application/LinkFilter.php

   1 <?php
   2
   3 /**
   4  * Class LinkFilter.
   5  *
   6  * Perform search and filter operation on link data list.
   7  */
   8 class LinkFilter
   9 {
  10     /**
  11      * @var string permalinks.
  12      */
  13     public static $FILTER_HASH   = 'permalink';
  14
  15     /**
  16      * @var string text search.
  17      */
  18     public static $FILTER_TEXT   = 'fulltext';
  19
  20     /**
  21      * @var string tag filter.
  22      */
  23     public static $FILTER_TAG    = 'tags';
  24
  25     /**
  26      * @var string filter by day.
  27      */
  28     public static $FILTER_DAY    = 'FILTER_DAY';
  29
  30     /**
  31      * @var string Allowed characters for hashtags (regex syntax).
  32      */
  33     public static $HASHTAG_CHARS = '\p{Pc}\p{N}\p{L}\p{Mn}';
  34
  35     /**
  36      * @var LinkDB all available links.
  37      */
  38     private $links;
  39
  40     /**
  41      * @param LinkDB $links initialization.
  42      */
  43     public function __construct($links)
  44     {
  45         $this->links = $links;
  46     }
  47
  48     /**
  49      * Filter links according to parameters.
  50      *
  51      * @param string $type          Type of filter (eg. tags, permalink, etc.).
  52      * @param mixed  $request       Filter content.
  53      * @param bool   $casesensitive Optional: Perform case sensitive filter if true.
  54      * @param string $visibility    Optional: return only all/private/public links
  55      *
  56      * @return array filtered link list.
  57      */
  58     public function filter($type, $request, $casesensitive = false, $visibility = 'all')
  59     {
  60         if (! in_array($visibility, ['all', 'public', 'private'])) {
  61             $visibility = 'all';
  62         }
  63
  64         switch($type) {
  65             case self::$FILTER_HASH:
  66                 return $this->filterSmallHash($request);
  67             case self::$FILTER_TAG | self::$FILTER_TEXT:
  68                 if (!empty($request)) {
  69                     $filtered = $this->links;
  70                     if (isset($request[0])) {
  71                         $filtered = $this->filterTags($request[0], $casesensitive, $visibility);
  72                     }
  73                     if (isset($request[1])) {
  74                         $lf = new LinkFilter($filtered);
  75                         $filtered = $lf->filterFulltext($request[1], $visibility);
  76                     }
  77                     return $filtered;
  78                 }
  79                 return $this->noFilter($visibility);
  80             case self::$FILTER_TEXT:
  81                 return $this->filterFulltext($request, $visibility);
  82             case self::$FILTER_TAG:
  83                 return $this->filterTags($request, $casesensitive, $visibility);
  84             case self::$FILTER_DAY:
  85                 return $this->filterDay($request);
  86             default:
  87                 return $this->noFilter($visibility);
  88         }
  89     }
  90
  91     /**
  92      * Unknown filter, but handle private only.
  93      *
  94      * @param string $visibility Optional: return only all/private/public links
  95      *
  96      * @return array filtered links.
  97      */
  98     private function noFilter($visibility = 'all')
  99     {
 100         if ($visibility === 'all') {
 101             return $this->links;
 102         }
 103
 104         $out = array();
 105         foreach ($this->links as $key => $value) {
 106             if ($value['private'] && $visibility === 'private') {
 107                 $out[$key] = $value;
 108             } else if (! $value['private'] && $visibility === 'public') {
 109                 $out[$key] = $value;
 110             }
 111         }
 112
 113         return $out;
 114     }
 115
 116     /**
 117      * Returns the shaare corresponding to a smallHash.
 118      *
 119      * @param string $smallHash permalink hash.
 120      *
 121      * @return array $filtered array containing permalink data.
 122      *
 123      * @throws LinkNotFoundException if the smallhash doesn't match any link.
 124      */
 125     private function filterSmallHash($smallHash)
 126     {
 127         $filtered = array();
 128         foreach ($this->links as $key => $l) {
 129             if ($smallHash == $l['shorturl']) {
 130                 // Yes, this is ugly and slow
 131                 $filtered[$key] = $l;
 132                 return $filtered;
 133             }
 134         }
 135
 136         if (empty($filtered)) {
 137             throw new LinkNotFoundException();
 138         }
 139
 140         return $filtered;
 141     }
 142
 143     /**
 144      * Returns the list of links corresponding to a full-text search
 145      *
 146      * Searches:
 147      *  - in the URLs, title and description;
 148      *  - are case-insensitive;
 149      *  - terms surrounded by quotes " are exact terms search.
 150      *  - terms starting with a dash - are excluded (except exact terms).
 151      *
 152      * Example:
 153      *    print_r($mydb->filterFulltext('hollandais'));
 154      *
 155      * mb_convert_case($val, MB_CASE_LOWER, 'UTF-8')
 156      *  - allows to perform searches on Unicode text
 157      *  - see https://github.com/shaarli/Shaarli/issues/75 for examples
 158      *
 159      * @param string $searchterms search query.
 160      * @param string $visibility Optional: return only all/private/public links.
 161      *
 162      * @return array search results.
 163      */
 164     private function filterFulltext($searchterms, $visibility = 'all')
 165     {
 166         if (empty($searchterms)) {
 167             return $this->noFilter($visibility);
 168         }
 169
 170         $filtered = array();
 171         $search = mb_convert_case(html_entity_decode($searchterms), MB_CASE_LOWER, 'UTF-8');
 172         $exactRegex = '/"([^"]+)"/';
 173         // Retrieve exact search terms.
 174         preg_match_all($exactRegex, $search, $exactSearch);
 175         $exactSearch = array_values(array_filter($exactSearch[1]));
 176
 177         // Remove exact search terms to get AND terms search.
 178         $explodedSearchAnd = explode(' ', trim(preg_replace($exactRegex, '', $search)));
 179         $explodedSearchAnd = array_values(array_filter($explodedSearchAnd));
 180
 181         // Filter excluding terms and update andSearch.
 182         $excludeSearch = array();
 183         $andSearch = array();
 184         foreach ($explodedSearchAnd as $needle) {
 185             if ($needle[0] == '-' && strlen($needle) > 1) {
 186                 $excludeSearch[] = substr($needle, 1);
 187             } else {
 188                 $andSearch[] = $needle;
 189             }
 190         }
 191
 192         $keys = array('title', 'description', 'url', 'tags');
 193
 194         // Iterate over every stored link.
 195         foreach ($this->links as $id => $link) {
 196
 197             // ignore non private links when 'privatonly' is on.
 198             if ($visibility !== 'all') {
 199                 if (! $link['private'] && $visibility === 'private') {
 200                     continue;
 201                 } else if ($link['private'] && $visibility === 'public') {
 202                     continue;
 203                 }
 204             }
 205
 206             // Concatenate link fields to search across fields.
 207             // Adds a '\' separator for exact search terms.
 208             $content = '';
 209             foreach ($keys as $key) {
 210                 $content .= mb_convert_case($link[$key], MB_CASE_LOWER, 'UTF-8') . '\\';
 211             }
 212
 213             // Be optimistic
 214             $found = true;
 215
 216             // First, we look for exact term search
 217             for ($i = 0; $i < count($exactSearch) && $found; $i++) {
 218                 $found = strpos($content, $exactSearch[$i]) !== false;
 219             }
 220
 221             // Iterate over keywords, if keyword is not found,
 222             // no need to check for the others. We want all or nothing.
 223             for ($i = 0; $i < count($andSearch) && $found; $i++) {
 224                 $found = strpos($content, $andSearch[$i]) !== false;
 225             }
 226
 227             // Exclude terms.
 228             for ($i = 0; $i < count($excludeSearch) && $found; $i++) {
 229                 $found = strpos($content, $excludeSearch[$i]) === false;
 230             }
 231
 232             if ($found) {
 233                 $filtered[$id] = $link;
 234             }
 235         }
 236
 237         return $filtered;
 238     }
 239
 240     /**
 241      * Returns the list of links associated with a given list of tags
 242      *
 243      * You can specify one or more tags, separated by space or a comma, e.g.
 244      *  print_r($mydb->filterTags('linux programming'));
 245      *
 246      * @param string $tags          list of tags separated by commas or blank spaces.
 247      * @param bool   $casesensitive ignore case if false.
 248      * @param string $visibility    Optional: return only all/private/public links.
 249      *
 250      * @return array filtered links.
 251      */
 252     public function filterTags($tags, $casesensitive = false, $visibility = 'all')
 253     {
 254         // Implode if array for clean up.
 255         $tags = is_array($tags) ? trim(implode(' ', $tags)) : $tags;
 256         if (empty($tags)) {
 257             return $this->noFilter($visibility);
 258         }
 259
 260         $searchtags = self::tagsStrToArray($tags, $casesensitive);
 261         $filtered = array();
 262         if (empty($searchtags)) {
 263             return $filtered;
 264         }
 265
 266         foreach ($this->links as $key => $link) {
 267             // ignore non private links when 'privatonly' is on.
 268             if ($visibility !== 'all') {
 269                 if (! $link['private'] && $visibility === 'private') {
 270                     continue;
 271                 } else if ($link['private'] && $visibility === 'public') {
 272                     continue;
 273                 }
 274             }
 275
 276             $linktags = self::tagsStrToArray($link['tags'], $casesensitive);
 277
 278             $found = true;
 279             for ($i = 0 ; $i < count($searchtags) && $found; $i++) {
 280                 // Exclusive search, quit if tag found.
 281                 // Or, tag not found in the link, quit.
 282                 if (($searchtags[$i][0] == '-'
 283                         && $this->searchTagAndHashTag(substr($searchtags[$i], 1), $linktags, $link['description']))
 284                     || ($searchtags[$i][0] != '-')
 285                         && ! $this->searchTagAndHashTag($searchtags[$i], $linktags, $link['description'])
 286                 ) {
 287                     $found = false;
 288                 }
 289             }
 290
 291             if ($found) {
 292                 $filtered[$key] = $link;
 293             }
 294         }
 295         return $filtered;
 296     }
 297
 298     /**
 299      * Returns the list of articles for a given day, chronologically sorted
 300      *
 301      * Day must be in the form 'YYYYMMDD' (e.g. '20120125'), e.g.
 302      *  print_r($mydb->filterDay('20120125'));
 303      *
 304      * @param string $day day to filter.
 305      *
 306      * @return array all link matching given day.
 307      *
 308      * @throws Exception if date format is invalid.
 309      */
 310     public function filterDay($day)
 311     {
 312         if (! checkDateFormat('Ymd', $day)) {
 313             throw new Exception('Invalid date format');
 314         }
 315
 316         $filtered = array();
 317         foreach ($this->links as $key => $l) {
 318             if ($l['created']->format('Ymd') == $day) {
 319                 $filtered[$key] = $l;
 320             }
 321         }
 322
 323         // sort by date ASC
 324         return array_reverse($filtered, true);
 325     }
 326
 327     /**
 328      * Check if a tag is found in the taglist, or as an hashtag in the link description.
 329      *
 330      * @param string $tag         Tag to search.
 331      * @param array  $taglist     List of tags for the current link.
 332      * @param string $description Link description.
 333      *
 334      * @return bool True if found, false otherwise.
 335      */
 336     protected function searchTagAndHashTag($tag, $taglist, $description)
 337     {
 338         if (in_array($tag, $taglist)) {
 339             return true;
 340         }
 341
 342         if (preg_match('/(^| )#'. $tag .'([^'. self::$HASHTAG_CHARS .']|$)/mui', $description) > 0) {
 343             return true;
 344         }
 345
 346         return false;
 347     }
 348
 349     /**
 350      * Convert a list of tags (str) to an array. Also
 351      * - handle case sensitivity.
 352      * - accepts spaces commas as separator.
 353      *
 354      * @param string $tags          string containing a list of tags.
 355      * @param bool   $casesensitive will convert everything to lowercase if false.
 356      *
 357      * @return array filtered tags string.
 358      */
 359     public static function tagsStrToArray($tags, $casesensitive)
 360     {
 361         // We use UTF-8 conversion to handle various graphemes (i.e. cyrillic, or greek)
 362         $tagsOut = $casesensitive ? $tags : mb_convert_case($tags, MB_CASE_LOWER, 'UTF-8');
 363         $tagsOut = str_replace(',', ' ', $tagsOut);
 364
 365         return preg_split('/\s+/', $tagsOut, -1, PREG_SPLIT_NO_EMPTY);
 366     }
 367 }
 368
 369 class LinkNotFoundException extends Exception
 370 {
 371     protected $message = 'The link you are trying to reach does not exist or has been deleted.';
 372 }