application/Utils.php

   1 <?php
   2 /**
   3  * Shaarli utilities
   4  */
   5
   6 /**
   7  *  Returns the small hash of a string, using RFC 4648 base64url format
   8  *
   9  *  Small hashes:
  10  *   - are unique (well, as unique as crc32, at last)
  11  *   - are always 6 characters long.
  12  *   - only use the following characters: a-z A-Z 0-9 - _ @
  13  *   - are NOT cryptographically secure (they CAN be forged)
  14  *
  15  *  In Shaarli, they are used as a tinyurl-like link to individual entries,
  16  *  e.g. smallHash('20111006_131924') --> yZH23w
  17  */
  18 function smallHash($text)
  19 {
  20     $t = rtrim(base64_encode(hash('crc32', $text, true)), '=');
  21     return strtr($t, '+/', '-_');
  22 }
  23
  24 /**
  25  * Tells if a string start with a substring
  26  */
  27 function startsWith($haystack, $needle, $case=true)
  28 {
  29     if ($case) {
  30         return (strcmp(substr($haystack, 0, strlen($needle)), $needle) === 0);
  31     }
  32     return (strcasecmp(substr($haystack, 0, strlen($needle)), $needle) === 0);
  33 }
  34
  35 /**
  36  * Tells if a string ends with a substring
  37  */
  38 function endsWith($haystack, $needle, $case=true)
  39 {
  40     if ($case) {
  41         return (strcmp(substr($haystack, strlen($haystack) - strlen($needle)), $needle) === 0);
  42     }
  43     return (strcasecmp(substr($haystack, strlen($haystack) - strlen($needle)), $needle) === 0);
  44 }
  45
  46 /**
  47  * htmlspecialchars wrapper
  48  */
  49 function escape($str)
  50 {
  51     return htmlspecialchars($str, ENT_COMPAT, 'UTF-8', false);
  52 }
  53
  54 /**
  55  * Link sanitization before templating
  56  */
  57 function sanitizeLink(&$link)
  58 {
  59     $link['url'] = escape($link['url']); // useful?
  60     $link['title'] = escape($link['title']);
  61     $link['description'] = escape($link['description']);
  62     $link['tags'] = escape($link['tags']);
  63 }
  64
  65 /**
  66  * Checks if a string represents a valid date
  67  *
  68  * @param string        a string-formatted date
  69  * @param format        the expected DateTime format of the string
  70  * @return              whether the string is a valid date
  71  * @see                 http://php.net/manual/en/class.datetime.php
  72  * @see                 http://php.net/manual/en/datetime.createfromformat.php
  73  */
  74 function checkDateFormat($format, $string)
  75 {
  76     $date = DateTime::createFromFormat($format, $string);
  77     return $date && $date->format($string) == $string;
  78 }
  79
  80 /**
  81  * Generate a header location from HTTP_REFERER.
  82  * Make sure the referer is Shaarli itself and prevent redirection loop.
  83  *
  84  * @param string $referer - HTTP_REFERER.
  85  * @param string $host - Server HOST.
  86  * @param array $loopTerms - Contains list of term to prevent redirection loop.
  87  *
  88  * @return string $referer - final referer.
  89  */
  90 function generateLocation($referer, $host, $loopTerms = array())
  91 {
  92     $finalReferer = '?';
  93
  94     // No referer if it contains any value in $loopCriteria.
  95     foreach ($loopTerms as $value) {
  96         if (strpos($referer, $value) !== false) {
  97             return $finalReferer;
  98         }
  99     }
 100
 101     // Remove port from HTTP_HOST
 102     if ($pos = strpos($host, ':')) {
 103         $host = substr($host, 0, $pos);
 104     }
 105
 106     $refererHost = parse_url($referer, PHP_URL_HOST);
 107     if (!empty($referer) && (strpos($refererHost, $host) !== false || startsWith('?', $refererHost))) {
 108         $finalReferer = $referer;
 109     }
 110
 111     return $finalReferer;
 112 }
 113
 114 /**
 115  * Validate session ID to prevent Full Path Disclosure.
 116  *
 117  * See #298.
 118  * The session ID's format depends on the hash algorithm set in PHP settings
 119  *
 120  * @param string $sessionId Session ID
 121  *
 122  * @return true if valid, false otherwise.
 123  *
 124  * @see http://php.net/manual/en/function.hash-algos.php
 125  * @see http://php.net/manual/en/session.configuration.php
 126  */
 127 function is_session_id_valid($sessionId)
 128 {
 129     if (empty($sessionId)) {
 130         return false;
 131     }
 132
 133     if (!$sessionId) {
 134         return false;
 135     }
 136
 137     if (!preg_match('/^[a-zA-Z0-9,-]{2,128}$/', $sessionId)) {
 138         return false;
 139     }
 140
 141     return true;
 142 }
 143
 144 /**
 145  * In a string, converts URLs to clickable links.
 146  *
 147  * @param string $text       input string.
 148  * @param string $redirector if a redirector is set, use it to gerenate links.
 149  *
 150  * @return string returns $text with all links converted to HTML links.
 151  *
 152  * @see Function inspired from http://www.php.net/manual/en/function.preg-replace.php#85722
 153  */
 154 function text2clickable($text, $redirector)
 155 {
 156     $regex = '!(((?:https?|ftp|file)://|apt:|magnet:)\S+[[:alnum:]]/?)!si';
 157
 158     if (empty($redirector)) {
 159         return preg_replace($regex, '<a href="$1">$1</a>', $text);
 160     }
 161     // Redirector is set, urlencode the final URL.
 162     return preg_replace_callback(
 163         $regex,
 164         function ($matches) use ($redirector) {
 165             return '<a href="' . $redirector . urlencode($matches[1]) .'">'. $matches[1] .'</a>';
 166         },
 167         $text
 168     );
 169 }
 170
 171 /**
 172  * This function inserts &nbsp; where relevant so that multiple spaces are properly displayed in HTML
 173  * even in the absence of <pre>  (This is used in description to keep text formatting).
 174  *
 175  * @param string $text input text.
 176  *
 177  * @return string formatted text.
 178  */
 179 function space2nbsp($text)
 180 {
 181     return preg_replace('/(^| ) /m', '$1&nbsp;', $text);
 182 }
 183
 184 /**
 185  * Format Shaarli's description
 186  * TODO: Move me to ApplicationUtils when it's ready.
 187  *
 188  * @param string $description shaare's description.
 189  * @param string $redirector  if a redirector is set, use it to gerenate links.
 190  *
 191  * @return string formatted description.
 192  */
 193 function format_description($description, $redirector) {
 194     return nl2br(space2nbsp(text2clickable($description, $redirector)));
 195 }