+<?php
+/**
+ * Data storage for links.
+ *
+ * This object behaves like an associative array.
+ *
+ * Example:
+ * $myLinks = new LinkDB();
+ * echo $myLinks['20110826_161819']['title'];
+ * foreach ($myLinks as $link)
+ * echo $link['title'].' at url '.$link['url'].'; description:'.$link['description'];
+ *
+ * Available keys:
+ * - description: description of the entry
+ * - linkdate: date of the creation of this entry, in the form YYYYMMDD_HHMMSS
+ * (e.g.'20110914_192317')
+ * - private: Is this link private? 0=no, other value=yes
+ * - tags: tags attached to this entry (separated by spaces)
+ * - title Title of the link
+ * - url URL of the link. Can be absolute or relative.
+ * Relative URLs are permalinks (e.g.'?m-ukcw')
+ *
+ * Implements 3 interfaces:
+ * - ArrayAccess: behaves like an associative array;
+ * - Countable: there is a count() method;
+ * - Iterator: usable in foreach () loops.
+ */
+class LinkDB implements Iterator, Countable, ArrayAccess
+{
+ // List of links (associative array)
+ // - key: link date (e.g. "20110823_124546"),
+ // - value: associative array (keys: title, description...)
+ private $links;
+
+ // List of all recorded URLs (key=url, value=linkdate)
+ // for fast reserve search (url-->linkdate)
+ private $urls;
+
+ // List of linkdate keys (for the Iterator interface implementation)
+ private $keys;
+
+ // Position in the $this->keys array (for the Iterator interface)
+ private $position;
+
+ // Is the user logged in? (used to filter private links)
+ private $loggedIn;
+
+ /**
+ * Creates a new LinkDB
+ *
+ * Checks if the datastore exists; else, attempts to create a dummy one.
+ *
+ * @param $isLoggedIn is the user logged in?
+ */
+ function __construct($isLoggedIn)
+ {
+ // FIXME: do not access $GLOBALS, pass the datastore instead
+ $this->loggedIn = $isLoggedIn;
+ $this->checkDB();
+ $this->readdb();
+ }
+
+ /**
+ * Countable - Counts elements of an object
+ */
+ public function count()
+ {
+ return count($this->links);
+ }
+
+ /**
+ * ArrayAccess - Assigns a value to the specified offset
+ */
+ public function offsetSet($offset, $value)
+ {
+ // TODO: use exceptions instead of "die"
+ if (!$this->loggedIn) {
+ die('You are not authorized to add a link.');
+ }
+ if (empty($value['linkdate']) || empty($value['url'])) {
+ die('Internal Error: A link should always have a linkdate and URL.');
+ }
+ if (empty($offset)) {
+ die('You must specify a key.');
+ }
+ $this->links[$offset] = $value;
+ $this->urls[$value['url']]=$offset;
+ }
+
+ /**
+ * ArrayAccess - Whether or not an offset exists
+ */
+ public function offsetExists($offset)
+ {
+ return array_key_exists($offset, $this->links);
+ }
+
+ /**
+ * ArrayAccess - Unsets an offset
+ */
+ public function offsetUnset($offset)
+ {
+ if (!$this->loggedIn) {
+ // TODO: raise an exception
+ die('You are not authorized to delete a link.');
+ }
+ $url = $this->links[$offset]['url'];
+ unset($this->urls[$url]);
+ unset($this->links[$offset]);
+ }
+
+ /**
+ * ArrayAccess - Returns the value at specified offset
+ */
+ public function offsetGet($offset)
+ {
+ return isset($this->links[$offset]) ? $this->links[$offset] : null;
+ }
+
+ /**
+ * Iterator - Returns the current element
+ */
+ function current()
+ {
+ return $this->links[$this->keys[$this->position]];
+ }
+
+ /**
+ * Iterator - Returns the key of the current element
+ */
+ function key()
+ {
+ return $this->keys[$this->position];
+ }
+
+ /**
+ * Iterator - Moves forward to next element
+ */
+ function next()
+ {
+ ++$this->position;
+ }
+
+ /**
+ * Iterator - Rewinds the Iterator to the first element
+ *
+ * Entries are sorted by date (latest first)
+ */
+ function rewind()
+ {
+ $this->keys = array_keys($this->links);
+ rsort($this->keys);
+ $this->position = 0;
+ }
+
+ /**
+ * Iterator - Checks if current position is valid
+ */
+ function valid()
+ {
+ return isset($this->keys[$this->position]);
+ }
+
+ /**
+ * Checks if the DB directory and file exist
+ *
+ * If no DB file is found, creates a dummy DB.
+ */
+ private function checkDB()
+ {
+ if (file_exists($GLOBALS['config']['DATASTORE'])) {
+ return;
+ }
+
+ // Create a dummy database for example
+ $this->links = array();
+ $link = array(
+ 'title'=>'Shaarli - sebsauvage.net',
+ 'url'=>'http://sebsauvage.net/wiki/doku.php?id=php:shaarli',
+ 'description'=>'Welcome to Shaarli! This is a bookmark. To edit or delete me, you must first login.',
+ 'private'=>0,
+ 'linkdate'=>'20110914_190000',
+ 'tags'=>'opensource software'
+ );
+ $this->links[$link['linkdate']] = $link;
+
+ $link = array(
+ 'title'=>'My secret stuff... - Pastebin.com',
+ 'url'=>'http://sebsauvage.net/paste/?8434b27936c09649#bR7XsXhoTiLcqCpQbmOpBi3rq2zzQUC5hBI7ZT1O3x8=',
+ 'description'=>'SShhhh!! I\'m a private link only YOU can see. You can delete me too.',
+ 'private'=>1,
+ 'linkdate'=>'20110914_074522',
+ 'tags'=>'secretstuff'
+ );
+ $this->links[$link['linkdate']] = $link;
+
+ // Write database to disk
+ // TODO: raise an exception if the file is not write-able
+ file_put_contents(
+ // FIXME: do not use $GLOBALS
+ $GLOBALS['config']['DATASTORE'],
+ PHPPREFIX.base64_encode(gzdeflate(serialize($this->links))).PHPSUFFIX
+ );
+ }
+
+ /**
+ * Reads database from disk to memory
+ */
+ private function readdb()
+ {
+ // Read data
+ // Note that gzinflate is faster than gzuncompress.
+ // See: http://www.php.net/manual/en/function.gzdeflate.php#96439
+ // FIXME: do not use $GLOBALS
+ $this->links = array();
+
+ if (file_exists($GLOBALS['config']['DATASTORE'])) {
+ $this->links = unserialize(gzinflate(base64_decode(
+ substr(file_get_contents($GLOBALS['config']['DATASTORE']),
+ strlen(PHPPREFIX), -strlen(PHPSUFFIX)))));
+ }
+
+ // If user is not logged in, filter private links.
+ if (!$this->loggedIn) {
+ $toremove = array();
+ foreach ($this->links as $link) {
+ if ($link['private'] != 0) {
+ $toremove[] = $link['linkdate'];
+ }
+ }
+ foreach ($toremove as $linkdate) {
+ unset($this->links[$linkdate]);
+ }
+ }
+
+ // Keep the list of the mapping URLs-->linkdate up-to-date.
+ $this->urls = array();
+ foreach ($this->links as $link) {
+ $this->urls[$link['url']] = $link['linkdate'];
+ }
+ }
+
+ /**
+ * Saves the database from memory to disk
+ */
+ public function savedb()
+ {
+ if (!$this->loggedIn) {
+ // TODO: raise an Exception instead
+ die('You are not authorized to change the database.');
+ }
+ file_put_contents(
+ $GLOBALS['config']['DATASTORE'],
+ PHPPREFIX.base64_encode(gzdeflate(serialize($this->links))).PHPSUFFIX
+ );
+ invalidateCaches();
+ }
+
+ /**
+ * Returns the link for a given URL, or False if it does not exist.
+ */
+ public function getLinkFromUrl($url)
+ {
+ if (isset($this->urls[$url])) {
+ return $this->links[$this->urls[$url]];
+ }
+ return false;
+ }
+
+ /**
+ * Returns the list of links corresponding to a full-text search
+ *
+ * Searches:
+ * - in the URLs, title and description;
+ * - are case-insensitive.
+ *
+ * Example:
+ * print_r($mydb->filterFulltext('hollandais'));
+ *
+ * mb_convert_case($val, MB_CASE_LOWER, 'UTF-8')
+ * - allows to perform searches on Unicode text
+ * - see https://github.com/shaarli/Shaarli/issues/75 for examples
+ */
+ public function filterFulltext($searchterms)
+ {
+ // FIXME: explode(' ',$searchterms) and perform a AND search.
+ // FIXME: accept double-quotes to search for a string "as is"?
+ $filtered = array();
+ $search = mb_convert_case($searchterms, MB_CASE_LOWER, 'UTF-8');
+ $keys = ['title', 'description', 'url', 'tags'];
+
+ foreach ($this->links as $link) {
+ $found = false;
+
+ foreach ($keys as $key) {
+ if (strpos(mb_convert_case($link[$key], MB_CASE_LOWER, 'UTF-8'),
+ $search) !== false) {
+ $found = true;
+ }
+ }
+
+ if ($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'));
+ */
+ public function filterTags($tags, $casesensitive=false)
+ {
+ // Same as above, we use UTF-8 conversion to handle various graphemes (i.e. cyrillic, or greek)
+ // FIXME: is $casesensitive ever true?
+ $t = str_replace(
+ ',', ' ',
+ ($casesensitive ? $tags : mb_convert_case($tags, MB_CASE_LOWER, 'UTF-8'))
+ );
+
+ $searchtags = explode(' ', $t);
+ $filtered = array();
+
+ foreach ($this->links as $l) {
+ $linktags = explode(
+ ' ',
+ ($casesensitive ? $l['tags']:mb_convert_case($l['tags'], MB_CASE_LOWER, 'UTF-8'))
+ );
+
+ if (count(array_intersect($linktags, $searchtags)) == count($searchtags)) {
+ $filtered[$l['linkdate']] = $l;
+ }
+ }
+ krsort($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'));
+ */
+ public function filterDay($day)
+ {
+ // TODO: check input format
+ $filtered = array();
+ foreach ($this->links as $l) {
+ if (startsWith($l['linkdate'], $day)) {
+ $filtered[$l['linkdate']] = $l;
+ }
+ }
+ ksort($filtered);
+ return $filtered;
+ }
+
+ /**
+ * Returns the article corresponding to a smallHash
+ */
+ public function filterSmallHash($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;
+ }
+ }
+ return $filtered;
+ }
+
+ /**
+ * Returns the list of all tags
+ * Output: associative array key=tags, value=0
+ */
+ public function allTags()
+ {
+ $tags = array();
+ foreach ($this->links as $link) {
+ foreach (explode(' ', $link['tags']) as $tag) {
+ if (!empty($tag)) {
+ $tags[$tag] = (empty($tags[$tag]) ? 1 : $tags[$tag] + 1);
+ }
+ }
+ }
+ // Sort tags by usage (most used tag first)
+ arsort($tags);
+ return $tags;
+ }
+
+ /**
+ * Returns the list of days containing articles (oldest first)
+ * Output: An array containing days (in format YYYYMMDD).
+ */
+ public function days()
+ {
+ $linkDays = array();
+ foreach (array_keys($this->links) as $day) {
+ $linkDays[substr($day, 0, 8)] = 0;
+ }
+ $linkDays = array_keys($linkDays);
+ sort($linkDays);
+ return $linkDays;
+ }
+}
+?>