API to get dialog's subject of change / model

[mlewand]

Are you reporting a feature request or a bug?

Feature request

Provide detailed reproduction steps (if any)

Currently there's no common way to access a subject of change for a dialog, instead each dialog implements this in a custom way.

Having this unified would allow us to add a method like dialog.isEditing() that tells whether a new entity is currently created or an existing one is created. We often need this kind of information.

Note that since the dialogs are static, isEditing method would need to accept editor instance as an argument.

Proposal

Add a new interface that might be implemented in dialogDefinition, let's call it ModeledDialog.

It features a single method:

• getModel( editor ) : [Object/null]
  • For the most plugins like table / link it would simply return a CKEDITOR.dom.element if there's a related element to it. For widget plugins (image2, placeholder) it would return widget instance that is a subject of this dialog.
  • Returns null if there's no related model (about, help dialogs).

If the dialog does not implement getModel() it is assumed to be always in editing mode (backward compatible).

Compatibility

Compatibility is a priority here. In case we have some workarounds in published plugins, like:

• Adding a widget to dialog event in image2 plugin
• Passing widget instance as a first argument to CKEDITOR.dialog.definition.uiElement#setup() method.

[mlewand]

Let's start the discussion first to understand what's the best direction here. I came up with this proposition while reviewing #2277 - as we need an information whether the dialog is editing something or adding.

[jacekbogdanski]

I'm wondering if we need a function returning model. Could't be just isEditing function returning true as a default to overwrite?

However, we already have a request for putting a widget into dialog events (#1044) so it looks like this feature may not be redundant.

It may play nice with #2277 where the new feature will be enabled if plugin or widget is adapted to it, ie. implements getModel function.

Can we assume that model existence is synonymous with isEditing mode? I don't see a problem with our plugins / widgets, but maybe there are cases where this mode should be set explicitly?

[mlewand]

The function for returning the model is needed anyway so it make sense to add it. What's more is that if you implement getModel you don't have to implement isEditing function anymore (as long as generic implementation covers handling of common types, such as DOM elements, widgets etc.).

[jacekbogdanski]

I'm wondering if we could also enable definition name with this feature. It seems like the name is hidden under dialog internals, but getModel function gives a lot of options to handle special cases for the given plugins. As an example:

editor.on( 'dialogHide', function( evt ) {
  var dialog = evt.data;
  // Plugin name hidden under private object,
  // we could make it accessible from `dialog.name`
  if ( dialog._.name === 'link' ) {
    var link = dialog.getModel();
    link.data( 'tracking-id', generateTrackingId( link.getAttribute( 'href' ) );
  }
} );

Similar feature request was already asked here: #2669