application/LinkDB.php

   1 <?php
   2 /**
   3  * Data storage for links.
   4  *
   5  * This object behaves like an associative array.
   6  *
   7  * Example:
   8  *    $myLinks = new LinkDB();
   9  *    echo $myLinks['20110826_161819']['title'];
  10  *    foreach ($myLinks as $link)
  11  *       echo $link['title'].' at url '.$link['url'].'; description:'.$link['description'];
  12  *
  13  * Available keys:
  14  *  - description: description of the entry
  15  *  - linkdate: date of the creation of this entry, in the form YYYYMMDD_HHMMSS
  16  *              (e.g.'20110914_192317')
  17  *  - private:  Is this link private? 0=no, other value=yes
  18  *  - tags:     tags attached to this entry (separated by spaces)
  19  *  - title     Title of the link
  20  *  - url       URL of the link. Can be absolute or relative.
  21  *              Relative URLs are permalinks (e.g.'?m-ukcw')
  22  *
  23  * Implements 3 interfaces:
  24  *  - ArrayAccess: behaves like an associative array;
  25  *  - Countable:   there is a count() method;
  26  *  - Iterator:    usable in foreach () loops.
  27  */
  28 class LinkDB implements Iterator, Countable, ArrayAccess
  29 {
  30     // Links are stored as a PHP serialized string
  31     private $datastore;
  32
  33     // Datastore PHP prefix
  34     protected static $phpPrefix = '<?php /* ';
  35
  36     // Datastore PHP suffix
  37     protected static $phpSuffix = ' */ ?>';
  38
  39     // List of links (associative array)
  40     //  - key:   link date (e.g. "20110823_124546"),
  41     //  - value: associative array (keys: title, description...)
  42     private $links;
  43
  44     // List of all recorded URLs (key=url, value=linkdate)
  45     // for fast reserve search (url-->linkdate)
  46     private $urls;
  47
  48     // List of linkdate keys (for the Iterator interface implementation)
  49     private $keys;
  50
  51     // Position in the $this->keys array (for the Iterator interface)
  52     private $position;
  53
  54     // Is the user logged in? (used to filter private links)
  55     private $loggedIn;
  56
  57     // Hide public links
  58     private $hidePublicLinks;
  59
  60     /**
  61      * Creates a new LinkDB
  62      *
  63      * Checks if the datastore exists; else, attempts to create a dummy one.
  64      *
  65      * @param $isLoggedIn is the user logged in?
  66      */
  67     function __construct($datastore, $isLoggedIn, $hidePublicLinks)
  68     {
  69         $this->datastore = $datastore;
  70         $this->loggedIn = $isLoggedIn;
  71         $this->hidePublicLinks = $hidePublicLinks;
  72         $this->checkDB();
  73         $this->readdb();
  74     }
  75
  76     /**
  77      * Countable - Counts elements of an object
  78      */
  79     public function count()
  80     {
  81         return count($this->links);
  82     }
  83
  84     /**
  85      * ArrayAccess - Assigns a value to the specified offset
  86      */
  87     public function offsetSet($offset, $value)
  88     {
  89         // TODO: use exceptions instead of "die"
  90         if (!$this->loggedIn) {
  91             die('You are not authorized to add a link.');
  92         }
  93         if (empty($value['linkdate']) || empty($value['url'])) {
  94             die('Internal Error: A link should always have a linkdate and URL.');
  95         }
  96         if (empty($offset)) {
  97             die('You must specify a key.');
  98         }
  99         $this->links[$offset] = $value;
 100         $this->urls[$value['url']]=$offset;
 101     }
 102
 103     /**
 104      * ArrayAccess - Whether or not an offset exists
 105      */
 106     public function offsetExists($offset)
 107     {
 108         return array_key_exists($offset, $this->links);
 109     }
 110
 111     /**
 112      * ArrayAccess - Unsets an offset
 113      */
 114     public function offsetUnset($offset)
 115     {
 116         if (!$this->loggedIn) {
 117             // TODO: raise an exception
 118             die('You are not authorized to delete a link.');
 119         }
 120         $url = $this->links[$offset]['url'];
 121         unset($this->urls[$url]);
 122         unset($this->links[$offset]);
 123     }
 124
 125     /**
 126      * ArrayAccess - Returns the value at specified offset
 127      */
 128     public function offsetGet($offset)
 129     {
 130         return isset($this->links[$offset]) ? $this->links[$offset] : null;
 131     }
 132
 133     /**
 134      * Iterator - Returns the current element
 135      */
 136     function current()
 137     {
 138         return $this->links[$this->keys[$this->position]];
 139     }
 140
 141     /**
 142      * Iterator - Returns the key of the current element
 143      */
 144     function key()
 145     {
 146         return $this->keys[$this->position];
 147     }
 148
 149     /**
 150      * Iterator - Moves forward to next element
 151      */
 152     function next()
 153     {
 154         ++$this->position;
 155     }
 156
 157     /**
 158      * Iterator - Rewinds the Iterator to the first element
 159      *
 160      * Entries are sorted by date (latest first)
 161      */
 162     function rewind()
 163     {
 164         $this->keys = array_keys($this->links);
 165         rsort($this->keys);
 166         $this->position = 0;
 167     }
 168
 169     /**
 170      * Iterator - Checks if current position is valid
 171      */
 172     function valid()
 173     {
 174         return isset($this->keys[$this->position]);
 175     }
 176
 177     /**
 178      * Checks if the DB directory and file exist
 179      *
 180      * If no DB file is found, creates a dummy DB.
 181      */
 182     private function checkDB()
 183     {
 184         if (file_exists($this->datastore)) {
 185             return;
 186         }
 187
 188         // Create a dummy database for example
 189         $this->links = array();
 190         $link = array(
 191             'title'=>'Shaarli - sebsauvage.net',
 192             'url'=>'http://sebsauvage.net/wiki/doku.php?id=php:shaarli',
 193             'description'=>'Welcome to Shaarli! This is a bookmark. To edit or delete me, you must first login.',
 194             'private'=>0,
 195             'linkdate'=>'20110914_190000',
 196             'tags'=>'opensource software'
 197         );
 198         $this->links[$link['linkdate']] = $link;
 199
 200         $link = array(
 201             'title'=>'My secret stuff... - Pastebin.com',
 202             'url'=>'http://sebsauvage.net/paste/?8434b27936c09649#bR7XsXhoTiLcqCpQbmOpBi3rq2zzQUC5hBI7ZT1O3x8=',
 203             'description'=>'SShhhh!!  I\'m a private link only YOU can see. You can delete me too.',
 204             'private'=>1,
 205             'linkdate'=>'20110914_074522',
 206             'tags'=>'secretstuff'
 207         );
 208         $this->links[$link['linkdate']] = $link;
 209
 210         // Write database to disk
 211         // TODO: raise an exception if the file is not write-able
 212         file_put_contents(
 213             $this->datastore,
 214             self::$phpPrefix.base64_encode(gzdeflate(serialize($this->links))).self::$phpSuffix
 215         );
 216     }
 217
 218     /**
 219      * Reads database from disk to memory
 220      */
 221     private function readdb()
 222     {
 223
 224         // Public links are hidden and user not logged in => nothing to show
 225         if ($this->hidePublicLinks && !$this->loggedIn) {
 226             $this->links = array();
 227             return;
 228         }
 229
 230         // Read data
 231         // Note that gzinflate is faster than gzuncompress.
 232         // See: http://www.php.net/manual/en/function.gzdeflate.php#96439
 233         $this->links = array();
 234
 235         if (file_exists($this->datastore)) {
 236             $this->links = unserialize(gzinflate(base64_decode(
 237                 substr(file_get_contents($this->datastore),
 238                        strlen(self::$phpPrefix), -strlen(self::$phpSuffix)))));
 239         }
 240
 241         // If user is not logged in, filter private links.
 242         if (!$this->loggedIn) {
 243             $toremove = array();
 244             foreach ($this->links as $link) {
 245                 if ($link['private'] != 0) {
 246                     $toremove[] = $link['linkdate'];
 247                 }
 248             }
 249             foreach ($toremove as $linkdate) {
 250                 unset($this->links[$linkdate]);
 251             }
 252         }
 253
 254         // Keep the list of the mapping URLs-->linkdate up-to-date.
 255         $this->urls = array();
 256         foreach ($this->links as $link) {
 257             $this->urls[$link['url']] = $link['linkdate'];
 258         }
 259
 260         // Escape links data
 261         foreach($this->links as &$link) {
 262             sanitizeLink($link);
 263         }
 264     }
 265
 266     /**
 267      * Saves the database from memory to disk
 268      */
 269     public function savedb()
 270     {
 271         if (!$this->loggedIn) {
 272             // TODO: raise an Exception instead
 273             die('You are not authorized to change the database.');
 274         }
 275         file_put_contents(
 276             $this->datastore,
 277             self::$phpPrefix.base64_encode(gzdeflate(serialize($this->links))).self::$phpSuffix
 278         );
 279         invalidateCaches();
 280     }
 281
 282     /**
 283      * Returns the link for a given URL, or False if it does not exist.
 284      */
 285     public function getLinkFromUrl($url)
 286     {
 287         if (isset($this->urls[$url])) {
 288             return $this->links[$this->urls[$url]];
 289         }
 290         return false;
 291     }
 292
 293     /**
 294      * Returns the list of links corresponding to a full-text search
 295      *
 296      * Searches:
 297      *  - in the URLs, title and description;
 298      *  - are case-insensitive.
 299      *
 300      * Example:
 301      *    print_r($mydb->filterFulltext('hollandais'));
 302      *
 303      * mb_convert_case($val, MB_CASE_LOWER, 'UTF-8')
 304      *  - allows to perform searches on Unicode text
 305      *  - see https://github.com/shaarli/Shaarli/issues/75 for examples
 306      */
 307     public function filterFulltext($searchterms)
 308     {
 309         // FIXME: explode(' ',$searchterms) and perform a AND search.
 310         // FIXME: accept double-quotes to search for a string "as is"?
 311         $filtered = array();
 312         $search = mb_convert_case($searchterms, MB_CASE_LOWER, 'UTF-8');
 313         $keys = array('title', 'description', 'url', 'tags');
 314
 315         foreach ($this->links as $link) {
 316             $found = false;
 317
 318             foreach ($keys as $key) {
 319                 if (strpos(mb_convert_case($link[$key], MB_CASE_LOWER, 'UTF-8'),
 320                            $search) !== false) {
 321                     $found = true;
 322                 }
 323             }
 324
 325             if ($found) {
 326                 $filtered[$link['linkdate']] = $link;
 327             }
 328         }
 329         krsort($filtered);
 330         return $filtered;
 331     }
 332
 333     /**
 334      * Returns the list of links associated with a given list of tags
 335      *
 336      * You can specify one or more tags, separated by space or a comma, e.g.
 337      *  print_r($mydb->filterTags('linux programming'));
 338      */
 339     public function filterTags($tags, $casesensitive=false)
 340     {
 341         // Same as above, we use UTF-8 conversion to handle various graphemes (i.e. cyrillic, or greek)
 342         // FIXME: is $casesensitive ever true?
 343         $t = str_replace(
 344             ',', ' ',
 345             ($casesensitive ? $tags : mb_convert_case($tags, MB_CASE_LOWER, 'UTF-8'))
 346         );
 347
 348         $searchtags = explode(' ', $t);
 349         $filtered = array();
 350
 351         foreach ($this->links as $l) {
 352             $linktags = explode(
 353                 ' ',
 354                 ($casesensitive ? $l['tags']:mb_convert_case($l['tags'], MB_CASE_LOWER, 'UTF-8'))
 355             );
 356
 357             if (count(array_intersect($linktags, $searchtags)) == count($searchtags)) {
 358                 $filtered[$l['linkdate']] = $l;
 359             }
 360         }
 361         krsort($filtered);
 362         return $filtered;
 363     }
 364
 365
 366     /**
 367      * Returns the list of articles for a given day, chronologically sorted
 368      *
 369      * Day must be in the form 'YYYYMMDD' (e.g. '20120125'), e.g.
 370      *  print_r($mydb->filterDay('20120125'));
 371      */
 372     public function filterDay($day)
 373     {
 374         // TODO: check input format
 375         $filtered = array();
 376         foreach ($this->links as $l) {
 377             if (startsWith($l['linkdate'], $day)) {
 378                 $filtered[$l['linkdate']] = $l;
 379             }
 380         }
 381         ksort($filtered);
 382         return $filtered;
 383     }
 384
 385     /**
 386      * Returns the article corresponding to a smallHash
 387      */
 388     public function filterSmallHash($smallHash)
 389     {
 390         $filtered = array();
 391         foreach ($this->links as $l) {
 392             if ($smallHash == smallHash($l['linkdate'])) {
 393                 // Yes, this is ugly and slow
 394                 $filtered[$l['linkdate']] = $l;
 395                 return $filtered;
 396             }
 397         }
 398         return $filtered;
 399     }
 400
 401     /**
 402      * Returns the list of all tags
 403      * Output: associative array key=tags, value=0
 404      */
 405     public function allTags()
 406     {
 407         $tags = array();
 408         foreach ($this->links as $link) {
 409             foreach (explode(' ', $link['tags']) as $tag) {
 410                 if (!empty($tag)) {
 411                     $tags[$tag] = (empty($tags[$tag]) ? 1 : $tags[$tag] + 1);
 412                 }
 413             }
 414         }
 415         // Sort tags by usage (most used tag first)
 416         arsort($tags);
 417         return $tags;
 418     }
 419
 420     /**
 421      * Returns the list of days containing articles (oldest first)
 422      * Output: An array containing days (in format YYYYMMDD).
 423      */
 424     public function days()
 425     {
 426         $linkDays = array();
 427         foreach (array_keys($this->links) as $day) {
 428             $linkDays[substr($day, 0, 8)] = 0;
 429         }
 430         $linkDays = array_keys($linkDays);
 431         sort($linkDays);
 432         return $linkDays;
 433     }
 434 }
 435 ?>