I contacted Magnolia a few days back and got help with some code on how to add a plugin into the CKEditor within Magnolia.
I’ve successfully been able to do so, but I had several difficulties, which I’ll outline here:

1) I was unable to extend RichTextFieldFactory

My intention to add additional functionality to the RichTextFieldFactory by extending it failed because the method createFieldComponent.
I wanted to do something like:

        String path = VaadinService.getCurrentRequest().getContextPath();
        config.addPlugin(ABBR_PLUGIN_NAME,path+ ABBR_PLUGIN_PATH);
        richTextEditor = (MagnoliaRichTextField) super.createFieldComponent();
        richTextEditor.setConfig(config);

but it seems that the plugins must be configured during the attach phase of the MagnoliaRichTextField, not sure why, this is the code from RichTextFieldFactory#createFieldComponent :

        richTextEditor = new MagnoliaRichTextField(config) {
            @Override
            public void attach() {
                super.attach();
                String path = VaadinService.getCurrentRequest().getContextPath();
                config.addPlugin(PLUGIN_NAME_MAGNOLIALINK, path + PLUGIN_PATH_MAGNOLIALINK);

                WebBrowser browser = getSession().getBrowser();
                if (browser.isTouchDevice()) {
                    // MGNLUI-1528: Workaround.
                    richTextEditor.setEnabled(false);
                    richTextEditor.setReadOnly(true);
                    richTextEditor.addStyleName("richtextfield-disabled");
                }

            }
        };

When adding the plugin there it worked fine, but it means I can’t extend RichTextFieldFactory because I must recreate the private variable richTextEditor.

2) The plugin file must be in /VAADIN/js/abbr

It was difficult to understand why the field was failing, my only guess was that the file was in the wrong location. It worked when I put it there (/abbr is because of the plugin name). It was not clear that it is necessary for the file to be in that location.

Sometimes, not consistently I would get this error, which is what hinted that the file wasn’t being found:

INFO: Requested resource [/VAADIN/widgetsets/info.magnolia.ui.vaadin.gwt.MagnoliaWidgetSet/ckeditor/plugins/abbr/plugin.js] not found from filesystem or through class loader. Add widgetset and/or theme JAR to your classpath or add files to WebContent/VAADIN folder.

Attachments:
I’ll attach two classes, one is my original – failed - attempt and the successful attempt. Hopefully these are useful.

Regards,

Ricardo