Roda::Proxy

Roda Proxy is a very simple reverse proxy for Roda. It is designed to proxy APIs, it will not rewrite HTML.

Installation

Add this line to your application's Gemfile:

gem 'roda-proxy'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install roda-proxy

Usage

Add the plugin to your Roda app and pass it two parameters (one is required, one is optional).

require 'roda'
require 'roda/proxy'

class App < Roda
  plugin :proxy, 
         to: 'https://my.server.com', 
         path_prefix: '/my/api/path'

The to: parameter is required. It should describe the scheme, host and port of the proxy. It should not end with a /.

The path_prefix: parameter is optional. It defaults to /. If you chose to specify it, it should start and end with a /.

The plugin provides both an unconditional and a conditional proxy directive.

To invoke the proxy in your routes, see this example:

route do |r|
  # /my
  r.on 'my' do
    # /my/api
    r.on 'api' do
      # /my/api/path
      r.is 'path' do
        # GET /my/api/path
        r.get do
          r.proxy
        end
      end
    end
  end
end

The proxy will always be invoked. Headers and body are passed through unmodified in both directions with the exception of Host which is rewritten to match the target and Via which is created (or appended to if it already exists) to indicate the proxy path.

Also provided is a conditional proxy:

route do |r|
  # /my
  r.on 'my' do
    # /my/api
    r.on 'api' do
      # /my/api/path
      r.is 'path' do
        # GET /my/api/path
        r.get do
          r.proxy_when(r.env['HTTP_PROXY'] == 'true', probability: 0.5) do
            'This request has not been proxied'
          end
        end
      end
    end
  end
end

With proxy_when the first optional parameter expects a truthy value or a block / lambda that returns a truthy value. This must be equivalent to true for the proxying to occur. The optional probability is a float between 0 and 1 indicating the probability that proxying will happen. Both paramters can be used alone or in isolation.

If and only if proxying does not occur will the block be evaluated and return to Roda for rendering.

License

The gem is available as open source under the terms of the MIT License.