hanami_path_resolver.rb

module Cs
  module Hanami
    class PathResolver
      def self.call(env)
        new.call(env)
      end

      def call(env)
        path = env['REQUEST_URI'].split('?').first # path without query string
        return 'root' if path == '/'

        configs = ::Hanami.configuration.mounted.values
        app = configs.find { |config| path.start_with?(config.path_prefix) }

        if app
          # returns Api, Web, ...
          app_constant = Module.const_get(app.to_s.split('::').first)

          relative_path = path.split(app.path_prefix, 2).last

          env_with_path = env.merge('PATH_INFO' => relative_path)

          # returns either nil or something of the form "web_controllers/alive#index"
          app_constant.routes.recognize(env_with_path).action
        end
      end
    end
  end
end

hanami_path_resolver_spec.rb

RSpec.describe Cs::Hanami::PathResolver do
  subject { described_class.call(env) }

  let(:env) do
    verb, path = self.class.description.split
    { 'REQUEST_METHOD' => verb, 'REQUEST_URI' => path }
  end

  context 'GET /surveyors' do
    it { is_expected.to eq('web_controllers/surveyors#index') }
  end

  context 'GET /surveyors.js' do
    it { is_expected.to eq('web_controllers/surveyors#index') }
  end

  context 'GET /claims/new' do
    it { is_expected.to eq('web_controllers/claims#new') }
  end

  context 'GET /claims/new?group=fruit' do
    it { is_expected.to eq('web_controllers/claims#new') }
  end

  context 'GET /alive' do
    it { is_expected.to eq('web_controllers/alive#index') }
  end

  context 'GET /go' do
    it { is_expected.to eq('web_controllers/home#index') }
  end

  context 'PATCH /locales/42' do
    it { is_expected.to eq('web_controllers/locales#update') }
  end

  context 'GET /' do
    it { is_expected.to eq('root') }
  end
end