Prepare params via server side for plupload

Question

I am using Plupload and would like to prepare the parameters server side. Below is an example of how I want to accomplish this:

$.post("prepare.php", function(data){
   // data put into post array;
   preparedParams = post[0];
   additionalParams = post[1];
}

var uploader = new plupload.Uploader({
        preinit : {
            // some stuff here
        },
        runtimes : thisRunTime,
        browse_button : 'pickfiles',
        container : 'container',
        url : preparedURL,
        multipart_params: {
            preparedParams
        },
        file_data_name: 'file',
        additionalParams
    });

How can I make this work?

Answer 1

What I ended up doing was encoding the parameters to json via serverside (PHP). The final setup looks like this:

$.post("prepare.php", function(data){
   setup(data);
}

function setup(params){
   var JSONData = JSON.parse(params);
   var uploader = new plupload.Uploader({
        preinit : {
            // some stuff here
        },
        runtimes : thisRunTime,
        browse_button : 'pickfiles',
        container : 'container',
        url : preparedURL,
        multipart_params : JSONData,
        file_data_name: 'file',
        additionalParams
    });
}