module Excon

def stub_for(request_params={})
  if method = request_params.delete(:method)
    request_params[:method] = method.to_s.downcase.to_sym
  end
  Excon.stubs.each do |stub, response_params|
    captures = { :headers => {} }
    headers_match = !stub.has_key?(:headers) || stub[:headers].keys.all? do |key|
      case value = stub[:headers][key]
      when Regexp
        if match = value.match(request_params[:headers][key])
          captures[:headers][key] = match.captures
        end
        match
      else
        value == request_params[:headers][key]
      end
    end
    non_headers_match = (stub.keys - [:headers]).all? do |key|
      case value = stub[key]
      when Regexp
        if match = value.match(request_params[key])
          captures[key] = match.captures
        end
        match
      else
        value == request_params[key]
      end
    end
    if headers_match && non_headers_match
      request_params[:captures] = captures
      return [stub, response_params]
    end
  end
  nil
end