Refactor JWT token verification and decoding

app/controllers/crazy_train/application_controller.rb

@@ -12,14 +12,23 @@ class ApplicationController < ActionController::Base
 
     def verify_token
       @default_role = current_role
-      @role = if jwt_token && jwt_payload
-                jwt_payload['role'] || CrazyTrain.config.authenticated_role
-              else
-                CrazyTrain.config.unauthorized_role
-              end
-
-      payload_string = JSON.generate(jwt_payload)
-      CrazyTrain.setup_jwt_claims!(payload_string)
+
+      if bearer.nil?
+        @role = CrazyTrain.config.unauthorized_role
+        return
+      end
+
+      jwt = CrazyTrain::JWT.new(bearer)
+      jwt.decode!
+
+      @role =
+        if jwt.valid?
+          jwt.role || CrazyTrain.config.authenticated_role
+        else
+          CrazyTrain.config.unauthorized_role
+        end
+
+      CrazyTrain.setup_jwt_claims!(jwt.payload_string)
     end
 
     def setup_role
@@ -30,16 +39,10 @@ def teardown_role
       switch_role(@default_role)
     end
 
-    def jwt_token
-      request.headers['Authorization'].split.last
-    rescue StandardError
-      nil
-    end
+    private
 
-    def jwt_payload
-      CrazyTrain::JWT.decode(jwt_token, CrazyTrain.config.secret).first
-    rescue StandardError
-      nil
+    def bearer
+      request.headers['Authorization']&.sub(/^Bearer: /, '')
     end
   end
 end

lib/crazy_train/jwt.rb

@@ -2,23 +2,57 @@
 
 module CrazyTrain
   class JWT
-    HEADERS = { 'alg' => 'HS256', 'typ' => 'JWT' }.freeze
+    class << self
+      HEADERS = { 'alg' => 'HS256', 'typ' => 'JWT' }.freeze
 
-    def self.encode(payload, secret = CrazyTrain.config.secret)
-      ::JWT.encode(payload, secret, 'HS256', HEADERS)
+      def encode(payload, secret = CrazyTrain.config.secret)
+        ::JWT.encode(payload, secret, 'HS256', HEADERS)
+      end
+
+      def decode(token, secret = CrazyTrain.config.secret)
+        ::JWT.decode(token, secret, true, HEADERS)
+      end
+
+      def generate_jwt_secret
+        SecureRandom.alphanumeric(32)
+      end
+    end
+
+    attr_reader :raw_token,
+                :secret,
+                :raw_header,
+                :raw_payload,
+                :raw_signeture,
+                :header,
+                :payload,
+                :signeture
+
+    def initialize(raw_token, secret = CrazyTrain.config.secret)
+      @raw_token = raw_token
+      @secret = secret
+      @header = nil
+      @payload = nil
+      @signeture = nil
+
+      @raw_header, @raw_payload, @raw_signeture = @raw_token.split('.') if raw_token
+    end
+
+    def parse!; end
+
+    def decode!
+      @payload, @header = CrazyTrain::JWT.decode(@raw_token, @secret)
     end
 
-    def self.decode(token, secret = CrazyTrain.config.secret)
-      ::JWT.decode(token, secret, true, HEADERS)
+    def role
+      payload.fetch('role', nil)
     end
 
-    def self.generate_token(payload_string)
-      payload = JSON.parse(payload_string || '{}')
-      encode(payload)
+    def valid?
+      @header && @payload
     end
 
-    def self.generate_jwt_secret
-      SecureRandom.alphanumeric(32)
+    def payload_string
+      JSON.generate(@payload)
     end
   end
 end

lib/tasks/crazy_train.rake

@@ -2,6 +2,7 @@ require 'crazy_train'
 
 namespace :crazy_train do
   task generate_token: :environment do
-    puts CrazyTrain::JWT.generate_token(ENV.fetch('PAYLOAD', nil))
+    payload = ENV.fetch('PAYLOAD', nil)
+    puts CrazyTrain::JWT.encode(payload)
   end
 end

test/crazy_train/jwt_test.rb

@@ -3,10 +3,10 @@
 module CrazyTrain
   class JWTTest < ActiveSupport::TestCase
     setup do
-      @payload = { 'iss' => 'crazy_train' }.freeze
       @headers = { 'alg' => 'HS256', 'typ' => 'JWT' }.freeze
-      @secret = 'a' * 32
-      @token = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJjcmF6eV90cmFpbiJ9.tUAwhK5t_UOqDLubyZg1fEt4Vl-w4pyur6vrdSjqiBI'
+      @payload = { 'iss' => 'crazy_train' }.freeze
+      @secret = '0123456789'
+      @token = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJjcmF6eV90cmFpbiJ9.a-9Uf4KIyYpOIGODLc5pXP2bY3DHQ-lNtmE-RK8sWgo'
     end
 
     test '.encode' do
@@ -21,5 +21,12 @@ class JWTTest < ActiveSupport::TestCase
       assert_equal @payload, payload
       assert_equal @headers, headers
     end
+
+    test '.decode!' do
+      jwt = ::CrazyTrain::JWT.new(@token, @secret)
+      jwt.decode!
+
+      assert_equal @payload, jwt.payload
+    end
   end
 end