See also: Emacs behind HTTP proxy
Is it possible to tell emacs to automatically use whatever proxy settings are in use by IE?
The url.el package says I can explicitly specify a proxy like this:
(setq url-using-proxy t)
(setq url-proxy-services '(("http" . "proxyserver:3128")))
Is it possible for this to happen sort of auto-magically, when I change the IE proxy settings?
Yes, it's possible.
The basic idea is to define before-advice for the URL functions, and set those variables to appropriate values. This requires being able to retrieve the IE proxy settings from Windows, from within elisp.
The w32-registry package does this.
Therefore, on Windows, you can do this:
(eval-after-load "url"
'(progn
(require 'w32-registry)
(defadvice url-retrieve (before
w32-set-proxy-dynamically
activate)
"Before retrieving a URL, query the IE Proxy settings, and use them."
(let ((proxy (w32reg-get-ie-proxy-config)))
(setq url-using-proxy proxy
url-proxy-services proxy)))))
If you are handling URL's via browse-url, you can also set it to Windows-specific function like this. Then the URL's will be handled by Windows (invoking your default browser).
browse-url-browser-function is a variable defined in `browse-url.el'.
Its value is browse-url-default-windows-browser
