application/Utils.php

   1 <?php
   2 /**
   3  * Shaarli utilities
   4  */
   5
   6 /**
   7  * Logs a message to a text file
   8  *
   9  * The log format is compatible with fail2ban.
  10  *
  11  * @param string $logFile  where to write the logs
  12  * @param string $clientIp the client's remote IPv4/IPv6 address
  13  * @param string $message  the message to log
  14  */
  15 function logm($logFile, $clientIp, $message)
  16 {
  17     file_put_contents(
  18         $logFile,
  19         date('Y/m/d H:i:s').' - '.$clientIp.' - '.strval($message).PHP_EOL,
  20         FILE_APPEND
  21     );
  22 }
  23
  24 /**
  25  *  Returns the small hash of a string, using RFC 4648 base64url format
  26  *
  27  *  Small hashes:
  28  *   - are unique (well, as unique as crc32, at last)
  29  *   - are always 6 characters long.
  30  *   - only use the following characters: a-z A-Z 0-9 - _ @
  31  *   - are NOT cryptographically secure (they CAN be forged)
  32  *
  33  *  In Shaarli, they are used as a tinyurl-like link to individual entries,
  34  *  e.g. smallHash('20111006_131924') --> yZH23w
  35  */
  36 function smallHash($text)
  37 {
  38     $t = rtrim(base64_encode(hash('crc32', $text, true)), '=');
  39     return strtr($t, '+/', '-_');
  40 }
  41
  42 /**
  43  * Tells if a string start with a substring
  44  */
  45 function startsWith($haystack, $needle, $case=true)
  46 {
  47     if ($case) {
  48         return (strcmp(substr($haystack, 0, strlen($needle)), $needle) === 0);
  49     }
  50     return (strcasecmp(substr($haystack, 0, strlen($needle)), $needle) === 0);
  51 }
  52
  53 /**
  54  * Tells if a string ends with a substring
  55  */
  56 function endsWith($haystack, $needle, $case=true)
  57 {
  58     if ($case) {
  59         return (strcmp(substr($haystack, strlen($haystack) - strlen($needle)), $needle) === 0);
  60     }
  61     return (strcasecmp(substr($haystack, strlen($haystack) - strlen($needle)), $needle) === 0);
  62 }
  63
  64 /**
  65  * htmlspecialchars wrapper
  66  */
  67 function escape($str)
  68 {
  69     return htmlspecialchars($str, ENT_COMPAT, 'UTF-8', false);
  70 }
  71
  72 /**
  73  * Link sanitization before templating
  74  */
  75 function sanitizeLink(&$link)
  76 {
  77     $link['url'] = escape($link['url']); // useful?
  78     $link['title'] = escape($link['title']);
  79     $link['description'] = escape($link['description']);
  80     $link['tags'] = escape($link['tags']);
  81 }
  82
  83 /**
  84  * Checks if a string represents a valid date
  85
  86  * @param string $format The expected DateTime format of the string
  87  * @param string $string A string-formatted date
  88  *
  89  * @return bool whether the string is a valid date
  90  *
  91  * @see http://php.net/manual/en/class.datetime.php
  92  * @see http://php.net/manual/en/datetime.createfromformat.php
  93  */
  94 function checkDateFormat($format, $string)
  95 {
  96     $date = DateTime::createFromFormat($format, $string);
  97     return $date && $date->format($string) == $string;
  98 }
  99
 100 /**
 101  * Generate a header location from HTTP_REFERER.
 102  * Make sure the referer is Shaarli itself and prevent redirection loop.
 103  *
 104  * @param string $referer - HTTP_REFERER.
 105  * @param string $host - Server HOST.
 106  * @param array $loopTerms - Contains list of term to prevent redirection loop.
 107  *
 108  * @return string $referer - final referer.
 109  */
 110 function generateLocation($referer, $host, $loopTerms = array())
 111 {
 112     $finalReferer = '?';
 113
 114     // No referer if it contains any value in $loopCriteria.
 115     foreach ($loopTerms as $value) {
 116         if (strpos($referer, $value) !== false) {
 117             return $finalReferer;
 118         }
 119     }
 120
 121     // Remove port from HTTP_HOST
 122     if ($pos = strpos($host, ':')) {
 123         $host = substr($host, 0, $pos);
 124     }
 125
 126     $refererHost = parse_url($referer, PHP_URL_HOST);
 127     if (!empty($referer) && (strpos($refererHost, $host) !== false || startsWith('?', $refererHost))) {
 128         $finalReferer = $referer;
 129     }
 130
 131     return $finalReferer;
 132 }
 133
 134 /**
 135  * Validate session ID to prevent Full Path Disclosure.
 136  *
 137  * See #298.
 138  * The session ID's format depends on the hash algorithm set in PHP settings
 139  *
 140  * @param string $sessionId Session ID
 141  *
 142  * @return true if valid, false otherwise.
 143  *
 144  * @see http://php.net/manual/en/function.hash-algos.php
 145  * @see http://php.net/manual/en/session.configuration.php
 146  */
 147 function is_session_id_valid($sessionId)
 148 {
 149     if (empty($sessionId)) {
 150         return false;
 151     }
 152
 153     if (!$sessionId) {
 154         return false;
 155     }
 156
 157     if (!preg_match('/^[a-zA-Z0-9,-]{2,128}$/', $sessionId)) {
 158         return false;
 159     }
 160
 161     return true;
 162 }
 163
 164 /**
 165  * In a string, converts URLs to clickable links.
 166  *
 167  * @param string $text       input string.
 168  * @param string $redirector if a redirector is set, use it to gerenate links.
 169  *
 170  * @return string returns $text with all links converted to HTML links.
 171  *
 172  * @see Function inspired from http://www.php.net/manual/en/function.preg-replace.php#85722
 173  */
 174 function text2clickable($text, $redirector)
 175 {
 176     $regex = '!(((?:https?|ftp|file)://|apt:|magnet:)\S+[[:alnum:]]/?)!si';
 177
 178     if (empty($redirector)) {
 179         return preg_replace($regex, '<a href="$1">$1</a>', $text);
 180     }
 181     // Redirector is set, urlencode the final URL.
 182     return preg_replace_callback(
 183         $regex,
 184         function ($matches) use ($redirector) {
 185             return '<a href="' . $redirector . urlencode($matches[1]) .'">'. $matches[1] .'</a>';
 186         },
 187         $text
 188     );
 189 }
 190
 191 /**
 192  * This function inserts &nbsp; where relevant so that multiple spaces are properly displayed in HTML
 193  * even in the absence of <pre>  (This is used in description to keep text formatting).
 194  *
 195  * @param string $text input text.
 196  *
 197  * @return string formatted text.
 198  */
 199 function space2nbsp($text)
 200 {
 201     return preg_replace('/(^| ) /m', '$1&nbsp;', $text);
 202 }
 203
 204 /**
 205  * Format Shaarli's description
 206  * TODO: Move me to ApplicationUtils when it's ready.
 207  *
 208  * @param string $description shaare's description.
 209  * @param string $redirector  if a redirector is set, use it to gerenate links.
 210  *
 211  * @return string formatted description.
 212  */
 213 function format_description($description, $redirector) {
 214     return nl2br(space2nbsp(text2clickable($description, $redirector)));
 215 }