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