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shaarli#111 thumbnails: gently trade some site specific php code for …
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…site specific regexps/configuration. A bit DRYer and cleaner.

TODO: test flickr image links!

see also shaarli#128
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@mro @ArthurHoaro
mro authored and ArthurHoaro committed Jun 25, 2015
1 parent e0f2c85 commit cf46791
Showing 1 changed file with 57 additions and 43 deletions.
100 changes: 57 additions & 43 deletions index.php
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Original file line number Diff line number Diff line change
Expand Up @@ -1791,6 +1791,11 @@ function buildLinkList($PAGE,$LINKSDB)
// Returns an associative array with thumbnail attributes (src,href,width,height,style,alt)
// Some of them may be missing.
// Return an empty array if no thumbnail available.
//
// So this function makes the choice if there's
// - a ready-to use thumbnail on the internets (bandwidth stealing)
// - an image somewhere that should be downloaded, scaled, cached serverside and used via /?do=genthumbnail
// - no thumbnail available.
function computeThumbnail($url,$href=false)
{
if (!$GLOBALS['config']['ENABLE_THUMBNAILS']) return array();
Expand All @@ -1799,26 +1804,38 @@ function computeThumbnail($url,$href=false)
// For most hosts, the URL of the thumbnail can be easily deduced from the URL of the link.
// (e.g. http://www.youtube.com/watch?v=spVypYk4kto ---> http://img.youtube.com/vi/spVypYk4kto/default.jpg )
// ^^^^^^^^^^^ ^^^^^^^^^^^
$domain = parse_url($url,PHP_URL_HOST);
if ($domain=='youtube.com' || $domain=='www.youtube.com')
{
parse_str(parse_url($url,PHP_URL_QUERY), $params); // Extract video ID and get thumbnail
if (!empty($params['v'])) return array('src'=>'https://img.youtube.com/vi/'.$params['v'].'/default.jpg',
'href'=>$href,'width'=>'120','height'=>'90','alt'=>'YouTube thumbnail');
}
if ($domain=='youtu.be') // Youtube short links
{
$path = parse_url($url,PHP_URL_PATH);
return array('src'=>'https://img.youtube.com/vi'.$path.'/default.jpg',
'href'=>$href,'width'=>'120','height'=>'90','alt'=>'YouTube thumbnail');
}
if ($domain=='pix.toile-libre.org') // pix.toile-libre.org image hosting
// this could easily go into a config file a la data/options.php, e.g. data/thumbnails.php:
$url_patterns_steal_bandwidth = array(
'!^https?://(?:www\.)?YouTube\.com(?::\d+)?/.*?(?:[\?&]v=([^\?&#]+).*$!i'=>array(
// this array becomes the attributes of <img .../>
'alt'=>'YouTube thumbnail', // optional, default: '\\0 thumbnail',
'src'=>'https://img.youtube.com/vi/\\1/default.jpg',
// optional: 'style', default: 'max-width:120px; max-height:150px'
),
'!^https?://(?:www\.)?YouTu\.be(?::\d+)?/([^\?&#/]+).*$!i'=>array(
'alt'=>'YouTube thumbnail',
'src'=>'https://img.youtube.com/vi/\\1/default.jpg',
),
'!^https?://(?:www\.)?(pix\.toile-libre\.org)(?::\d+)?/.*?[?&]img=([^\?&#/]+).*$!i'=>array(
'alt'=>'\\1 thumbnail', // example: re-use the original domain name.
'src'=>'http://pix.toile-libre.org/upload/thumb/\\2',
),
);

foreach($url_patterns_steal_bandwidth as $pattern=>$img_tpl)
{
parse_str(parse_url($url,PHP_URL_QUERY), $params); // Extract image filename.
if (!empty($params) && !empty($params['img'])) return array('src'=>'http://pix.toile-libre.org/upload/thumb/'.urlencode($params['img']),
'href'=>$href,'style'=>'max-width:120px; max-height:150px','alt'=>'pix.toile-libre.org thumbnail');
$src = preg_replace($pattern, $img_tpl['src'], $url, 1, $count);
if (0 < $count) {
$img = $img_tpl;
$img['href'] = $href;
$img['src'] = $src;
$img['alt'] = preg_replace($pattern, empty($img['alt']) ? '\\0 thumbnail' : $img['alt'], $url, 1);
if(empty($img['style'])) $img['style'] = 'max-width:120px; max-height:150px';
return $img;
}
}

$domain = parse_url($url,PHP_URL_HOST);
if ($domain=='imgur.com')
{
$path = parse_url($url,PHP_URL_PATH);
Expand Down Expand Up @@ -1863,40 +1880,37 @@ function computeThumbnail($url,$href=false)

if (!$GLOBALS['config']['ENABLE_LOCALCACHE']) return array(); // If local cache is disabled, no thumbnails for services which require the use a local cache.

if ($domain=='flickr.com' || endsWith($domain,'.flickr.com')
|| $domain=='vimeo.com'
|| $domain=='ted.com' || endsWith($domain,'.ted.com')
|| $domain=='xkcd.com' || endsWith($domain,'.xkcd.com')
)
// this could easily go into a config file a la data/options.php, e.g. data/thumbnails.php:
$url_patterns_genthumbnail = array(
// value array becomes the attributes of <img..> 'src' automatically set, all others optional.
'!^https?://(?:www\.)?xkcd\.com(?::\d+)?/.*?/\d+!i'=>array(), // Make sure this URL points to a single comic (/xxx... where xxx is numeric)
'!^https?://(?:www\.)?vimeo\.com(?::\d+)?/.*?/\d+!i'=>array(), // Make sure this vimeo URL points to a video (/xxx... where xxx is numeric)
'!^https?://(?:www\.)?ted\.com(?::\d+)?/talks/!i'=>array(), // Make sure this TED URL points to a video (/talks/...)
'!^https?://(?:www\.)?(flickr)\.com(?::\d+)?/!i'=>array(),
'!^https?://(?:www\.)?(itunes\.apple|imdb)\.com(?::\d+)?/!i'=>array(),
'!^https?://(?:www\.)?(heise|golem|spiegel|sz|nachdenkseiten|netzpolitik)\.de(?::\d+)?/!i'=>array(),
);

$sign = hash_hmac('sha256', $url, $GLOBALS['salt']); // We use the salt to sign data (it's random, secret, and specific to each installation)
foreach($url_patterns_genthumbnail as $pattern=>$img_tpl)
{
if ($domain=='vimeo.com')
{ // Make sure this vimeo URL points to a video (/xxx... where xxx is numeric)
$path = parse_url($url,PHP_URL_PATH);
if (!preg_match('!/\d+.+?!',$path)) return array(); // This is not a single video URL.
if (preg_match($pattern, $url)) {
$img = $img_tpl;
$img['href'] = $href;
$img['src'] = indexUrl().'?do=genthumbnail&hmac='.htmlspecialchars($sign).'&url='.urlencode($url);
$img['alt'] = preg_replace($pattern, empty($img['alt']) ? '\\0 thumbnail' : $img['alt'], $url, 1);
if(empty($img['style'])) $img['style'] = 'max-width:120px; max-height:150px';
return $img;
}
if ($domain=='xkcd.com' || endsWith($domain,'.xkcd.com'))
{ // Make sure this URL points to a single comic (/xxx... where xxx is numeric)
$path = parse_url($url,PHP_URL_PATH);
if (!preg_match('!/\d+.+?!',$path)) return array();
}
if ($domain=='ted.com' || endsWith($domain,'.ted.com'))
{ // Make sure this TED URL points to a video (/talks/...)
$path = parse_url($url,PHP_URL_PATH);
if ("/talks/" !== substr($path,0,7)) return array(); // This is not a single video URL.
}
$sign = hash_hmac('sha256', $url, $GLOBALS['salt']); // We use the salt to sign data (it's random, secret, and specific to each installation)
return array('src'=>indexUrl().'?do=genthumbnail&hmac='.$sign.'&url='.urlencode($url),
'href'=>$href,'width'=>'120','style'=>'height:auto;','alt'=>'thumbnail');
}

// For all other, we try to make a thumbnail of links ending with .jpg/jpeg/png/gif
// Technically speaking, we should download ALL links and check their Content-Type to see if they are images.
// Technically speaking, we should download (or HTTP HEAD) ALL links and check their Content-Type to see if they are images.
// But using the extension will do.
$ext=strtolower(pathinfo($url,PATHINFO_EXTENSION));
if ($ext=='jpg' || $ext=='jpeg' || $ext=='png' || $ext=='gif')
{
$sign = hash_hmac('sha256', $url, $GLOBALS['salt']); // We use the salt to sign data (it's random, secret, and specific to each installation)
return array('src'=>indexUrl().'?do=genthumbnail&hmac='.$sign.'&url='.urlencode($url),
return array('src'=>indexUrl().'?do=genthumbnail&hmac='.htmlspecialchars($sign).'&url='.urlencode($url),
'href'=>$href,'width'=>'120','style'=>'height:auto;','alt'=>'thumbnail');
}
return array(); // No thumbnail.
Expand All @@ -1906,7 +1920,7 @@ function computeThumbnail($url,$href=false)

// Returns the HTML code to display a thumbnail for a link
// with a link to the original URL.
// Understands various services (youtube.com...)
// Understands various services (youtube.com...) - see computeThumbnail(...)
// Input: $url = URL for which the thumbnail must be found.
// $href = if provided, this URL will be followed instead of $url
// Returns '' if no thumbnail available.
Expand Down

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