Tiny proxy to redirect Yahoo searches from the Safari search bar to DuckDuckGo

.htaccess

Options +ExecCGI +FollowSymLinks

RewriteEngine On
RewriteRule ^search duckduckgo.rb

duckduckgo.rb

#!/usr/bin/env ruby -w

=begin

For this to work, add the following line to /etc/hosts:

127.0.0.1 search.yahoo.com

Searches using 'Yahoo' in the Safari search bar will now redirect to DuckDuckGo (or somewhere else if you change REPLACEMENT_URL). You can still search Yahoo directly at www.yahoo.com.

=end

require 'cgi'

REPLACEMENT_URL = 'https://duckduckgo.com/?q=%s'
ALT_YAHOO_SERVER = 'search.ystg1.b.yahoo.com'

# I should be able to get this from the web server, but couldn't figure out how... equivalent to PHP's $_SERVER['REQUEST_URI']
REQUEST_PATH = '/search'

cgi = CGI.new

if (cgi['fr'] == 'aaplw') then

  # This search came from the Safari search box... redirect to preferred search engine
  
  query = cgi['p']
  
  print cgi.header(
    'status' => 'REDIRECT',
    'location' => sprintf(REPLACEMENT_URL, CGI::escape(query))
  )
  
else

  # Search didn't come from Safari. Redirect back to Yahoo.
  
  print cgi.header(
    'status' => 'REDIRECT',
    'location' => 'http://' + ALT_YAHOO_SERVER + REQUEST_PATH + '?' + cgi.query_string
  )

end