feat: implement initial read only access

Signed-off-by: Sebastian Krupinski <krupinski01@gmail.com>

lib/Discovery/DiscoveryClient.php

@@ -9,6 +9,11 @@ use RuntimeException;
 class DiscoveryClient
 {
     public function fetch(ServerAddress $server): DiscoveryDocument
+    {
+        return DiscoveryDocument::parse($this->fetchXml($server), $server);
+    }
+
+    public function fetchXml(ServerAddress $server): string
     {
         $curl = curl_init($server->discoveryUrl());
         $xml = '';
@@ -36,7 +41,7 @@ class DiscoveryClient
                 throw new RuntimeException('Discovery returned HTTP ' . $status
                     . ($status === 404 ? '. Enable WOPI and forward /hosting/discovery through the proxy.' : '. Expected HTTP 200; redirects are not followed.'));
             }
-            return DiscoveryDocument::parse($xml, $server);
+            return $xml;
         } finally {
             curl_close($curl);
         }

lib/Discovery/DiscoveryDocument.php

@@ -14,7 +14,7 @@ final readonly class DiscoveryDocument
     public const MAX_BYTES = 2 * 1024 * 1024;
 
     /** @param list<Action> $actions */
-    private function __construct(public array $actions, public bool $hasProofKeys) {}
+    private function __construct(public array $actions, public bool $hasProofKeys, public array $proofKeys = []) {}
 
     public static function parse(string $xml, ServerAddress $server): self
     {
@@ -52,8 +52,14 @@ final readonly class DiscoveryDocument
                 throw new RuntimeException('Discovery has no external view/edit actions. Check WOPI enablement and forwarded HTTPS headers.');
             }
             $proof = $xpath->query('/wopi-discovery/proof-key')->item(0);
+            $keys = [];
+            if ($proof instanceof DOMElement) {
+                foreach (['modulus', 'exponent', 'oldmodulus', 'oldexponent'] as $attribute) {
+                    $keys[$attribute] = $proof->getAttribute($attribute);
+                }
+            }
             return new self($actions, $proof instanceof DOMElement
-                && $proof->getAttribute('modulus') !== '' && $proof->getAttribute('exponent') !== '');
+                && $proof->getAttribute('modulus') !== '' && $proof->getAttribute('exponent') !== '', $keys);
         } finally {
             libxml_clear_errors();
             libxml_use_internal_errors($previous);