Ruby on Rails

To integrate ProxyTracer into a Rails application with maximum efficiency, we bypass the controller layer entirely and build a custom Rack Middleware. This intercepts the raw HTTP request before it enters the Rails router.

The Rack Middleware

This middleware leverages the native Rack::Request object to safely extract the IP (handling spoofed headers automatically) and uses Ruby’s standard Net::HTTP library to enforce a strict timeout.


require 'net/http'
require 'json'
 
class ProxyTracerMiddleware
  def initialize(app)
    @app = app
    @api_key = ENV['PROXYTRACER_API_KEY']
  end
 
  def call(env)
    # 1. Extract the IP (Rack automatically sanitizes X-Forwarded-For)
    request = Rack::Request.new(env)
    ip = request.ip
 
    # Skip local development
    if ip && !['127.0.0.1', '::1'].include?(ip)
      begin
        uri = URI("https://api.proxytracer.com/v1/check/#{ip}")
        req = Net::HTTP::Get.new(uri)
        req['Authorization'] = "Bearer #{@api_key}"
 
        # 2. Query ProxyTracer API with a strict 500ms timeout
        response = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true, read_timeout: 0.5) do |http|
          http.request(req)
        end
 
        if response.is_a?(Net::HTTPSuccess)
          data = JSON.parse(response.body)
          
          # 3. Drop the connection immediately if a proxy is detected
          if data['proxy'] == true
            return [
              403,
              { 'Content-Type' => 'application/json' },
              ['{"error": "Access Denied: VPN or Proxy detected."}']
            ]
          end
        end
      rescue StandardError => e
        # Fail open: Log the error and allow the request to proceed
        Rails.logger.error("ProxyTracer validation failed: #{e.message}")
      end
    end
 
    # 4. Traffic is clean, proceed down the Rack stack to the Rails router
    @app.call(env)
  end
end

Configuration

To activate the protection globally, insert the middleware into your application stack inside config/application.rb:


module YourApp
  class Application < Rails::Application
    # ...
    
    # Insert it high up in the stack to reject bad traffic early
    config.middleware.insert_before Rack::Sendfile, ProxyTracerMiddleware
    
    # ...
  end
end