Fix showing owner of shared calendars on iOS

lib/CalDAV/Backend/PDO.php

@@ -192,9 +192,13 @@ public function getCalendarsForUser($principalUri)
             $calendar['share-access'] = (int) $row['access'];
             // 1 = owner, 2 = readonly, 3 = readwrite
             if ($row['access'] > 1) {
-                // We need to find more information about the original owner.
-                //$stmt2 = $this->pdo->prepare('SELECT principaluri FROM ' . $this->calendarInstancesTableName . ' WHERE access = 1 AND id = ?');
-                //$stmt2->execute([$row['id']]);
+                $ownerStmt = $this->pdo->prepare("SELECT principaluri FROM {$this->calendarInstancesTableName} WHERE access = 1 AND calendarid = ?");
+                $ownerStmt->execute([$row['calendarid']]);
+
+                $ownerRow = $ownerStmt->fetch(\PDO::FETCH_ASSOC);
+                if ($ownerRow && is_array($ownerRow) && array_key_exists('principaluri', $ownerRow)) {
+                    $calendar['owner-principal'] = $ownerRow['principaluri'];
+                }
 
                 // read-only is for backwards compatibility. Might go away in
                 // the future.

lib/CalDAV/Principal/User.php

@@ -131,6 +131,22 @@ public function getACL()
             'protected' => true,
         ];
 
+        /**
+         * Members of shared calendars needs to be able to read information about the owner.
+         * 
+         * The Principal has no knowledge about the calendars and therefore it is not 
+         * possible to limit the access to members of a shared calendar 
+         * in DAVACL/Plugin.php getCurrentUserPrivilegeSet.
+         * 
+         * As workaround all authenticated users are getting the read privilege for other users.
+         */
+
+         $acl[] = [
+            'privilege' => '{DAV:}read',
+            'principal' => '{DAV:}authenticated',
+            'protected' => true,
+        ];
+
         return $acl;
     }
 }

lib/CalDAV/SharedCalendar.php

@@ -216,4 +216,16 @@ public function getChildACL()
 
         return $acl;
     }
+
+    /**
+     * Returns the 'original owner principal' for this shared resource.
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    public function getOwnerPrincipal()
+    {
+        return isset($this->calendarInfo['owner-principal']) ? $this->calendarInfo['owner-principal'] : $this->getOwner();
+    }
 }

lib/CalDAV/SharingPlugin.php

@@ -86,7 +86,7 @@ public function initialize(DAV\Server $server)
         $this->server->xml->elementMap['{'.Plugin::NS_CALENDARSERVER.'}share'] = \Sabre\CalDAV\Xml\Request\Share::class;
         $this->server->xml->elementMap['{'.Plugin::NS_CALENDARSERVER.'}invite-reply'] = \Sabre\CalDAV\Xml\Request\InviteReply::class;
 
-        $this->server->on('propFind', [$this, 'propFindEarly']);
+        $this->server->on('propFind', [$this, 'propFindEarly'], 10);
         $this->server->on('propFind', [$this, 'propFindLate'], 150);
         $this->server->on('propPatch', [$this, 'propPatch'], 40);
         $this->server->on('method:POST', [$this, 'httpPost']);
@@ -106,6 +106,14 @@ public function propFindEarly(DAV\PropFind $propFind, DAV\INode $node)
                     $node->getInvites()
                 );
             });
+
+            // Needs to be called before ACL
+            $propFind->handle('{DAV:}owner', function () use ($node) {
+                $shareAccess = $node->getShareAccess();
+                if ($shareAccess > 1) {
+                    return new \Sabre\DAV\Xml\Property\Href($node->getOwnerPrincipal() . '/');
+                }
+            });
         }
     }
 

lib/DAV/Sharing/ISharedNode.php

@@ -66,4 +66,13 @@ public function updateInvites(array $sharees);
      * @return \Sabre\DAV\Xml\Element\Sharee[]
      */
     public function getInvites();
+
+    /**
+     * Returns the 'original owner principal' for this shared resource.
+     *
+     * This must be a url to a principal, or null if there's no owner
+     *
+     * @return string|null
+     */
+    public function getOwnerPrincipal();
 }