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  *  built once with the combination of the date and item ID.
  35  *  e.g. smallHash('20111006_131924' . 142) --> eaWxtQ
  36  *
  37  * @warning before v0.8.1, smallhashes were built only with the date,
  38  *          and their value has been preserved.
  39  *
  40  * @param string $text Create a hash from this text.
  41  *
  42  * @return string generated small hash.
  43  */
  44 function smallHash($text)
  45 {
  46     $t = rtrim(base64_encode(hash('crc32', $text, true)), '=');
  47     return strtr($t, '+/', '-_');
  48 }
  49
  50 /**
  51  * Tells if a string start with a substring
  52  *
  53  * @param string $haystack Given string.
  54  * @param string $needle   String to search at the beginning of $haystack.
  55  * @param bool   $case     Case sensitive.
  56  *
  57  * @return bool True if $haystack starts with $needle.
  58  */
  59 function startsWith($haystack, $needle, $case = true)
  60 {
  61     if ($case) {
  62         return (strcmp(substr($haystack, 0, strlen($needle)), $needle) === 0);
  63     }
  64     return (strcasecmp(substr($haystack, 0, strlen($needle)), $needle) === 0);
  65 }
  66
  67 /**
  68  * Tells if a string ends with a substring
  69  *
  70  * @param string $haystack Given string.
  71  * @param string $needle   String to search at the end of $haystack.
  72  * @param bool   $case     Case sensitive.
  73  *
  74  * @return bool True if $haystack ends with $needle.
  75  */
  76 function endsWith($haystack, $needle, $case = true)
  77 {
  78     if ($case) {
  79         return (strcmp(substr($haystack, strlen($haystack) - strlen($needle)), $needle) === 0);
  80     }
  81     return (strcasecmp(substr($haystack, strlen($haystack) - strlen($needle)), $needle) === 0);
  82 }
  83
  84 /**
  85  * Htmlspecialchars wrapper
  86  * Support multidimensional array of strings.
  87  *
  88  * @param mixed $input Data to escape: a single string or an array of strings.
  89  *
  90  * @return string escaped.
  91  */
  92 function escape($input)
  93 {
  94     if (is_array($input)) {
  95         $out = array();
  96         foreach($input as $key => $value) {
  97             $out[$key] = escape($value);
  98         }
  99         return $out;
 100     }
 101     return htmlspecialchars($input, ENT_COMPAT, 'UTF-8', false);
 102 }
 103
 104 /**
 105  * Reverse the escape function.
 106  *
 107  * @param string $str the string to unescape.
 108  *
 109  * @return string unescaped string.
 110  */
 111 function unescape($str)
 112 {
 113     return htmlspecialchars_decode($str);
 114 }
 115
 116 /**
 117  * Sanitize link before rendering.
 118  *
 119  * @param array $link Link to escape.
 120  */
 121 function sanitizeLink(&$link)
 122 {
 123     $link['url'] = escape($link['url']); // useful?
 124     $link['title'] = escape($link['title']);
 125     $link['description'] = escape($link['description']);
 126     $link['tags'] = escape($link['tags']);
 127 }
 128
 129 /**
 130  * Checks if a string represents a valid date
 131
 132  * @param string $format The expected DateTime format of the string
 133  * @param string $string A string-formatted date
 134  *
 135  * @return bool whether the string is a valid date
 136  *
 137  * @see http://php.net/manual/en/class.datetime.php
 138  * @see http://php.net/manual/en/datetime.createfromformat.php
 139  */
 140 function checkDateFormat($format, $string)
 141 {
 142     $date = DateTime::createFromFormat($format, $string);
 143     return $date && $date->format($string) == $string;
 144 }
 145
 146 /**
 147  * Generate a header location from HTTP_REFERER.
 148  * Make sure the referer is Shaarli itself and prevent redirection loop.
 149  *
 150  * @param string $referer - HTTP_REFERER.
 151  * @param string $host - Server HOST.
 152  * @param array $loopTerms - Contains list of term to prevent redirection loop.
 153  *
 154  * @return string $referer - final referer.
 155  */
 156 function generateLocation($referer, $host, $loopTerms = array())
 157 {
 158     $finalReferer = '?';
 159
 160     // No referer if it contains any value in $loopCriteria.
 161     foreach ($loopTerms as $value) {
 162         if (strpos($referer, $value) !== false) {
 163             return $finalReferer;
 164         }
 165     }
 166
 167     // Remove port from HTTP_HOST
 168     if ($pos = strpos($host, ':')) {
 169         $host = substr($host, 0, $pos);
 170     }
 171
 172     $refererHost = parse_url($referer, PHP_URL_HOST);
 173     if (!empty($referer) && (strpos($refererHost, $host) !== false || startsWith('?', $refererHost))) {
 174         $finalReferer = $referer;
 175     }
 176
 177     return $finalReferer;
 178 }
 179
 180 /**
 181  * Validate session ID to prevent Full Path Disclosure.
 182  *
 183  * See #298.
 184  * The session ID's format depends on the hash algorithm set in PHP settings
 185  *
 186  * @param string $sessionId Session ID
 187  *
 188  * @return true if valid, false otherwise.
 189  *
 190  * @see http://php.net/manual/en/function.hash-algos.php
 191  * @see http://php.net/manual/en/session.configuration.php
 192  */
 193 function is_session_id_valid($sessionId)
 194 {
 195     if (empty($sessionId)) {
 196         return false;
 197     }
 198
 199     if (!$sessionId) {
 200         return false;
 201     }
 202
 203     if (!preg_match('/^[a-zA-Z0-9,-]{2,128}$/', $sessionId)) {
 204         return false;
 205     }
 206
 207     return true;
 208 }
 209
 210 /**
 211  * Sniff browser language to set the locale automatically.
 212  * Note that is may not work on your server if the corresponding locale is not installed.
 213  *
 214  * @param string $headerLocale Locale send in HTTP headers (e.g. "fr,fr-fr;q=0.8,en;q=0.5,en-us;q=0.3").
 215  **/
 216 function autoLocale($headerLocale)
 217 {
 218     // Default if browser does not send HTTP_ACCEPT_LANGUAGE
 219     $attempts = array('en_US', 'en_US.utf8', 'en_US.UTF-8');
 220     if (isset($headerLocale)) {
 221         // (It's a bit crude, but it works very well. Preferred language is always presented first.)
 222         if (preg_match('/([a-z]{2,3})[-_]?([a-z]{2})?/i', $headerLocale, $matches)) {
 223             $first = [strtolower($matches[1]), strtoupper($matches[1])];
 224             $separators = ['_', '-'];
 225             $encodings = ['utf8', 'UTF-8'];
 226             if (!empty($matches[2])) {
 227                 $second = [strtoupper($matches[2]), strtolower($matches[2])];
 228                 $attempts = cartesian_product_generator([$first, $separators, $second, ['.'], $encodings]);
 229             } else {
 230                 $attempts = cartesian_product_generator([$first, $separators, $first, ['.'], $encodings]);
 231             }
 232         }
 233     }
 234     setlocale(LC_ALL, implode('implode', iterator_to_array($attempts)));
 235 }
 236
 237 /**
 238  * Build a Generator object representing the cartesian product from given $items.
 239  *
 240  * Example:
 241  *   [['a'], ['b', 'c']]
 242  * will generate:
 243  *   [
 244  *      ['a', 'b'],
 245  *      ['a', 'c'],
 246  *   ]
 247  *
 248  * @param array $items array of array of string
 249  *
 250  * @return Generator representing the cartesian product of given array.
 251  *
 252  * @see https://en.wikipedia.org/wiki/Cartesian_product
 253  */
 254 function cartesian_product_generator($items)
 255 {
 256     if (empty($items)) {
 257         yield [];
 258     }
 259     $subArray = array_pop($items);
 260     if (empty($subArray)) {
 261         return;
 262     }
 263     foreach (cartesian_product_generator($items) as $item) {
 264         foreach ($subArray as $value) {
 265             yield $item + [count($item) => $value];
 266         }
 267     }
 268 }
 269
 270 /**
 271  * Generates a default API secret.
 272  *
 273  * Note that the random-ish methods used in this function are predictable,
 274  * which makes them NOT suitable for crypto.
 275  * BUT the random string is salted with the salt and hashed with the username.
 276  * It makes the generated API secret secured enough for Shaarli.
 277  *
 278  * PHP 7 provides random_int(), designed for cryptography.
 279  * More info: http://stackoverflow.com/questions/4356289/php-random-string-generator
 280
 281  * @param string $username Shaarli login username
 282  * @param string $salt     Shaarli password hash salt
 283  *
 284  * @return string|bool Generated API secret, 12 char length.
 285  *                     Or false if invalid parameters are provided (which will make the API unusable).
 286  */
 287 function generate_api_secret($username, $salt)
 288 {
 289     if (empty($username) || empty($salt)) {
 290         return false;
 291     }
 292
 293     return str_shuffle(substr(hash_hmac('sha512', uniqid($salt), $username), 10, 12));
 294 }
 295
 296 /**
 297  * Trim string, replace sequences of whitespaces by a single space.
 298  * PHP equivalent to `normalize-space` XSLT function.
 299  *
 300  * @param string $string Input string.
 301  *
 302  * @return mixed Normalized string.
 303  */
 304 function normalize_spaces($string)
 305 {
 306     return preg_replace('/\s{2,}/', ' ', trim($string));
 307 }
 308
 309 /**
 310  * Format the date according to the locale.
 311  *
 312  * Requires php-intl to display international datetimes,
 313  * otherwise default format '%c' will be returned.
 314  *
 315  * @param DateTime $date to format.
 316  * @param bool     $intl Use international format if true.
 317  *
 318  * @return bool|string Formatted date, or false if the input is invalid.
 319  */
 320 function format_date($date, $intl = true)
 321 {
 322     if (! $date instanceof DateTime) {
 323         return false;
 324     }
 325
 326     if (! $intl || ! class_exists('IntlDateFormatter')) {
 327         return strftime('%c', $date->getTimestamp());
 328     }
 329
 330     $formatter = new IntlDateFormatter(
 331         setlocale(LC_TIME, 0),
 332         IntlDateFormatter::LONG,
 333         IntlDateFormatter::LONG
 334     );
 335
 336     return $formatter->format($date);
 337 }