magit-log-browse-github-commit.el

;; Adapted from https://gist.github.com/ieure/883725 for magit-log
(eval-after-load "magit"
  '(progn
     (defun magit-log-browse-github-commit (commit)
       "Open a browser pointing to the current commit on GitHub.

        With prefix argument, go to the commit HEAD is at."
       (interactive "p")
       (let* ((branch (magit-get-current-branch))
              (remote (and branch (magit-get "branch" branch "remote")))
              (remote-url (magit-get "remote" remote "url"))
              (current-commit (magit-commit-at-point)))

         (browse-url
          (cond ((string-match "git@github\\.com" remote-url)
                 (replace-regexp-in-string
                  "^git@github.com:\\(.*?\\)\\(\\.git\\)?$"
                  (format "https://github.com/\\1/commit/%s" current-commit)
                  remote-url))
                ((string-match "https?://github\\.com" remote-url)
                 (replace-regexp-in-string
                  "^\\(https?://github\\.com/.*?\\)\\(\\.git\\)?$"
                  (format "\\1/commit/%s" current-commit) remote-url))
                (t (error "Tracked branch is not on GitHub."))))))

     (define-key magit-log-mode-map "\C-cb" 'magit-log-browse-github-commit)))