MyShaarli/application/bookmark/LinkUtils.php
ArthurHoaro 458b6b9918
Merge pull request #1540 from ArthurHoaro/fix/metadata-regexes
Improve regex to extract HTML metadata (title, description, etc.)
2020-10-13 12:26:55 +02:00

173 lines
4.9 KiB
PHP

<?php
use Shaarli\Bookmark\Bookmark;
/**
* Extract title from an HTML document.
*
* @param string $html HTML content where to look for a title.
*
* @return bool|string Extracted title if found, false otherwise.
*/
function html_extract_title($html)
{
if (preg_match('!<title.*?>(.*?)</title>!is', $html, $matches)) {
return trim(str_replace("\n", '', $matches[1]));
}
return false;
}
/**
* Extract charset from HTTP header if it's defined.
*
* @param string $header HTTP header Content-Type line.
*
* @return bool|string Charset string if found (lowercase), false otherwise.
*/
function header_extract_charset($header)
{
preg_match('/charset=["\']?([^; "\']+)/i', $header, $match);
if (! empty($match[1])) {
return strtolower(trim($match[1]));
}
return false;
}
/**
* Extract charset HTML content (tag <meta charset>).
*
* @param string $html HTML content where to look for charset.
*
* @return bool|string Charset string if found, false otherwise.
*/
function html_extract_charset($html)
{
// Get encoding specified in HTML header.
preg_match('#<meta .*charset=["\']?([^";\'>/]+)["\']? */?>#Usi', $html, $enc);
if (!empty($enc[1])) {
return strtolower($enc[1]);
}
return false;
}
/**
* Extract meta tag from HTML content in either:
* - OpenGraph: <meta property="og:[tag]" ...>
* - Meta tag: <meta name="[tag]" ...>
*
* @param string $tag Name of the tag to retrieve.
* @param string $html HTML content where to look for charset.
*
* @return bool|string Charset string if found, false otherwise.
*/
function html_extract_tag($tag, $html)
{
$propertiesKey = ['property', 'name', 'itemprop'];
$properties = implode('|', $propertiesKey);
// We need a OR here to accept either 'property=og:noquote' or 'property="og:unrelated og:my-tag"'
$orCondition = '["\']?(?:og:)?'. $tag .'["\']?|["\'][^\'"]*?(?:og:)?' . $tag . '[^\'"]*?[\'"]';
// Try to retrieve OpenGraph image.
$ogRegex = '#<meta[^>]+(?:'. $properties .')=(?:'. $orCondition .')[^>]*content=["\'](.*?)["\'].*?>#';
// If the attributes are not in the order property => content (e.g. Github)
// New regex to keep this readable... more or less.
$ogRegexReverse = '#<meta[^>]+content=["\'](.*?)["\'][^>]+(?:'. $properties .')=(?:'. $orCondition .').*?>#';
if (preg_match($ogRegex, $html, $matches) > 0
|| preg_match($ogRegexReverse, $html, $matches) > 0
) {
return $matches[1];
}
return false;
}
/**
* In a string, converts URLs to clickable bookmarks.
*
* @param string $text input string.
*
* @return string returns $text with all bookmarks converted to HTML bookmarks.
*
* @see Function inspired from http://www.php.net/manual/en/function.preg-replace.php#85722
*/
function text2clickable($text)
{
$regex = '!(((?:https?|ftp|file)://|apt:|magnet:)\S+[a-z0-9\(\)]/?)!si';
return preg_replace($regex, '<a href="$1">$1</a>', $text);
}
/**
* Auto-link hashtags.
*
* @param string $description Given description.
* @param string $indexUrl Root URL.
*
* @return string Description with auto-linked hashtags.
*/
function hashtag_autolink($description, $indexUrl = '')
{
/*
* To support unicode: http://stackoverflow.com/a/35498078/1484919
* \p{Pc} - to match underscore
* \p{N} - numeric character in any script
* \p{L} - letter from any language
* \p{Mn} - any non marking space (accents, umlauts, etc)
*/
$regex = '/(^|\s)#([\p{Pc}\p{N}\p{L}\p{Mn}]+)/mui';
$replacement = '$1<a href="'. $indexUrl .'./add-tag/$2" title="Hashtag $2">#$2</a>';
return preg_replace($regex, $replacement, $description);
}
/**
* This function inserts &nbsp; where relevant so that multiple spaces are properly displayed in HTML
* even in the absence of <pre> (This is used in description to keep text formatting).
*
* @param string $text input text.
*
* @return string formatted text.
*/
function space2nbsp($text)
{
return preg_replace('/(^| ) /m', '$1&nbsp;', $text);
}
/**
* Format Shaarli's description
*
* @param string $description shaare's description.
* @param string $indexUrl URL to Shaarli's index.
* @return string formatted description.
*/
function format_description($description, $indexUrl = '')
{
return nl2br(space2nbsp(hashtag_autolink(text2clickable($description), $indexUrl)));
}
/**
* Generate a small hash for a link.
*
* @param DateTime $date Link creation date.
* @param int $id Link ID.
*
* @return string the small hash generated from link data.
*/
function link_small_hash($date, $id)
{
return smallHash($date->format(Bookmark::LINK_DATE_FORMAT) . $id);
}
/**
* Returns whether or not the link is an internal note.
* Its URL starts by `?` because it's actually a permalink.
*
* @param string $linkUrl
*
* @return bool true if internal note, false otherwise.
*/
function is_note($linkUrl)
{
return isset($linkUrl[0]) && $linkUrl[0] === '?';
}