<?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
{
// Links are stored as a PHP serialized string
private $datastore;
// Datastore PHP prefix
protected static $phpPrefix = '<?php /* ';
// Datastore PHP suffix
protected static $phpSuffix = ' */ ?>';
// 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;
// Hide public links
private $hidePublicLinks;
/**
* Creates a new LinkDB
*
* Checks if the datastore exists; else, attempts to create a dummy one.
*
* @param $isLoggedIn is the user logged in?
*/
function __construct($datastore, $isLoggedIn, $hidePublicLinks)
{
$this->datastore = $datastore;
$this->loggedIn = $isLoggedIn;
$this->hidePublicLinks = $hidePublicLinks;
$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[$this->position]);
}
/**
* Checks if the DB directory and file exist
*
* If no DB file is found, creates a dummy DB.
*/
private function checkDB()
{
if (file_exists($this->datastore)) {
return;
}
// Create a dummy database for example
$this->links = array();
$link = array(
'title'=>' Shaarli: the personal, minimalist, super-fast, no-database delicious clone',
'url'=>'https://github.com/shaarli/Shaarli/wiki',
'description'=>'Welcome to Shaarli! This is your first public bookmark. To edit or delete me, you must first login.
To learn how to use Shaarli, consult the link "Help/documentation" at the bottom of this page.
You use the community supported version of the original Shaarli project, by Sebastien Sauvage.',
'private'=>0,
'linkdate'=> date('Ymd_His'),
'tags'=>'opensource software'
);
$this->links[$link['linkdate']] = $link;
$link = array(
'title'=>'My secret stuff... - Pastebin.com',
'url'=>'http://sebsauvage.net/paste/?8434b27936c09649#bR7XsXhoTiLcqCpQbmOpBi3rq2zzQUC5hBI7ZT1O3x8=',
'description'=>'Shhhh! I\'m a private link only YOU can see. You can delete me too.',
'private'=>1,
'linkdate'=> date('Ymd_His', strtotime('-1 minute')),
'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(
$this->datastore,
self::$phpPrefix.base64_encode(gzdeflate(serialize($this->links))).self::$phpSuffix
);
}
/**
* Reads database from disk to memory
*/
private function readdb()
{
// Public links are hidden and user not logged in => nothing to show
if ($this->hidePublicLinks && !$this->loggedIn) {
$this->links = array();
return;
}
// Read data
// Note that gzinflate is faster than gzuncompress.
// See: http://www.php.net/manual/en/function.gzdeflate.php#96439
$this->links = array();
if (file_exists($this->datastore)) {
$this->links = unserialize(gzinflate(base64_decode(
substr(file_get_contents($this->datastore),
strlen(self::$phpPrefix), -strlen(self::$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']] = $link['linkdate'];
}
// Escape links data
foreach($this->links as &$link) {
sanitizeLink($link);
}
}
/**
* 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(
$this->datastore,
self::$phpPrefix.base64_encode(gzdeflate(serialize($this->links))).self::$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');
$keys = array('title', 'description', 'url', 'tags');
foreach ($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)
{
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 $filtered;
}
/**
* Returns the article corresponding to a smallHash
*/
public function filterSmallHash($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;
}
}
?>
