How to pass an object to a FatFractal server extension, access from within the extension, and return an object back to client application?

I am using the FatFractal JavaScript SDK and have declared a server extension in my FFDL file as follows:

CREATE EXTENSION /ChangePassword AS javascript:require('scripts/UserAdministration').changePassword();

I am creating a server extension to allow a user to change their login password. From my client application, I want to pass a simple object to /ChangePassword containing the logged in user's username, current (old) password, and new desired password. Assuming I have populated said object, how would I then A) Pass the object the client application to the server extension, B) Get a handle to the passed object in the server extension, and C) Return a confirmation object (preferably) or message from the server extension to the client application once the change is complete?

FFDL:

CREATE OBJECTTYPE ChangePasswordRequest (userName STRING, oldPassword STRING, newPassword STRING)
CREATE COLLECTION /ChangePasswordRequest OBJECTTYPE ChangePasswordRequest

Client application JS code:

    ...

    function ChangePassInfo() {
        this.userName = null;
        this.currentPassword = null;
        this.newPassword = null;
        return this;
    }

    ...

    function changePassword() {
        var uname = ff.loggedInUser().userName;
        var oldPass = $("#input-curr-pass").val();
        var newPass = $("#input-new-pass").val();

        var requestInfo = new ChangePassInfo();
        requestInfo.userName = uname;
        requestInfo.currentPassword = oldPass;
        requestInfo.newPassword = newPass;

        // pass 'requestInfo' to 'ChangePassword' extension
        // acquire handle to confirmation object/message returned from 'ChangePassword'

        ...

    }

Server extension JS code:

var ff = require('ffef/FatFractal');

...

function ChangePasswordRequest() {
    this.clazz = 'ChangePasswordRequest';
    this.createdBy = 'system';
    this.userName = null;
    this.oldPassword = null;
    this.newPassword = null;
    return this;
}

...

function changePassword() {

    var changePassReq; // instance of a 'ChangePasswordRequest' object

    // acquire handle to 'requestInfo' passed from client application to populate 'changePassReq'

    ...

    // return a confirmation message or copy of 'changePassReq' to client application

}

...

exports.changePassword = changePassword;

The commented sections are the problem areas I'm looking to solve. Once those are solved, I should be able to fill in the rest of the implementation. Thanks!

Solution

Let's start with backend. Assuming an object has been posted to the extension, here's how you retrieve it in your function:

var ff = require('ffef/FatFractal');     // FatFractal module
var data = ff.getExtensionRequestData(); // Get request data
var member = data.httpContent.member     // Get 'obj' member of passed object

Alright, so now you've done some stuff and want to return something, here's how you do that:

var r = ff.response();  // Get response object, and populate
r.result = { member: "Something", otherMember: false, yaMember: 42 };
r.responseCode = "200";
r.statusMessage = "This message is useful";
r.mimeType = "application/json";

Finally, to the client side. Here's how to post an object to the extension:

var ff = new FatFractal();

// ...

ff.postObjToExtension({ member: "derp" }, "/yourExtension", ... );

Hope that clarifies things!