A Reverse Proxy for Rack¶ ↑

This is a simple reverse proxy for Rack that pretty heavily rips off Rack Forwarder. It is not meant for production systems (although it may work), as the webserver fronting your app is generally much better at this sort of thing.

Installation¶ ↑

The gem is available on gemcutter. Assuming you have a recent version of Rubygems you should just be able to install it via:

gem install rack-reverse-proxy

For your Gemfile use:

gem "rack-reverse-proxy", :require => "rack/reverse_proxy"

Usage¶ ↑

Matchers can be a regex or a string. If a regex is used, you can use the subcaptures in your forwarding url by denoting them with a $.

Right now if more than one matcher matches any given route, it throws an exception for an ambiguous match. This will probably change later. If no match is found, the call is forwarded to your application.

Below is an example for configuring the middleware:

require 'rack/reverse_proxy'

use Rack::ReverseProxy do 
  # Set :preserve_host to true globally (default is true already)
  reverse_proxy_options :preserve_host => true

  # Keep additional headers other than the HTTP_* headers from the original request.
  keep_headers ["X-AUTH","HEADER1"]

  #Add additional headers to the proxy request 
  extra_headers {"X_AUTH" =>"super secret", "HTTP_AUTHROIZATION" => lambda{|env| env["rack.session"]["auth_param"]}}
  #Supports adding static headers and dynamic headers via lambda.  This could also be a lambda that returns a Hash of headers

  # Forward the path /test* to http://example.com/test*
  reverse_proxy '/test', 'http://example.com/'

  # Forward the path /foo/* to http://example.com/bar/*
  reverse_proxy /^\/foo(\/.*)$/, 'http://example.com/bar$1', :username => 'name', :password => 'basic_auth_secret'

  #Forward the path /test2* to http://example.com/test* with extra header information for only this matcher
  reverse_proxy '/test2', 'http://example.com/', :extra_headers=>{"X_HEADER" => "header value", "X_HEADER_2" => "Header val 2"}
  #same semantics apply for the per matcher headers as for the global headers, static , a proc in the hash, or just a proc that returns a hash

end

app = proc do |env|
  [ 200, {'Content-Type' => 'text/plain'}, "b" ]
end
run app

reverse_proxy_options sets global options for all reverse proxies. Available options are:

• :preserve_host Set to false to omit Host headers

• :username username for basic auth

• :password password for basic auth

• :matching is a global only option, if set to :first the first matched url will be requested (no ambigous error). Default: :all.

• :timeout seconds to timout the requests

To set them at a global level simply declare them

Note on Patches/Pull Requests¶ ↑

• Fork the project.

• Make your feature addition or bug fix.

• Add tests for it. This is important so I don’t break it in a future version unintentionally.

• Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)

• Send me a pull request. Bonus points for topic branches.

Copyright¶ ↑

Copyright © 2010 Jon Swope. See LICENSE for details.