[fw-general] Zend_Controller_Action_Helper_Json content type problem

[Juan Felipe Alvarez Saldarriaga]

Hey!

I was trying to upload a file ala "ajax" (via iframe) using jquery
form plugin (http://malsup.com/jquery/form/#file-upload), this plugin
use the iframe technique to upload files and then get the response
printed in the iframe, what's the problem? by default the json action
helper sets the content-type header to application/json and when the
response is sent a download popup shows up with the json string, seems
like you can't override the default content-type :S so I fix it with
this:

public action loadFileAction()
{
        if ( true === empty( $_FILES["archivo"]["tmp_name"] ) )
        {
            Ceiba_Error::getInstance()->add( "Por favor agregue un archivo" );

            $data = Zend_Json::encode( array( "errors" =>
Ceiba_Error::getInstance()->getErrors() ) );

            $this->getResponse()->setHeader( "Content-Type", "text/plain" )
                ->setBody( $data );
                // ->sendResponse();

            return true;
        }
}

How to override the default json action helper content-type header?
would be nice to add a setter to achive this.

Thanks.