helm-dash on windows and viewing docs inside emacs

Question

I am trying to get helm-dash to work on Windows and I want to view the docsets in emacs. Here is what I did so far:

• downloaded ZealPortable (I don't have admin rights)
• downloaded some docs
• pointed helm-dash-docsets-path to the docsets folder
• activate at least one docset

when I now invoke helm-dash and search for a function, the docset opens in the default browser.
What I want is to view the docsets inside emacs. For that I can set the handy variable helm-dash-browser-func to eww.
Problem: eww is not able to resolve URLs to local files. At least for me. It interprets the c: in the path as the hostname.
Has anyone ever stumbled upon that issue? Is there a way to solve it? Perhaps a different browser than eww?

Btw.: I'm using spacemacs but that shouldn't make any difference, should it?

Answer 1

I think the url package is not handling Windows pathnames well. We can try to fix it.

(defun url-generic-parse-url-fix-windows-path (fn url)
  (if (or (not (stringp url))
          (not (string-match "\\`file://\\(\\([a-z]\\):\\)/" url)))
      (funcall fn url)
    (let ((drive (match-string 2 url))
          (clx (funcall fn (replace-match "/\\2" t nil url 1))))
      (setf (url-filename clx)
            (concat drive ":" (substring (url-filename clx) 2)))
      clx)))

(advice-add 'url-generic-parse-url :around #'url-generic-parse-url-fix-windows-path)
(url-generic-parse-url "file://c:/foo")
;; => [cl-struct-url "file" nil nil "" nil "c:/foo" nil nil t nil t]

(advice-remove 'url-generic-parse-url #'url-generic-parse-url-fix-windows-path)
(url-generic-parse-url "file://c:/foo")
;; => [cl-struct-url "file" nil nil "c" nil "/foo" nil nil t nil t]

See, if that works for you (I have no access to such a machine right now.).