Detection of non-unique GUIDs (#1887)

* Detection of non-unique GUIDs

Some feeds are using GUIDs, but fail to make them unique.
Example: https://www.kbh-sprogcenter.dk/en/category/danish-break/feed/
This patch detects non-unique GUIDs, and disable GUIDs in that specific
case.

* Add state and log

app/Models/Feed.php

@@ -335,6 +335,8 @@ class FreshRSS_Feed extends Minz_Model {
 
 	public function loadEntries($feed) {
 		$entries = array();
+		$guids = array();
+		$hasUniqueGuids = true;
 
 		foreach ($feed->get_items() as $item) {
 			$title = html_only_entity_decode(strip_tags($item->get_title()));
@@ -375,9 +377,13 @@ class FreshRSS_Feed extends Minz_Model {
 				}
 			}
 
+			$guid = $item->get_id(false, false);
+			$hasUniqueGuids &= empty($guids['_' . $guid]);
+			$guids['_' . $guid] = true;
+
 			$entry = new FreshRSS_Entry(
 				$this->id(),
-				$item->get_id(false, false),
+				$guid,
 				$title === null ? '' : $title,
 				$author === null ? '' : html_only_entity_decode(strip_tags($author->name == null ? $author->email : $author->name)),
 				$content === null ? '' : $content,
@@ -392,6 +398,23 @@ class FreshRSS_Feed extends Minz_Model {
 			unset($item);
 		}
 
+		$hasBadGuids = $this->attributes('hasBadGuids');
+		if ($hasBadGuids != !$hasUniqueGuids) {
+			$hasBadGuids = !$hasUniqueGuids;
+			if ($hasBadGuids) {
+				Minz_Log::warning('Feed has invalid GUIDs: ' . $this->url);
+			} else {
+				Minz_Log::warning('Feed has valid GUIDs again: ' . $this->url);
+			}
+			$feedDAO = FreshRSS_Factory::createFeedDao();
+			$feedDAO->updateFeedAttribute($this, 'hasBadGuids', $hasBadGuids);
+		}
+		if (!$hasUniqueGuids) {
+			foreach ($entries as $entry) {
+				$entry->_guid('');
+			}
+		}
+
 		$this->entries = $entries;
 	}