
foreach ($keys as $key) {
$content .= mb_convert_case($link[$key], MB_CASE_LOWER, 'UTF-8') . '\\';
}
// Be optimistic
$found = true;
// First, we look for exact term search
for ($i = 0; $i < count($exactSearch) && $found; $i++) {
$found = strpos($content, $exactSearch[$i]) !== false;
}
// Iterate over keywords, if keyword is not found,
// no need to check for the others. We want all or nothing.
for ($i = 0; $i < count($andSearch) && $found; $i++) {
$found = strpos($content, $andSearch[$i]) !== false;
}
// Exclude terms.
for ($i = 0; $i < count($excludeSearch) && $found; $i++) {
$found = strpos($content, $excludeSearch[$i]) === false;
}
if ($found) {
$filtered[$link['linkdate']] = $link;
}
}
krsort($filtered);
return $filtered;
}
/**
* Returns the list of links associated with a given list of tags
*
* You can specify one or more tags, separated by space or a comma, e.g.
* print_r($mydb->filterTags('linux programming'));
*
* @param string $tags list of tags separated by commas or blank spaces.
* @param bool $casesensitive ignore case if false.
* @param bool $privateonly returns private links only.
*
* @return array filtered links.
*/
public function filterTags($tags, $casesensitive = false, $privateonly = false)
{
// Implode if array for clean up.
$tags = is_array($tags) ? trim(implode(' ', $tags)) : $tags;
if (empty($tags)) {
return $this->links;
}
$searchtags = self::tagsStrToArray($tags, $casesensitive);
$filtered = array();
if (empty($searchtags)) {
return $filtered;
}
foreach ($this->links as $link) {
// ignore non private links when 'privatonly' is on.
if (! $link['private'] && $privateonly === true) {
continue;
}
$linktags = self::tagsStrToArray($link['tags'], $casesensitive);
$found = true;
for ($i = 0 ; $i < count($searchtags) && $found; $i++) {
// Exclusive search, quit if tag found.
// Or, tag not found in the link, quit.
if (($searchtags[$i][0] == '-'
&& $this->searchTagAndHashTag(substr($searchtags[$i], 1), $linktags, $link['description']))
|| ($searchtags[$i][0] != '-')
&& ! $this->searchTagAndHashTag($searchtags[$i], $linktags, $link['description'])
) {
$found = false;
}
}
if ($found) {
$filtered[$link['linkdate']] = $link;
}
}
krsort($filtered);
return $filtered;
}
/**
* Returns the list of articles for a given day, chronologically sorted
*
* Day must be in the form 'YYYYMMDD' (e.g. '20120125'), e.g.
* print_r($mydb->filterDay('20120125'));
*
* @param string $day day to filter.
*
* @return array all link matching given day.
*
* @throws Exception if date format is invalid.
*/
public function filterDay($day)
{
if (! checkDateFormat('Ymd', $day)) {
throw new Exception('Invalid date format');
}
$filtered = array();
foreach ($this->links as $l) {
if (startsWith($l['linkdate'], $day)) {
$filtered[$l['linkdate']] = $l;
}
}
ksort($filtered);
return $filtered;
}
/**
* Check if a tag is found in the taglist, or as an hashtag in the link description.
*
* @param string $tag Tag to search.
* @param array $taglist List of tags for the current link.
* @param string $description Link description.
*
* @return bool True if found, false otherwise.
*/
protected function searchTagAndHashTag($tag, $taglist, $description)
{
if (in_array($tag, $taglist)) {
return true;
}
if (preg_match('/(^| )#'. $tag .'([^'. self::$HASHTAG_CHARS .']|$)/mui', $description) > 0) {
return true;
}
return false;
}
/**
* Convert a list of tags (str) to an array. Also
* - handle case sensitivity.
* - accepts spaces commas as separator.
*
* @param string $tags string containing a list of tags.
* @param bool $casesensitive will convert everything to lowercase if false.
*
* @return array filtered tags string.
*/
public static function tagsStrToArray($tags, $casesensitive)
{
// We use UTF-8 conversion to handle various graphemes (i.e. cyrillic, or greek)
$tagsOut = $casesensitive ? $tags : mb_convert_case($tags, MB_CASE_LOWER, 'UTF-8');
$tagsOut = str_replace(',', ' ', $tagsOut);
return array_values(array_filter(explode(' ', trim($tagsOut)), 'strlen'));
}
}
class LinkNotFoundException extends Exception
{
protected $message = 'The link you are trying to reach does not exist or has been deleted.';
}