Move output format detection upwards (chriskacerguis#947)

to allow responses earlier,
i.e. when handling exceptions, which might be thrown in Format::factory, in a REST_Controller subclass.

Author: luckydonald

application/libraries/REST_Controller.php

@@ -507,6 +507,12 @@ public function __construct($config = 'rest')
             $this->{'_'.$this->request->method.'_args'} = [];
         }
 
+        // Which format should the data be returned in?
+        $this->response->format = $this->_detect_output_format();
+
+        // Which language should the data be returned in?
+        $this->response->lang = $this->_detect_lang();
+
         // Now we know all about our request, let's try and parse the body if it exists
         if ($this->request->format && $this->request->body)
         {
@@ -531,12 +537,6 @@ public function __construct($config = 'rest')
             $this->{'_'.$this->request->method.'_args'}
         );
 
-        // Which format should the data be returned in?
-        $this->response->format = $this->_detect_output_format();
-
-        // Which language should the data be returned in?
-        $this->response->lang = $this->_detect_lang();
-
         // Extend this function to apply additional checking early on in the process
         $this->early_checks();