Feature | Authenticator with cache

Gemfile

@@ -14,3 +14,7 @@ gem "rubocop", "~> 1.21"
 group :development do
   gem "dotenv"
 end
+
+group :test do
+  gem "webmock"
+end

Gemfile.lock

@@ -8,7 +8,13 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
+    addressable (2.8.7)
+      public_suffix (>= 2.0.2, < 7.0)
     ast (2.4.2)
+    bigdecimal (3.1.9)
+    crack (1.0.0)
+      bigdecimal
+      rexml
     dotenv (3.1.7)
     faraday (1.10.4)
       faraday-em_http (~> 1.0)
@@ -35,6 +41,7 @@ GEM
     faraday-retry (1.0.3)
     faraday_middleware (1.2.1)
       faraday (~> 1.0)
+    hashdiff (1.1.2)
     json (2.9.1)
     language_server-protocol (3.17.0.4)
     minitest (5.25.4)
@@ -43,10 +50,12 @@ GEM
     parser (3.3.7.0)
       ast (~> 2.4.1)
       racc
+    public_suffix (6.0.1)
     racc (1.8.1)
     rainbow (3.1.1)
     rake (13.2.1)
     regexp_parser (2.10.0)
+    rexml (3.4.0)
     rubocop (1.71.0)
       json (~> 2.3)
       language_server-protocol (>= 3.17.0)
@@ -64,6 +73,10 @@ GEM
     unicode-display_width (3.1.4)
       unicode-emoji (~> 4.0, >= 4.0.4)
     unicode-emoji (4.0.4)
+    webmock (3.25.0)
+      addressable (>= 2.8.0)
+      crack (>= 0.3.2)
+      hashdiff (>= 0.4.0, < 2.0.0)
 
 PLATFORMS
   ruby
@@ -75,6 +88,7 @@ DEPENDENCIES
   rake (~> 13.0)
   ruber!
   rubocop (~> 1.21)
+  webmock
 
 BUNDLED WITH
    2.5.22

README.md

@@ -19,6 +19,17 @@ If bundler is not being used to manage dependencies, install the gem by executin
 ```bash
 gem install UPDATE_WITH_YOUR_GEM_NAME_IMMEDIATELY_AFTER_RELEASE_TO_RUBYGEMS_ORG
 ```
+## Cache
+Ruber uses a caching solution to improve efficiency (e.g., for caching tokens). By default, it uses a simple in-memory cache, but you can change the cache method by setting the `Ruber.cache` attribute
+
+
+```ruby
+Ruber.cache = Redis.new
+# or
+Ruber.cache = Rails.cache
+# or any object that responds to read/write/delete/clear
+Ruber.cache = YourCustomCache.new
+```
 
 ## Usage
 

lib/ruber.rb

@@ -3,11 +3,13 @@
 require_relative "ruber/version"
 require "forwardable"
 require "ruber/configuration"
+require "ruber/authenticator"
 
 # a Ruby wrapper for Uber API
 module Ruber
   autoload :Client, "ruber/client"
   autoload :Error, "ruber/error"
+  autoload :Authenticator, "ruber/authenticator"
 
   DEFAULT_API_BASE = "https://api.uber.com/v1"
 
@@ -16,7 +18,7 @@ class << self
 
     def_delegators(
       :configuration, :customer_id, :client_id, :client_secret,
-      :customer_id=, :client_id=, :client_secret=
+      :customer_id=, :client_id=, :client_secret=, :cache, :cache=
     )
   end
 end

lib/ruber/authenticator.rb

@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require "faraday"
+require "json"
+
+module Ruber
+  class Authenticator
+    OAUTH_URL = "https://auth.uber.com/oauth/v2/token"
+    GRANT_TYPE = "client_credentials"
+    SCOPE = "eats.deliveries"
+
+    class << self
+      def access_token
+        @access_token = cached_token || fetch_new_token
+
+        @access_token = refresh_access_token if token_expired?
+
+        @access_token
+      end
+
+      def refresh_access_token
+        Ruber.cache.delete(cache_key)
+
+        fetch_new_token
+      end
+
+      def cache_key
+        @cache_key ||= "#{Ruber.customer_id}_#{Ruber.client_id}_access_token"
+      end
+
+      private
+
+      def token_expired?
+        cached_token[:expires_at] < Time.now
+      end
+
+      def cached_token
+        Ruber.cache.read(cache_key)
+      end
+
+      def fetch_new_token
+        response = Faraday.post(
+          OAUTH_URL,
+          {
+            client_id: Ruber.client_id,
+            client_secret: Ruber.client_secret,
+            grant_type: GRANT_TYPE,
+            scope: SCOPE
+          }
+        )
+
+        data = JSON.parse(response.body.to_s)
+
+        expires_at = Time.now + data["expires_in"].to_i
+        Ruber.cache.write(cache_key, { token: data["access_token"], expires_at: expires_at })
+
+        data["access_token"]
+      end
+    end
+  end
+end

lib/ruber/cache.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module Ruber
+  class NullCache
+    def read(key) = memory_store[key]
+    def write(key, value, _options = {}) = memory_store[key] = value
+    def clear = memory_store.clear
+    def delete(key) = memory_store.delete(key)
+    def memory_store = @memory_store ||= {}
+  end
+
+  class << self
+    def cache=(store)
+      unless %i[read write clear delete].all? { |method| store.respond_to?(method) }
+        raise ArgumentError, "cache_store must respond to read, write, clear, and delete"
+      end
+
+      @cache = store
+    end
+
+    def cache
+      @cache ||= NullCache.new
+    end
+  end
+end

lib/ruber/configuration.rb

@@ -1,18 +1,36 @@
 # frozen_string_literal: true
 
+require_relative "configuration/null_cache"
+
 module Ruber
   class Configuration
     attr_accessor :customer_id, :client_id, :client_secret
+
+    def cache
+      @cache ||= NullCache.new
+    end
+
+    def cache=(store)
+      unless %i[read write clear delete].all? { |method| store.respond_to?(method) }
+        raise ArgumentError, "cache_store must respond to read, write, clear, and delete"
+      end
+
+      @cache = store
+    end
   end
 
   class << self
     def configuration
       @configuration ||= Configuration.new
     end
 
-    def configuration=(config_hash)
-      config_hash.each do |key, value|
-        configuration.send "#{key}=", value
+    def configuration=(config)
+      if config.is_a?(Hash)
+        config.each do |key, value|
+          configuration.send "#{key}=", value
+        end
+      else
+        @configuration = config
       end
 
       configuration

lib/ruber/configuration/null_cache.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module Ruber
+  class Configuration
+    class NullCache
+      def read(key) = memory_store[key]
+      def write(key, value, _options = {}) = memory_store[key] = value
+      def clear = memory_store.clear
+      def delete(key) = memory_store.delete(key)
+      def memory_store = @memory_store ||= {}
+    end
+  end
+end

test/ruber/authenticator_test.rb

@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "webmock/minitest"
+
+module Ruber
+  class AuthenticatorTest < Minitest::Test
+    include WebMock::API
+
+    def setup
+      Ruber.cache.clear
+    end
+
+    def test_access_token_fetches_and_caches_token
+      stub_token_request(access_token: "new_token", expires_in: 3600)
+
+      token = Authenticator.access_token
+      cached_token = Ruber.cache.read(Authenticator.cache_key)
+
+      assert_equal "new_token", token
+      assert_equal "new_token", cached_token[:token]
+    end
+
+    def test_refresh_access_token_forces_new_token
+      Ruber.cache.write(Authenticator.cache_key, { token: "old_token", expires_at: Time.now + 3600 })
+
+      stub_token_request(access_token: "refreshed_token", expires_in: 3600)
+
+      token = Authenticator.refresh_access_token
+      cached_token = Ruber.cache.read(Authenticator.cache_key)
+
+      assert_equal "refreshed_token", token
+      assert_equal "refreshed_token", cached_token[:token]
+    end
+
+    def test_refresh_access_token_if_expired
+      Ruber.cache.write(Authenticator.cache_key, { token: "expired_token", expires_at: Time.now - 3600 })
+
+      stub_token_request(access_token: "refreshed_token", expires_in: 3600)
+
+      token = Authenticator.access_token
+      cached_token = Ruber.cache.read(Authenticator.cache_key)
+
+      assert_equal "refreshed_token", token
+      assert_equal "refreshed_token", cached_token[:token]
+    end
+
+    private
+
+    def stub_token_request(access_token:, expires_in:)
+      stub_request(:post, Authenticator::OAUTH_URL)
+        .to_return(
+          status: 200,
+          body: {
+            access_token: access_token,
+            expires_in: expires_in
+          }.to_json
+        )
+    end
+  end
+end

test/ruber/configuration_test.rb

@@ -5,23 +5,37 @@
 module Ruber
   class ConfigurationTest < Minitest::Test
     def setup
-      @config_values = { customer_id: "1111", client_id: "2222", client_secret: "a-secret" }
+      @config_values = {
+        customer_id: "1111",
+        client_id: "2222",
+        client_secret: "a-secret"
+      }
+
+      @custom_cache = Class.new do
+        def read(key) = memory_store[key]
+        def write(key, value, _options = {}) = memory_store[key] = value
+        def clear = memory_store.clear
+        def delete(key) = memory_store.delete(key)
+        def memory_store = @memory_store ||= {}
+      end.new
+
+      Ruber.configuration = nil
     end
 
     def test_configure
       Ruber.configure do |config|
-        config.customer_id = @config_values[:customer_id]
-        config.client_id = @config_values[:client_id]
-        config.client_secret = @config_values[:client_secret]
+        config.customer_id    = @config_values[:customer_id]
+        config.client_id      = @config_values[:client_id]
+        config.client_secret  = @config_values[:client_secret]
       end
 
       assert_configuration_values
     end
 
     def test_direct_configuration
-      Ruber.customer_id = @config_values[:customer_id]
-      Ruber.client_id = @config_values[:client_id]
-      Ruber.client_secret = @config_values[:client_secret]
+      Ruber.customer_id       = @config_values[:customer_id]
+      Ruber.client_id         = @config_values[:client_id]
+      Ruber.client_secret     = @config_values[:client_secret]
 
       assert_configuration_values
     end
@@ -38,6 +52,18 @@ def test_invalid_configuration_set
       end
     end
 
+    def test_cache_can_be_set_explicitly
+      Ruber.cache = @custom_cache
+
+      assert_equal @custom_cache, Ruber.cache
+    end
+
+    def test_cache_must_respond_to_read_write_clear_and_delete
+      assert_raises(ArgumentError) do
+        Ruber.cache = Object.new
+      end
+    end
+
     private
 
     def assert_configuration_values

test/test_helper.rb

@@ -4,3 +4,4 @@
 require "ruber"
 
 require "minitest/autorun"
+require "webmock/minitest"