Workaround for buggy servers returning wrong cache-control headers fo…

…r 304 responses
FreshRSS · Sep 20, 2024 · ecee8d4 · ecee8d4
1 parent b18c7d3
commit ecee8d4
Showing 1 changed file with 13 additions and 0 deletions.
diff --git a/src/SimplePie.php b/src/SimplePie.php
@@ -2018,10 +2018,23 @@ protected function fetch_data(&$cache)
                             // is still valid.
                             $this->raw_data = false;
                             if (isset($file)) { // FreshRSS
+                                $old_cache_control = $this->data['headers']['cache-control'] ?? '';
+
                                 // Update cache metadata
                                 $this->data['headers'] = array_map(function (array $values): string {
                                     return implode(',', $values);
                                 }, $file->get_headers());
+
+                                // Workaround for buggy servers returning wrong cache-control headers for 304 responses
+                                if (is_numeric($old_cache_control)) {
+                                    $new_cache_control = $this->data['headers']['cache-control'] ?? '';
+                                    if (!is_numeric($new_cache_control)) {
+                                        $new_cache_control = $this->cache_duration;
+                                    }
+                                    // Allow servers to return a shorter cache duration for 304 responses, but not longer
+                                    $this->data['headers']['cache-control'] = min((int)$old_cache_control, (int)$new_cache_control);
+                                }
+
                                 $this->data['cache_expiration_time'] = \SimplePie\HTTP\Utils::negociate_cache_expiration_time($this->data['headers'] ?? [], $this->cache_duration, $this->cache_duration_min, $this->cache_duration_max);
                             }
                             if (!$cache->set_data($cacheKey, $this->data, $this->cache_duration)) { // FreshRSS