Issue 14370: Improved content negogiation

diff --git a/src/Module/Xrd.php b/src/Module/Xrd.php
index b5cdcce5e7e5d14134771f8f138863b411c069ae..d66bbd00ad9e633b59333e3692a102a826295527 100644 (file)
--- a/src/Module/Xrd.php
+++ b/src/Module/Xrd.php
@@ -34,22 +34,14 @@ class Xrd extends BaseModule
                        }
 
                        $uri = urldecode(trim($_GET['uri']));
-                       if (strpos($_SERVER['HTTP_ACCEPT'] ?? '', 'application/jrd+json') !== false)  {
-                               $mode = Response::TYPE_JSON;
-                       } else {
-                               $mode = Response::TYPE_XML;
-                       }
+                       $mode = self::getAcceptedContentType($_SERVER['HTTP_ACCEPT'] ?? '', Response::TYPE_JSON);
                } else {
                        if (empty($_GET['resource'])) {
                                throw new BadRequestException();
                        }
 
                        $uri = urldecode(trim($_GET['resource']));
-                       if (strpos($_SERVER['HTTP_ACCEPT'] ?? '', 'application/xrd+xml') !== false)  {
-                               $mode = Response::TYPE_XML;
-                       } else {
-                               $mode = Response::TYPE_JSON;
-                       }
+                       $mode = self::getAcceptedContentType($_SERVER['HTTP_ACCEPT'] ?? '', Response::TYPE_XML);
                }
 
                if (substr($uri, 0, 4) === 'http') {
@@ -67,7 +59,7 @@ class Xrd extends BaseModule
                }
 
                if (!empty($host) && $host !== DI::baseUrl()->getHost()) {
-                       DI::logger()->notice('Invalid host name for xrd query',['host' => $host, 'uri' => $uri]);
+                       DI::logger()->notice('Invalid host name for xrd query', ['host' => $host, 'uri' => $uri]);
                        throw new NotFoundException('Invalid host name for xrd query: ' . $host);
                }
 
@@ -102,6 +94,36 @@ class Xrd extends BaseModule
                }
        }
 
+       /**
+        * Detect the accepted content type.
+        * @todo Handle priorities (see "application/xrd+xml,text/xml;q=0.9")
+        *
+        * @param string $accept
+        * @param string $default
+        * @return string
+        */
+       private function getAcceptedContentType(string $accept, string $default): string
+       {
+               $parts = [];
+               foreach (explode(',', $accept) as $part) {
+                       $parts[] = current(explode(';', $part));
+               }
+
+               if (empty($parts)) {
+                       return $default;
+               } elseif (in_array('application/jrd+json', $parts) && !in_array('application/xrd+xml', $parts)) {
+                       return Response::TYPE_JSON;
+               } elseif (!in_array('application/jrd+json', $parts) && in_array('application/xrd+xml', $parts)) {
+                       return Response::TYPE_XML;
+               } elseif (in_array('application/json', $parts) && !in_array('text/xml', $parts)) {
+                       return Response::TYPE_JSON;
+               } elseif (!in_array('application/json', $parts) && in_array('text/xml', $parts)) {
+                       return Response::TYPE_XML;
+               } else {
+                       return $default;
+               }
+       }
+
        private function printSystemJSON(array $owner)
        {
                $baseURL = (string)$this->baseUrl;