Refactor/hmac validator (#151) (#216)

* Replace doubles with singles for style

* Bring hmac validator test closer to real life

* Tidy-up hmac validator code

* Backwards compatibility aliasing

Co-authored-by: Matas Zanevičius <[email protected]>

Author: jillingk

lib/adyen/utils/hmac_validator.rb

@@ -15,7 +15,8 @@ def valid_notification_hmac?(notification_request_item, hmac_key)
 
       def valid_webhook_hmac?(webhook_request_item, hmac_key)
         expected_sign = calculate_webhook_hmac(webhook_request_item, hmac_key)
-        merchant_sign = fetch(webhook_request_item, 'additionalData.hmacSignature')
+        merchant_sign =
+          webhook_request_item.dig('additionalData', 'hmacSignature')
 
         expected_sign == merchant_sign
       end
@@ -29,29 +30,20 @@ def calculate_notification_hmac(notification_request_item, hmac_key)
       def calculate_webhook_hmac(webhook_request_item, hmac_key)
         data = data_to_sign(webhook_request_item)
 
-        Base64.strict_encode64(OpenSSL::HMAC.digest(HMAC_ALGORITHM, [hmac_key].pack('H*'), data))
+        Base64.strict_encode64(
+          OpenSSL::HMAC.digest(HMAC_ALGORITHM, [hmac_key].pack('H*'), data)
+        )
       end
 
+      # TODO: Deprecate instead of aliasing
+      alias valid_notification_hmac? valid_webhook_hmac?
+      alias calculate_notification_hmac calculate_webhook_hmac
 
       def data_to_sign(webhook_request_item)
-        data = WEBHOOK_VALIDATION_KEYS.map { |key| fetch(webhook_request_item, key).to_s }
-                                    .join(DATA_SEPARATOR)
-      end
-
-      private
-
-      def fetch(hash, keys)
-        value = hash
-        keys.to_s.split('.').each do |key|
-          value = if key.to_i.to_s == key
-                    value[key.to_i]
-                  else
-                    value[key].nil? ? value[key.to_sym] : value[key]
-                  end
-          break if value.nil?
-        end
-
-        value
+        WEBHOOK_VALIDATION_KEYS
+          .map { webhook_request_item.dig(*_1.split('.')).to_s }
+          .compact
+          .join(DATA_SEPARATOR)
       end
     end
   end

spec/utils/hmac_validator_spec.rb

@@ -6,19 +6,19 @@
   let(:expected_sign) { 'coqCmt/IZ4E3CzPvMY8zTjQVL5hYJUiBRg8UU+iCWo0=' }
   let(:webhook_request_item) do
     {
-      additionalData: {
-        hmacSignature: expected_sign
+      'additionalData' => {
+        'hmacSignature' => expected_sign
       },
-      amount: {
-        value: 1130,
-        currency: 'EUR'
+      'amount' => {
+        'value' => 1130,
+        'currency' => 'EUR'
       },
-      pspReference: '7914073381342284',
-      eventCode: 'AUTHORISATION',
-      merchantAccountCode: 'TestMerchant',
-      merchantReference: 'TestPayment-1407325143704',
-      paymentMethod: 'visa',
-      success: 'true'
+      'pspReference' => '7914073381342284',
+      'eventCode' => 'AUTHORISATION',
+      'merchantAccountCode' => 'TestMerchant',
+      'merchantReference' => 'TestPayment-1407325143704',
+      'paymentMethod' => 'visa',
+      'success' => 'true'
     }
   end
 
@@ -44,22 +44,22 @@
     end
 
     it 'should validate backslashes correctly' do
-      webhook = JSON.parse(json_from_file("mocks/responses/Webhooks/backslash_webhook.json"))
+      webhook = JSON.parse(json_from_file('mocks/responses/Webhooks/backslash_webhook.json'))
       expect(validator.valid_webhook_hmac?(webhook, '74F490DD33F7327BAECC88B2947C011FC02D014A473AAA33A8EC93E4DC069174')).to be true
     end
 
     it 'should validate colons correctly' do
-      webhook = JSON.parse(json_from_file("mocks/responses/Webhooks/colon_webhook.json"))
+      webhook = JSON.parse(json_from_file('mocks/responses/Webhooks/colon_webhook.json'))
       expect(validator.valid_webhook_hmac?(webhook, '74F490DD33F7327BAECC88B2947C011FC02D014A473AAA33A8EC93E4DC069174')).to be true
     end
 
     it 'should validate forward slashes correctly' do
-      webhook = JSON.parse(json_from_file("mocks/responses/Webhooks/forwardslash_webhook.json"))
+      webhook = JSON.parse(json_from_file('mocks/responses/Webhooks/forwardslash_webhook.json'))
       expect(validator.valid_webhook_hmac?(webhook, '74F490DD33F7327BAECC88B2947C011FC02D014A473AAA33A8EC93E4DC069174')).to be true
     end
 
     it 'should validate mix of slashes and colon correctly' do
-      webhook = JSON.parse(json_from_file("mocks/responses/Webhooks/mixed_webhook.json"))
+      webhook = JSON.parse(json_from_file('mocks/responses/Webhooks/mixed_webhook.json'))
       expect(validator.valid_webhook_hmac?(webhook, '74F490DD33F7327BAECC88B2947C011FC02D014A473AAA33A8EC93E4DC069174')).to be true
     end
   end