NonGNU ELPA - engine-mode

engine-mode is available on MELPA.

Using use-package:

(use-package engine-mode
  :ensure t

  :config
  (engine-mode t))

You can also install it like any other elisp file by adding it to your load path and globally enabling it:

(require 'engine-mode)
(engine-mode t)

engine-mode uses the engine/browser-function variable to determine which browser it should use to open the URL it constructs. To change the default browser, redefine engine/browser-function. For example, to always use Emacs' built-in eww browser:

(setq engine/browser-function 'eww-browse-url)

engine/browser-function defaults to browse-url-browser-function, which Emacs uses globally to open links.

The implementation of the browse-url-browser-function variable contains a comprehensive list of possible browser functions. You can get to that by hitting C-h v browse-url-browser-function <RETURN> and following the link to browse-url.el.

To only change the browser for a single engine, use the :browser keyword argument when you define the engine. For example, to use eww only for your GitHub search results, try:

(defengine github
  "https://github.com/search?ref=simplesearch&q=%s"
  :browser 'eww-browse-url)

As mentioned about, see the implementation of the browse-url-browser-function for a definitive list of browsers.

The default keymap prefix for engine-mode is C-x /. If you'd like to bind the keymap to an additional prefix (say, C-c s), you totally can:

(engine/set-keymap-prefix (kbd "C-c s"))

If you use use-package, you can achieve the same thing with:

:bind-keymap ("C-c s" . engine-mode-prefixed-map)

defengine assigns each engine a reasonable default docstring, but you can override that on a case-by-case basis with the :docstring keyword argument:

(defengine ctan
  "https://www.ctan.org/search/?x=1&PORTAL=on&phrase=%s"
  :docstring "Search the Comprehensive TeX Archive Network (ctan.org)")

An engine might want to transform a search term in some way before it interpolates the term into the URL. Maybe the term should have a different encoding, or be capitalized differently, or, uh, be passed through ROT13. Whatever the reason, you can apply a custom transformation to a search term by passing a function to defengine through the :term-transformation-hook keyword argument.

For example, to UPCASE all of your DuckDuckGo searches:

(defengine duckduckgo
  "https://duckduckgo.com/?q=%s"
  :term-transformation-hook upcase)

Or, to ensure that all your queries are encoded as latin-1:

(defengine diec2
  "dlc.iec.cat/results.asp?txtEntrada=%s"
  :term-transformation-hook (lambda (term) (encode-coding-string term latin-1))
  :keybinding "c")

Since many browsers save keyword searches using the same format as engine-mode (that is, by using %s in a url to indicate a search term), it's not too hard to import them into Emacs.

@sshaw has written a script to import from Chrome on OS X. Thanks for that!