MyShaarli/application/bookmark/LinkUtils.php
ArthurHoaro 6a4872520c Automatically retrieve description for new bookmarks
If the option is enabled, it will try to find a meta tag containing
the page description and keywords, just like we do for the page title.
It will either look for regular meta tag or OpenGraph ones.

The option is disabled by default.

Note that keywords meta tags is mostly not used.

In `configure` template, the variable associated with this setting
is `$retrieve_description`.

Fixes #1302
2019-07-06 12:21:52 +02:00

297 lines
9.1 KiB
PHP

<?php
use Shaarli\Bookmark\LinkDB;
/**
* Get cURL callback function for CURLOPT_WRITEFUNCTION
*
* @param string $charset to extract from the downloaded page (reference)
* @param string $title to extract from the downloaded page (reference)
* @param string $description to extract from the downloaded page (reference)
* @param string $keywords to extract from the downloaded page (reference)
* @param bool $retrieveDescription Automatically tries to retrieve description and keywords from HTML content
* @param string $curlGetInfo Optionally overrides curl_getinfo function
*
* @return Closure
*/
function get_curl_download_callback(
&$charset,
&$title,
&$description,
&$keywords,
$retrieveDescription,
$curlGetInfo = 'curl_getinfo'
) {
$isRedirected = false;
$currentChunk = 0;
$foundChunk = null;
/**
* cURL callback function for CURLOPT_WRITEFUNCTION (called during the download).
*
* While downloading the remote page, we check that the HTTP code is 200 and content type is 'html/text'
* Then we extract the title and the charset and stop the download when it's done.
*
* @param resource $ch cURL resource
* @param string $data chunk of data being downloaded
*
* @return int|bool length of $data or false if we need to stop the download
*/
return function (&$ch, $data) use (
$retrieveDescription,
$curlGetInfo,
&$charset,
&$title,
&$description,
&$keywords,
&$isRedirected,
&$currentChunk,
&$foundChunk
) {
$currentChunk++;
$responseCode = $curlGetInfo($ch, CURLINFO_RESPONSE_CODE);
if (!empty($responseCode) && in_array($responseCode, [301, 302])) {
$isRedirected = true;
return strlen($data);
}
if (!empty($responseCode) && $responseCode !== 200) {
return false;
}
// After a redirection, the content type will keep the previous request value
// until it finds the next content-type header.
if (! $isRedirected || strpos(strtolower($data), 'content-type') !== false) {
$contentType = $curlGetInfo($ch, CURLINFO_CONTENT_TYPE);
}
if (!empty($contentType) && strpos($contentType, 'text/html') === false) {
return false;
}
if (!empty($contentType) && empty($charset)) {
$charset = header_extract_charset($contentType);
}
if (empty($charset)) {
$charset = html_extract_charset($data);
}
if (empty($title)) {
$title = html_extract_title($data);
$foundChunk = ! empty($title) ? $currentChunk : $foundChunk;
}
if ($retrieveDescription && empty($description)) {
$description = html_extract_tag('description', $data);
$foundChunk = ! empty($description) ? $currentChunk : $foundChunk;
}
if ($retrieveDescription && empty($keywords)) {
$keywords = html_extract_tag('keywords', $data);
if (! empty($keywords)) {
$foundChunk = $currentChunk;
// Keywords use the format tag1, tag2 multiple words, tag
// So we format them to match Shaarli's separator and glue multiple words with '-'
$keywords = implode(' ', array_map(function($keyword) {
return implode('-', preg_split('/\s+/', trim($keyword)));
}, explode(',', $keywords)));
}
}
// We got everything we want, stop the download.
// If we already found either the title, description or keywords,
// it's highly unlikely that we'll found the other metas further than
// in the same chunk of data or the next one. So we also stop the download after that.
if ((!empty($responseCode) && !empty($contentType) && !empty($charset)) && $foundChunk !== null
&& (! $retrieveDescription
|| $foundChunk < $currentChunk
|| (!empty($title) && !empty($description) && !empty($keywords))
)
) {
return false;
}
return strlen($data);
};
}
/**
* 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);
// Try to retrieve OpenGraph image.
$ogRegex = '#<meta[^>]+(?:'. $properties .')=["\']?(?:og:)?'. $tag .'["\'\s][^>]*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 .')=["\']?(?:og)?:'. $tag .'["\'\s/>]#';
if (preg_match($ogRegex, $html, $matches) > 0
|| preg_match($ogRegexReverse, $html, $matches) > 0
) {
return $matches[1];
}
return false;
}
/**
* Count private links in given linklist.
*
* @param array|Countable $links Linklist.
*
* @return int Number of private links.
*/
function count_private($links)
{
$cpt = 0;
foreach ($links as $link) {
if ($link['private']) {
$cpt += 1;
}
}
return $cpt;
}
/**
* In a string, converts URLs to clickable links.
*
* @param string $text input string.
*
* @return string returns $text with all links converted to HTML links.
*
* @see Function inspired from http://www.php.net/manual/en/function.preg-replace.php#85722
*/
function text2clickable($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 .'?addtag=$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(LinkDB::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] === '?';
}