Mentions plugin cache

[mlewand]

Are you reporting a feature request or a bug?

Feature request

Provide detailed reproduction steps (if any)

Mentions responses should be cached.

Currently there's an issue that each typed character after initial mention match causes a HTTP query. That would result with a terrible performance.

Take this case as an example:

1. Create editor with below code:

CKEDITOR.replace( 'editor', {
	width: 600,
	mentions: [ {
		feed: 'feed.json?query={encodedQuery}',
		minChars: 1,
		marker: '@'
	} ],
	startupFocus: true
} );

2. This is optional but you might want to create a dummy feed.json file.
3. Type "@sampleContent" in the editor, and then use backspace to remove some characters.

Expected result

Mentions plugin caches the previous answers.

The cache should be implemented based on URL requested (ofc final url, meaning that it should consider template output). Also it is important to note that the cache should be shared globally across all of the instances.

Actual result

Each trigger causes a HTTP request. Here's inspector showing the requests:

Other details

• Browser: …
• OS: …
• CKEditor version: …
• Installed CKEditor plugins: …

[mlewand]

Closed with #1977.