Base on paste event,
1. Automatically upload images.
2. Automatically upload image url (parse html get '<img>' src to backend download, will return a new image url).
1. download plugin(https://ckeditor.com/cke4/addon/pasteUploadImage)
2. copy to ckeditor/plugins category
3. edit ckeditor/config.js:
// required
1) config.extraPlugins = 'pasteUploadImage';
// required
2) config.pasteUploadFileApi = 'api';
// optional
3) config.pasteUploadImageUrlApi = 'api';
// pastefromword must add '?'
4) config.filebrowserImageUploadUrl = '/api?';
If you not config 3), will use 1) to instead it.
4. FormData filename = 'upload'
5. uploaded result:
data = {
filename: '',
url: 'new url',
uploaded: 1
}