(added for code hosting)

Motivation

This is a WIP branch of emacs that adds support for content blocking, e.g. blocks loading external resources in WebKit. The primary motivation for me is to block privacy tracking images from my email. Currently, this only works on MacOS since that’s all I really have access to; help for making this work on GTK WebKit would be awesome.

Expect this to be constantly rebased!

While this is pretty neat, I don’t have the time to work on finishing the linux branch of this.

TODOs

• [ ] Check if I correctly cleaned up C memory
• [ ] Add GTK version
• [ ] Sign FSF paperwork, if need be
• [ ] Discuss API design of passing a new parameter for content rules

Should we put this in args instead of a new function parameter? Or maybe we should restrict the API to just be a boolean of block/don’t block?

• [ ] Implement a ‘remove content blocker rules and reload’ function

This is a bit blocked by the above.

mu4e example

This is the current way I’m using this in mu4e:

;; add support for xwidgets if available
(when (featurep 'xwidget-internal)
  (defun smf/mu4e-action-view-with-xwidget (msg)
    "View the body of MSG inside xwidget-webkit.
This is only available in Emacs 25+; also see the discussion of
privacy aspects in `(mu4e) Displaying rich-text messages'."
    (unless (fboundp 'xwidget-webkit-browse-url)
      (mu4e-error "No xwidget support available"))
    (xwidget-webkit-browse-url-block-ext ;; blocks external resources
     (concat "file://" (mu4e~write-body-to-html msg)) t))

  (add-to-list 'mu4e-view-actions
               '("xViewXWidget" . smf/mu4e-action-view-with-xwidget) t))

Or you can be even more fancy and use cl-flet

(defun smf/mu4e-block-content (orig-fn &rest args)
  (cl-letf* ((old-xwidget-webkit-browse-url
              (symbol-function 'xwidget-webkit-browse-url))
             ((symbol-function 'xwidget-webkit-browse-url)
              (lambda (url &optional new-session &rest _ignore)
                (funcall old-xwidget-webkit-browse-url url new-session t)))
             (old-xwidget-webkit-goto-url
              (symbol-function 'xwidget-webkit-goto-url))
             ((symbol-function 'xwidget-webkit-goto-url)
              (lambda (url &optional block-content)
                (funcall old-xwidget-webkit-goto-url url t))))
    (apply orig-fn args)))

(advice-add #'mu4e-action-view-with-xwidget :around #'smf/mu4e-block-content)
(add-to-list 'mu4e-view-actions '("xWidget" . mu4e-action-view-with-xwidget) t)

State

This current state is “works for me.”

Before the patch

After the patch