Create AuthTokenCreator and AuthTokenDecryptor classes

lib/auth_token/auth_token_creator.rb

@@ -0,0 +1,41 @@
+class AuthTokenCreator
+  DEFAULT_VALIDITY = 2.hours
+
+  attr_reader :user
+  attr_reader :key
+  attr_reader :expires_at
+
+  def self.create_with_defaults(user)
+    self.new(user, Rails.application.config.secret_key_base, Time.now + DEFAULT_VALIDITY)
+  end
+
+  def initialize(user, key, expires_at)
+    @user = user
+    @key = key
+    @expires_at = expires_at.utc.strftime("%F %T %Z")
+  end
+
+  def hashable
+    {
+      user_ident: user.registrant_ident,
+      user_username: user.username,
+      expires_at: expires_at
+    }.to_json
+  end
+
+  def encrypted_token
+    encryptor = OpenSSL::Cipher::AES.new(256, :CBC)
+    encryptor.encrypt
+    encryptor.key = key
+    encrypted_bytes = encryptor.update(hashable) + encryptor.final
+    Base64.encode64(encrypted_bytes)
+  end
+
+  def token_in_hash
+    {
+      access_token: encrypted_token,
+      expires_at: expires_at,
+      type: 'Bearer'
+    }
+  end
+end