Skip to content

Commit

Permalink
[CssSelectorBridge] Move metadata retrieval to lib (#3913)
Browse files Browse the repository at this point in the history 
May become handy for making other bridges
  • Loading branch information
@ORelio
ORelio authored Jan 23, 2024
1 parent b690994 commit feb2a68
Show file tree
Hide file tree
Showing 3 changed files with 258 additions and 250 deletions.
251 changes: 1 addition & 250 deletions bridges/CssSelectorBridge.php
View file
Original file line number Diff line number Diff line change
Expand Up @@ -276,7 +276,7 @@ protected function expandEntryWithSelector($entry_url, $content_selector, $conte
}

$entry_html = getSimpleHTMLDOMCached($entry_url);
$item = $this->entryHtmlRetrieveMetadata($entry_html);
$item = html_find_seo_metadata($entry_html);

if (empty($item['uri'])) {
$item['uri'] = $entry_url;
Expand Down Expand Up @@ -306,253 +306,4 @@ protected function expandEntryWithSelector($entry_url, $content_selector, $conte

return $item;
}

/**
* Retrieve metadata from entry HTML: title, author, date published, etc. from metadata intended for social media embeds and SEO
* @param obj $entry_html DOM object representing the webpage HTML
* @return array Entry data collected from Metadata
*/
protected function entryHtmlRetrieveMetadata($entry_html)
{
$item = [];

// == First source of metadata: Meta tags ==
// Facebook Open Graph (og:KEY) - https://developers.facebook.com/docs/sharing/webmasters
// Twitter (twitter:KEY) - https://developer.twitter.com/en/docs/twitter-for-websites/cards/guides/getting-started
// Standard meta tags - https://www.w3schools.com/tags/tag_meta.asp
// Standard time tag - https://developer.mozilla.org/en-US/docs/Web/HTML/Element/time

// Each Entry field mapping defines a list of possible <meta> tags names that contains the expected value
static $meta_mappings = [
// <meta property="article:KEY" content="VALUE" />
// <meta property="og:KEY" content="VALUE" />
// <meta property="KEY" content="VALUE" />
// <meta name="twitter:KEY" content="VALUE" />
// <meta name="KEY" content="VALUE">
// <link rel="canonical" href="URL" />
'uri' => [
'og:url',
'twitter:url',
'canonical',
],
'title' => [
'og:title',
'twitter:title',
],
'content' => [
'og:description',
'twitter:description',
'description',
],
'timestamp' => [
'article:published_time',
'og:article:published_time',
'releaseDate',
'releasedate',
'article:modified_time',
'og:article:modified_time',
'lastModified',
'lastmodified',
'time',
],
'enclosures' => [
'og:image:secure_url',
'og:image:url',
'og:image',
'twitter:image',
'thumbnailImg',
'thumbnailimg',
],
'author' => [
'article:author',
'og:article:author',
'author',
'article:author:username',
'profile:first_name',
'profile:last_name',
'article:author:first_name',
'article:author:last_name',
'twitter:creator',
],
];

$author_first_name = null;
$author_last_name = null;

// For each Entry property, look for corresponding HTML tags using a list of candidates
foreach ($meta_mappings as $property => $field_list) {
foreach ($field_list as $field) {
// Look for HTML meta tag
$element = null;
if ($field === 'canonical') {
$element = $entry_html->find('link[rel=canonical]');
} else if ($field === 'time') {
$element = $entry_html->find('time[datetime]');
} else {
$element = $entry_html->find("meta[property=$field], meta[name=$field]");
}
// Found something? Extract the value and populate Entry field
if (!empty($element)) {
$element = $element[0];
$field_value = '';
if ($field === 'canonical') {
$field_value = $element->href;
} else if ($field === 'time') {
$field_value = $element->datetime;
} else {
$field_value = $element->content;
}
if (!empty($field_value)) {
if ($field === 'article:author:first_name' || $field === 'profile:first_name') {
$author_first_name = $field_value;
} else if ($field === 'article:author:last_name' || $field === 'profile:last_name') {
$author_last_name = $field_value;
} else {
$item[$property] = $field_value;
break; // Stop on first match, e.g. og:url has priority over canonical url.
}
}
}
}
}

// Populate author from first name and last name if all we have is nothing or Twitter @username
if ((!isset($item['author']) || $item['author'][0] === '@') && (is_string($author_first_name) || is_string($author_last_name))) {
$author = '';
if (is_string($author_first_name)) {
$author = $author_first_name;
}
if (is_string($author_last_name)) {
$author = $author . ' ' . $author_last_name;
}
$item['author'] = trim($author);
}

// == Second source of metadata: Embedded JSON ==
// JSON linked data - https://www.w3.org/TR/2014/REC-json-ld-20140116/
// JSON linked data is COMPLEX and MAY BE LESS RELIABLE than <meta> tags. Used for fields not found as <meta> tags.
// The implementation below will load all ld+json we can understand and attempt to extract relevant information.

// ld+json object types that hold article metadata
// Each mapping define item fields and a list of possible JSON field for this field
// Each candiate JSON field is either a string (field name) or a list (path to nested field)
static $ldjson_article_types = ['webpage', 'article', 'newsarticle', 'blogposting'];
static $ldjson_article_mappings = [
'uri' => ['url', 'mainEntityOfPage'],
'title' => ['headline'],
'content' => ['description'],
'timestamp' => ['dateModified', 'datePublished'],
'enclosures' => ['image'],
'author' => [['author', 'name'], ['author', '@id'], 'author'],
];

// ld+json object types that hold author metadata
$ldjson_author_types = ['person', 'organization'];
$ldjson_author_mappings = []; // ID => Name
$ldjson_author_id = null;

// Utility function for checking if JSON array matches one of the desired ld+json object types
// A JSON object may have a single ld+json @type as a string OR several types at once as a list
$ldjson_is_of_type = function ($json, $allowed_types) {
if (isset($json['@type'])) {
$json_types = $json['@type'];
if (!is_array($json_types)) {
$json_types = [ $json_types ];
}
foreach ($json_types as $item_type) {
if (in_array(strtolower($item_type), $allowed_types)) {
return true;
}
}
}
return false;
};

// Process ld+json objects embedded in the HTML DOM
foreach ($entry_html->find('script[type=application/ld+json]') as $html_ldjson_node) {
$json_raw = json_decode($html_ldjson_node->innertext, true);
if (is_array($json_raw)) {
// The JSON we just loaded may contain directly a single ld+json object AND/OR several ones under the '@graph' key
$json_items = [ $json_raw ];
if (isset($json_raw['@graph'])) {
foreach ($json_raw['@graph'] as $json_raw_sub_item) {
$json_items[] = $json_raw_sub_item;
}
}
// Now that we have a list of distinct JSON items, we can process them individually
foreach ($json_items as $json) {
// JSON item that holds an ld+json Article object (or a variant)
if ($ldjson_is_of_type($json, $ldjson_article_types)) {
// For each item property, look for corresponding JSON fields and populate the item
foreach ($ldjson_article_mappings as $property => $field_list) {
// Skip fields already found as <meta> tags, except Twitter @username (because we might find a better name)
if (!isset($item[$property]) || ($property === 'author' && $item['author'][0] === '@')) {
foreach ($field_list as $field) {
$json_root = $json;
// If necessary, navigate inside the JSON object to access a nested field
if (is_array($field)) {
// At this point, $field = ['author', 'name'] and $json_root = {"author": {"name": "John Doe"}}
$json_navigate_ok = true;
while (count($field) > 1) {
$sub_field = array_shift($field);
if (array_key_exists($sub_field, $json_root)) {
$json_root = $json_root[$sub_field];
if (array_is_list($json_root) && count($json_root) === 1) {
$json_root = $json_root[0]; // Unwrap list of single item e.g. {"author":[{"name":"John Doe"}]}
}
} else {
// Desired path not found in JSON, stop navigating
$json_navigate_ok = false;
break;
}
}
if (!$json_navigate_ok) {
continue; //Desired path not found in JSON, skip this field
}
$field = $field[0];
// At this point, $field = "name" and $json_root = {"name": "John Doe"}
}
// Now we can check for desired field in JSON and populate $item accordingly
if (isset($json_root[$field])) {
$field_value = $json_root[$field];
if (is_array($field_value) && isset($field_value[0])) {
$field_value = $field_value[0]; // Different versions of the same enclosure? Take the first one
}
if (is_string($field_value) && !empty($field_value)) {
if ($property === 'author' && $field === '@id') {
$ldjson_author_id = $field_value; // Author is referred to by its ID: We'll see later if we can resolve it
} else {
$item[$property] = $field_value;
break; // Stop on first match, e.g. {"author":{"name":"John Doe"}} has priority over {"author":"John Doe"}
}
}
}
}
}
}
// JSON item that holds an ld+json Author object (or a variant)
} else if ($ldjson_is_of_type($json, $ldjson_author_types)) {
if (isset($json['@id']) && isset($json['name'])) {
$ldjson_author_mappings[$json['@id']] = $json['name'];
}
}
}
}
}

// Attempt to resolve ld+json author if all we have is nothing or Twitter @username
if ((!isset($item['author']) || $item['author'][0] === '@') && !is_null($ldjson_author_id) && isset($ldjson_author_mappings[$ldjson_author_id])) {
$item['author'] = $ldjson_author_mappings[$ldjson_author_id];
}

// Adjust item field types
if (isset($item['enclosures'])) {
$item['enclosures'] = [ $item['enclosures'] ];
}
if (isset($item['timestamp'])) {
$item['timestamp'] = strtotime($item['timestamp']);
}

return $item;
}
}
1 change: 1 addition & 0 deletions lib/bootstrap.php
View file
Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@
__DIR__ . '/../lib/http.php',
__DIR__ . '/../lib/logger.php',
__DIR__ . '/../lib/url.php',
__DIR__ . '/../lib/seotags.php',
// Vendor
__DIR__ . '/../vendor/parsedown/Parsedown.php',
__DIR__ . '/../vendor/php-urljoin/src/urljoin.php',
Expand Down
Loading

0 comments on commit feb2a68

Please sign in to comment.