rss-bridge/lib/FeedParser.php

264 lines
9.2 KiB
PHP

<?php
declare(strict_types=1);
/**
* Very basic and naive feed parser.
*
* Scrapes out rss 0.91, 1.0, 2.0 and atom 1.0.
*
* Produce arrays meant to be used inside rss-bridge.
*
* The item structure is tweaked so that works with FeedItem
*/
final class FeedParser
{
public function parseFeed(string $xmlString): array
{
libxml_use_internal_errors(true);
$xml = simplexml_load_string(trim($xmlString));
$xmlErrors = libxml_get_errors();
libxml_use_internal_errors(false);
if ($xml === false) {
if ($xmlErrors) {
$firstXmlErrorMessage = $xmlErrors[0]->message;
}
throw new \Exception(sprintf('Unable to parse xml: %s', $firstXmlErrorMessage ?? ''));
}
$feed = [
'title' => null,
'uri' => null,
'icon' => null,
'items' => [],
];
if (isset($xml->item[0])) {
// rss 1.0
$channel = $xml->channel[0];
$feed['title'] = trim((string)$channel->title);
$feed['uri'] = trim((string)$channel->link);
if (!empty($channel->image)) {
$feed['icon'] = trim((string)$channel->image->url);
}
foreach ($xml->item as $item) {
$feed['items'][] = $this->parseRss1Item($item);
}
} elseif (isset($xml->channel[0])) {
// rss 2.0
$channel = $xml->channel[0];
$feed['title'] = trim((string)$channel->title);
$feed['uri'] = trim((string)$channel->link);
if (!empty($channel->image)) {
$feed['icon'] = trim((string)$channel->image->url);
}
foreach ($channel->item as $item) {
$feed['items'][] = $this->parseRss2Item($item);
}
} elseif (isset($xml->entry[0])) {
// atom 1.0
$feed['title'] = (string)$xml->title;
// Find best link (only one, or first of 'alternate')
if (!isset($xml->link)) {
$feed['uri'] = '';
} elseif (count($xml->link) === 1) {
$feed['uri'] = (string)$xml->link[0]['href'];
} else {
$feed['uri'] = '';
foreach ($xml->link as $link) {
if (strtolower((string) $link['rel']) === 'alternate') {
$feed['uri'] = (string)$link['href'];
break;
}
}
}
if (!empty($xml->icon)) {
$feed['icon'] = (string)$xml->icon;
} elseif (!empty($xml->logo)) {
$feed['icon'] = (string)$xml->logo;
}
foreach ($xml->entry as $item) {
$feed['items'][] = $this->parseAtomItem($item);
}
} else {
throw new \Exception('Unable to detect feed format');
}
return $feed;
}
public function parseAtomItem(\SimpleXMLElement $feedItem): array
{
$item = $this->parseRss2Item($feedItem);
if (isset($feedItem->id)) {
$item['uri'] = (string)$feedItem->id;
}
if (isset($feedItem->title)) {
$item['title'] = html_entity_decode((string)$feedItem->title);
}
if (isset($feedItem->updated)) {
$item['timestamp'] = strtotime((string)$feedItem->updated);
}
if (isset($feedItem->author)) {
$item['author'] = (string)$feedItem->author->name;
}
if (isset($feedItem->content)) {
$contentChildren = $feedItem->content->children();
if (count($contentChildren) > 0) {
$content = '';
foreach ($contentChildren as $contentChild) {
$content .= $contentChild->asXML();
}
$item['content'] = $content;
} else {
$item['content'] = (string)$feedItem->content;
}
}
// When "link" field is present, URL is more reliable than "id" field
if (count($feedItem->link) === 1) {
$item['uri'] = (string)$feedItem->link[0]['href'];
} else {
foreach ($feedItem->link as $link) {
if (strtolower((string) $link['rel']) === 'alternate') {
$item['uri'] = (string)$link['href'];
}
if (strtolower((string) $link['rel']) === 'enclosure') {
$item['enclosures'][] = (string)$link['href'];
}
}
}
return $item;
}
public function parseRss2Item(\SimpleXMLElement $feedItem): array
{
$item = [
'uri' => '',
'title' => '',
'content' => '',
'timestamp' => '',
'author' => '',
//'uid' => null,
//'categories' => [],
//'enclosures' => [],
];
foreach ($feedItem as $k => $v) {
$hasChildren = count($v) !== 0;
if (!$hasChildren) {
$item[$k] = (string) $v;
}
}
if (isset($feedItem->link)) {
// todo: trim uri
$item['uri'] = (string)$feedItem->link;
}
if (isset($feedItem->title)) {
$item['title'] = html_entity_decode((string)$feedItem->title);
}
if (isset($feedItem->description)) {
$item['content'] = (string)$feedItem->description;
}
$namespaces = $feedItem->getNamespaces(true);
if (isset($namespaces['dc'])) {
$dc = $feedItem->children($namespaces['dc']);
}
if (isset($namespaces['media'])) {
$media = $feedItem->children($namespaces['media']);
}
foreach ($namespaces as $namespaceName => $namespaceUrl) {
if (in_array($namespaceName, ['', 'content', 'media'])) {
continue;
}
$module = $feedItem->children($namespaceUrl);
$item[$namespaceName] = [];
foreach ($module as $moduleKey => $moduleValue) {
$item[$namespaceName][$moduleKey] = (string) $moduleValue;
}
}
if (isset($namespaces['itunes'])) {
$enclosure = $feedItem->enclosure;
$item['enclosure'] = [
'url' => (string) $enclosure['url'],
'length' => (string) $enclosure['length'],
'type' => (string) $enclosure['type'],
];
}
if (isset($feedItem->guid)) {
// Pluck out a url from guid
foreach ($feedItem->guid->attributes() as $attribute => $value) {
if (
$attribute === 'isPermaLink'
&& (
$value === 'true' || (
filter_var($feedItem->guid, FILTER_VALIDATE_URL)
&& (empty($item['uri']) || !filter_var($item['uri'], FILTER_VALIDATE_URL))
)
)
) {
$item['uri'] = (string)$feedItem->guid;
break;
}
}
}
if (isset($feedItem->pubDate)) {
$item['timestamp'] = strtotime((string)$feedItem->pubDate);
} elseif (isset($dc->date)) {
$item['timestamp'] = strtotime((string)$dc->date);
}
if (isset($feedItem->author)) {
$item['author'] = (string)$feedItem->author;
} elseif (isset($feedItem->creator)) {
$item['author'] = (string)$feedItem->creator;
} elseif (isset($dc->creator)) {
$item['author'] = (string)$dc->creator;
} elseif (isset($media->credit)) {
$item['author'] = (string)$media->credit;
}
if (isset($feedItem->enclosure) && !empty($feedItem->enclosure['url'])) {
$item['enclosures'] = [
(string)$feedItem->enclosure['url'],
];
}
return $item;
}
public function parseRss1Item(\SimpleXMLElement $feedItem): array
{
$item = [
'uri' => '',
'title' => '',
'content' => '',
'timestamp' => '',
'author' => '',
//'uid' => null,
//'categories' => [],
//'enclosures' => [],
];
if (isset($feedItem->link)) {
// todo: trim uri
$item['uri'] = (string)$feedItem->link;
}
if (isset($feedItem->title)) {
$item['title'] = html_entity_decode((string)$feedItem->title);
}
if (isset($feedItem->description)) {
$item['content'] = (string)$feedItem->description;
}
$namespaces = $feedItem->getNamespaces(true);
if (isset($namespaces['dc'])) {
$dc = $feedItem->children($namespaces['dc']);
if (isset($dc->date)) {
$item['timestamp'] = strtotime((string)$dc->date);
}
if (isset($dc->creator)) {
$item['author'] = (string)$dc->creator;
}
}
return $item;
}
}