application/bookmark/LinkUtils.php

   1 <?php
   2
   3 use Shaarli\Bookmark\Bookmark;
   4
   5 /**
   6  * Extract title from an HTML document.
   7  *
   8  * @param string $html HTML content where to look for a title.
   9  *
  10  * @return bool|string Extracted title if found, false otherwise.
  11  */
  12 function html_extract_title($html)
  13 {
  14     if (preg_match('!<title.*?>(.*?)</title>!is', $html, $matches)) {
  15         return trim(str_replace("\n", '', $matches[1]));
  16     }
  17     return false;
  18 }
  19
  20 /**
  21  * Extract charset from HTTP header if it's defined.
  22  *
  23  * @param string $header HTTP header Content-Type line.
  24  *
  25  * @return bool|string Charset string if found (lowercase), false otherwise.
  26  */
  27 function header_extract_charset($header)
  28 {
  29     preg_match('/charset=["\']?([^; "\']+)/i', $header, $match);
  30     if (! empty($match[1])) {
  31         return strtolower(trim($match[1]));
  32     }
  33
  34     return false;
  35 }
  36
  37 /**
  38  * Extract charset HTML content (tag <meta charset>).
  39  *
  40  * @param string $html HTML content where to look for charset.
  41  *
  42  * @return bool|string Charset string if found, false otherwise.
  43  */
  44 function html_extract_charset($html)
  45 {
  46     // Get encoding specified in HTML header.
  47     preg_match('#<meta .*charset=["\']?([^";\'>/]+)["\']? */?>#Usi', $html, $enc);
  48     if (!empty($enc[1])) {
  49         return strtolower($enc[1]);
  50     }
  51
  52     return false;
  53 }
  54
  55 /**
  56  * Extract meta tag from HTML content in either:
  57  *   - OpenGraph: <meta property="og:[tag]" ...>
  58  *   - Meta tag: <meta name="[tag]" ...>
  59  *
  60  * @param string $tag  Name of the tag to retrieve.
  61  * @param string $html HTML content where to look for charset.
  62  *
  63  * @return bool|string Charset string if found, false otherwise.
  64  */
  65 function html_extract_tag($tag, $html)
  66 {
  67     $propertiesKey = ['property', 'name', 'itemprop'];
  68     $properties = implode('|', $propertiesKey);
  69     // We need a OR here to accept either 'property=og:noquote' or 'property="og:unrelated og:my-tag"'
  70     $orCondition  = '["\']?(?:og:)?'. $tag .'["\']?|["\'][^\'"]*?(?:og:)?' . $tag . '[^\'"]*?[\'"]';
  71     // Try to retrieve OpenGraph image.
  72     $ogRegex = '#<meta[^>]+(?:'. $properties .')=(?:'. $orCondition .')[^>]*content=["\'](.*?)["\'].*?>#';
  73     // If the attributes are not in the order property => content (e.g. Github)
  74     // New regex to keep this readable... more or less.
  75     $ogRegexReverse = '#<meta[^>]+content=["\'](.*?)["\'][^>]+(?:'. $properties .')=(?:'. $orCondition .').*?>#';
  76
  77     if (preg_match($ogRegex, $html, $matches) > 0
  78         || preg_match($ogRegexReverse, $html, $matches) > 0
  79     ) {
  80         return $matches[1];
  81     }
  82
  83     return false;
  84 }
  85
  86 /**
  87  * In a string, converts URLs to clickable bookmarks.
  88  *
  89  * @param string $text       input string.
  90  *
  91  * @return string returns $text with all bookmarks converted to HTML bookmarks.
  92  *
  93  * @see Function inspired from http://www.php.net/manual/en/function.preg-replace.php#85722
  94  */
  95 function text2clickable($text)
  96 {
  97     $regex = '!(((?:https?|ftp|file)://|apt:|magnet:)\S+[a-z0-9\(\)]/?)!si';
  98     return preg_replace($regex, '<a href="$1">$1</a>', $text);
  99 }
 100
 101 /**
 102  * Auto-link hashtags.
 103  *
 104  * @param string $description Given description.
 105  * @param string $indexUrl    Root URL.
 106  *
 107  * @return string Description with auto-linked hashtags.
 108  */
 109 function hashtag_autolink($description, $indexUrl = '')
 110 {
 111     /*
 112      * To support unicode: http://stackoverflow.com/a/35498078/1484919
 113      * \p{Pc} - to match underscore
 114      * \p{N} - numeric character in any script
 115      * \p{L} - letter from any language
 116      * \p{Mn} - any non marking space (accents, umlauts, etc)
 117      */
 118     $regex = '/(^|\s)#([\p{Pc}\p{N}\p{L}\p{Mn}]+)/mui';
 119     $replacement = '$1<a href="'. $indexUrl .'./add-tag/$2" title="Hashtag $2">#$2</a>';
 120     return preg_replace($regex, $replacement, $description);
 121 }
 122
 123 /**
 124  * This function inserts &nbsp; where relevant so that multiple spaces are properly displayed in HTML
 125  * even in the absence of <pre>  (This is used in description to keep text formatting).
 126  *
 127  * @param string $text input text.
 128  *
 129  * @return string formatted text.
 130  */
 131 function space2nbsp($text)
 132 {
 133     return preg_replace('/(^| ) /m', '$1&nbsp;', $text);
 134 }
 135
 136 /**
 137  * Format Shaarli's description
 138  *
 139  * @param string $description shaare's description.
 140  * @param string $indexUrl    URL to Shaarli's index.
 141
 142  * @return string formatted description.
 143  */
 144 function format_description($description, $indexUrl = '')
 145 {
 146     return nl2br(space2nbsp(hashtag_autolink(text2clickable($description), $indexUrl)));
 147 }
 148
 149 /**
 150  * Generate a small hash for a link.
 151  *
 152  * @param DateTime $date Link creation date.
 153  * @param int      $id   Link ID.
 154  *
 155  * @return string the small hash generated from link data.
 156  */
 157 function link_small_hash($date, $id)
 158 {
 159     return smallHash($date->format(Bookmark::LINK_DATE_FORMAT) . $id);
 160 }
 161
 162 /**
 163  * Returns whether or not the link is an internal note.
 164  * Its URL starts by `?` because it's actually a permalink.
 165  *
 166  * @param string $linkUrl
 167  *
 168  * @return bool true if internal note, false otherwise.
 169  */
 170 function is_note($linkUrl)
 171 {
 172     return isset($linkUrl[0]) && $linkUrl[0] === '?';
 173 }