Tell the user they cannot use the networking support if they have not...

Tell the user they cannot use the networking support if they have not installed the appropriate PHP modules

htdocs/admin/site/networking.php

@@ -35,6 +35,21 @@ require_once('pieforms/pieform.php');
 require_once('searchlib.php');
 define('TITLE', get_string('networking', 'admin'));
 
+$opensslext = extension_loaded('openssl');
+$curlext    = extension_loaded('curl');
+$xmlrpcext  = extension_loaded('xmlrpc');
+
+if (!$opensslext || !$curlext || !$xmlrpcext) {
+    $smarty = smarty();
+    $missingextensions = array();
+    !$opensslext && $missingextensions[] = 'openssl';
+    !$curlext    && $missingextensions[] = 'curl';
+    !$xmlrpcext  && $missingextensions[] = 'xmlrpc';
+    $smarty->assign('missingextensions', $missingextensions);
+    $smarty->display('admin/networking.tpl');
+    exit;
+}
+
 $openssl = OpenSslRepo::singleton();
 
 $yesno = array(true  => get_string('yes'),