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Super-basic OpenGraph image preview support, "works for me"

This commit is contained in:
Mikael Nordfeldth 2016-01-12 15:29:03 +01:00
parent f4feef477b
commit 3658774429
2 changed files with 71 additions and 3 deletions
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6
plugins/Oembed/OembedPlugin.php
View File

@ -40,16 +40,16 @@ class OembedPlugin extends Plugin
try {
common_log(LOG_INFO, 'Trying to discover an oEmbed endpoint using link headers.');
$api = oEmbedHelper::oEmbedEndpointFromHTML($dom);
common_log(LOG_INFO, 'Found API endpoint ' . $api . ' for URL ' . $url);
common_log(LOG_INFO, 'Found oEmbed API endpoint ' . $api . ' for URL ' . $url);
$params = array(
'maxwidth' => common_config('thumbnail', 'width'),
'maxheight' => common_config('thumbnail', 'height'),
);
$metadata = oEmbedHelper::getOembedFrom($api, $url, $params);
} catch (Exception $e) {
common_log(LOG_INFO, 'Could not find an oEmbed endpoint using link headers.');
common_log(LOG_INFO, 'Could not find an oEmbed endpoint using link headers, trying OpenGraph from HTML.');
// Just ignore it!
$metadata = OpenGraphHelper::ogFromHtml($dom);
}
}

68
plugins/Oembed/lib/opengraphhelper.php Normal file
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@ -0,0 +1,68 @@
<?php
if (!defined('GNUSOCIAL')) { exit(1); }
/**
* Utility class to get OpenGraph data from HTML DOMs etc.
*/
class OpenGraphHelper
{
const KEY_REGEX = '/^og\:(\w+)(?:\:(\w+))?/';
protected static $property_map = [
'site_name' => 'provider_name',
'title' => 'title',
'description' => 'html',
'type' => 'type',
'url' => 'url',
'image' => 'thumbnail_url',
];
// This regex map has: /pattern(match)/ => matchindex | string
protected static $type_regex_map = [
'/^(video)/' => 1,
'/^image/' => 'photo',
];
static function ogFromHtml(DOMDocument $dom) {
$obj = new stdClass();
$nodes = $dom->getElementsByTagName('meta');
for ($i = 0; $i < $nodes->length; $i++) {
$node = $nodes->item($i);
if (!$node->hasAttributes()) {
continue;
}
$property = $node->attributes->getNamedItem('property');
$matches = array();
if (!preg_match(self::KEY_REGEX, $property->value, $matches)) {
// not property="og:something"
continue;
}
if (!isset(self::$property_map[$matches[1]])) {
// unknown metadata property, nothing we would care about anyway
continue;
}
$prop = self::$property_map[$matches[1]];
$obj->{$prop} = $node->attributes->getNamedItem('content')->value;
// I don't care right now if they're empty
}
if (isset($obj->type)) {
// Loop through each known OpenGraph type where we have a match in oEmbed
foreach (self::$type_regex_map as $pattern=>$replacement) {
$matches = array();
if (preg_match($pattern, $obj->type, $matches)) {
$obj->type = is_int($replacement)
? $matches[$replacement]
: $replacement;
break;
}
}
// If it's not known to our type map, we just pass it through in hopes of it getting handled anyway
} elseif (isset($obj->url)) {
// If no type is set but we have a URL, let's set type=link
$obj->type = 'link';
}
return $obj;
}
}