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)), $needle) === 0);
  44 }
  45
  46 /**
  47  * Same as nl2br(), but escapes < and >
  48  */
  49 function nl2br_escaped($html)
  50 {
  51     return str_replace('>','&gt;',str_replace('<','&lt;',nl2br($html)));
  52 }
  53
  54 /**
  55  * htmlspecialchars wrapper
  56  */
  57 function escape($str)
  58 {
  59     return htmlspecialchars($str, ENT_COMPAT, 'UTF-8', false);
  60 }
  61
  62 /**
  63  * Link sanitization before templating
  64  */
  65 function sanitizeLink(&$link)
  66 {
  67     $link['url'] = escape($link['url']); // useful?
  68     $link['title'] = escape($link['title']);
  69     $link['description'] = escape($link['description']);
  70     $link['tags'] = escape($link['tags']);
  71 }
  72
  73 /**
  74  * Checks if a string represents a valid date
  75  *
  76  * @param string        a string-formatted date
  77  * @param format        the expected DateTime format of the string
  78  * @return              whether the string is a valid date
  79  * @see                 http://php.net/manual/en/class.datetime.php
  80  * @see                 http://php.net/manual/en/datetime.createfromformat.php
  81  */
  82 function checkDateFormat($format, $string)
  83 {
  84     $date = DateTime::createFromFormat($format, $string);
  85     return $date && $date->format($string) == $string;
  86 }
  87 ?>