Backend Ajax protocol

Discussion

There should be a standard JSON protocol between the LS backend and Ajax calls to check for errors, permissions and if the user still is logged in. A suggestion would be to wrap $.ajax in a function that checks this for you, like LS.ajax.

All server Ajax calls must return a JSON in the following format:

{
  type: int,
  result: mixed,
  error: {code: int, message: string},
  loggedIn: boolean,
  hasPermission: boolean,
}

Of course there needs to be server side support for this protocol, too, with helper functions to output correct JSON code, e.g. Ajax::outputResult or Ajax::outputError($code, $message).

Preferably, the function should be able to show an error if server throws 500.

Message types

Type	Fields	Description
notloggedin	-	User is not logged in; the login form should appear in a modal and then continue with the action
nopermission	-	No permission
success	success : string	Show success message
error	error : string	Show error message
custom	result : mixed	Custom action, meaning a supplied Javascript function will take care of the response from the server, e.g. feeding HTML to a modal body. BUT: Maybe we could have a message type "modal" which sends modal title, body and footer?

Backbone

Since Javascript library Backbone might be used in the future, it would be nice to know how they handle stuff like this.

Some questions:

• Would we need to duplicate the model code in both backend and frontend?
• How much of the CRUD will happen on client?
• How much would backbone replace Yii and things generated with Gii?

Learning material

TODO

Implementation

A first prototype of the backend classes can be seen here. Instead of a helper, this class can actually be put into LSYiiController, making it available to all controllers in LS.

Example:

public function indexAction()
{
  $this->ajax->outputSucces(gT('Success!'));
}