Claims Validation

lib/jwt/claims_validator.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require_relative './error'
+
+module JWT
+  class ClaimsValidator
+    def initialize(payload)
+      @payload = payload.each_with_object({}) { |(k, v), h| h[k.to_sym] = v }
+    end
+
+    def validate
+      validate_exp if @payload[:exp]
+
+      true
+    end
+
+    private
+
+    def validate_exp
+      raise InvalidPayload, 'exp claim must be an integer' unless @payload[:exp].is_a?(Integer)
+    end
+  end
+end

spec/jwt/claims_validator_spec.rb

@@ -0,0 +1,31 @@
+require 'spec_helper'
+require 'jwt/claims_validator'
+
+RSpec.describe JWT::ClaimsValidator do
+  describe '#validate' do
+    it 'returns true if the payload is valid' do
+      valid_payload = { 'exp' => 12345 }
+      subject = described_class.new(valid_payload)
+
+      expect(subject.validate).to eq(true)
+    end
+
+    it 'raises an error when the value of the exp claim is a string' do
+      subject = described_class.new({ exp: '1' })
+      expect { subject.validate }.to raise_error JWT::InvalidPayload
+    end
+
+    it 'raises an error when the value of the exp claim is a Time object' do
+      subject = described_class.new({ exp: Time.now })
+      expect { subject.validate }.to raise_error JWT::InvalidPayload
+    end
+
+    it 'validates the exp when the exp key is either a string or a symbol' do
+      symbol = described_class.new({ exp: true })
+      expect { symbol.validate }.to raise_error JWT::InvalidPayload
+
+      string = described_class.new({ 'exp' => true })
+      expect { string.validate }.to raise_error JWT::InvalidPayload
+    end
+  end
+end