Generate nonce from public hash server-side

This simplifies the implementation requirements when setting the payment
method to Braintree Vault.

In the current frontend implementation the nonce is created server-side, but
using an ajax request when the place order button is activated. The current
storefront flow executes:
1. User selects vault method and places order
2. Ajax request with public hash is made to server returning the nonce
3. Nonce is submitted with order placement request in payment details

The second step is uncessecary and is removed from the graphql flow with this
commit.

Author: pmclain

app/code/Magento/BraintreeGraphQl/Plugin/SetVaultPaymentNonce.php

@@ -0,0 +1,76 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\BraintreeGraphQl\Plugin;
+
+use Magento\Braintree\Gateway\Command\GetPaymentNonceCommand;
+use Magento\Braintree\Model\Ui\ConfigProvider;
+use Magento\Framework\GraphQl\Exception\GraphQlInputException;
+use Psr\Log\LoggerInterface;
+
+/**
+ * Plugin creating nonce from Magento Vault Braintree public hash
+ */
+class SetVaultPaymentNonce
+{
+    /**
+     * @var GetPaymentNonceCommand
+     */
+    private $command;
+
+    /**
+     * @var LoggerInterface
+     */
+    private $logger;
+
+    /**
+     * @param GetPaymentNonceCommand $command
+     * @param LoggerInterface $logger
+     */
+    public function __construct(
+        GetPaymentNonceCommand $command,
+        LoggerInterface $logger
+    ) {
+        $this->command = $command;
+        $this->logger = $logger;
+    }
+
+    /**
+     * Set Braintree nonce from public hash
+     *
+     * @param \Magento\QuoteGraphQl\Model\Cart\SetPaymentMethodOnCart $subject
+     * @param \Magento\Quote\Model\Quote $quote
+     * @param array $paymentData
+     * @return array
+     * @SuppressWarnings(PHPMD.UnusedFormalParameter)
+     */
+    public function beforeExecute(
+        \Magento\QuoteGraphQl\Model\Cart\SetPaymentMethodOnCart $subject,
+        \Magento\Quote\Model\Quote $quote,
+        array $paymentData
+    ): array {
+        if ($paymentData['code'] !== ConfigProvider::CC_VAULT_CODE) {
+            return [$quote, $paymentData];
+        }
+
+        $subject = [
+            'public_hash' => $paymentData[ConfigProvider::CC_VAULT_CODE]['public_hash'],
+            'customer_id' => $quote->getCustomerId(),
+            'store_id' => $quote->getStoreId(),
+        ];
+
+        try {
+            $result = $this->command->execute($subject)->get();
+            $paymentData[ConfigProvider::CC_VAULT_CODE]['payment_method_nonce'] = $result['paymentMethodNonce'];
+        } catch (\Exception $e) {
+            $this->logger->critical($e);
+            throw new GraphQlInputException(__('Sorry, but something went wrong'));
+        }
+
+        return [$quote, $paymentData];
+    }
+}

app/code/Magento/BraintreeGraphQl/composer.json

@@ -5,6 +5,9 @@
     "require": {
         "php": "~7.1.3||~7.2.0",
         "magento/framework": "*",
+        "magento/module-braintree": "*",
+        "magento/module-store": "*",
+        "magento/module-quote": "*",
         "magento/module-quote-graph-ql": "*"
     },
     "suggest": {

app/code/Magento/BraintreeGraphQl/etc/graphql/di.xml

@@ -14,4 +14,7 @@
             </argument>
         </arguments>
     </type>
+    <type name="Magento\QuoteGraphQl\Model\Cart\SetPaymentMethodOnCart">
+        <plugin name="braintree_generate_vault_nonce" type="Magento\BraintreeGraphQl\Plugin\SetVaultPaymentNonce" />
+    </type>
 </config>

app/code/Magento/BraintreeGraphQl/etc/schema.graphqls

@@ -17,8 +17,6 @@ input BraintreeInput {
 }
 
 input BraintreeCcVaultInput {
-    payment_method_nonce: String!
     public_hash: String!
-    is_active_payment_token_enabler: Boolean!
     device_data: String
 }

dev/tests/api-functional/_files/Magento/TestModuleBraintree/Model/Adapter/BraintreeAdapter.php

@@ -66,6 +66,7 @@ public function sale(array $attributes)
     /**
      * @param array $params
      * @return string|\Braintree\Result\Error
+     * @SuppressWarnings(PHPMD.UnusedFormalParameter)
      */
     public function generate(array $params = [])
     {

dev/tests/api-functional/_files/Magento/TestModuleBraintree/Model/MockResponseDataProvider.php

@@ -32,10 +32,26 @@ public function __construct(
      * Create mock sale response for testing
      *
      * @param array $attributes
-     * @return \Braintree\Instance
+     * @return \Braintree\Result\Error|\Braintree\Result\Successful
      */
-    public function generateMockSaleResponse(array $attributes): \Braintree\Instance
+    public function generateMockSaleResponse(array $attributes)
     {
+        if (empty($attributes['paymentMethodNonce'])) {
+            return new \Braintree\Result\Error(
+                [
+                    'errors' => [
+                        [
+                            'errorData' => [
+                                'code' => 2019,
+                                'message' => 'Your transaction has been declined.'
+                            ]
+                        ]
+                    ],
+                    'transaction' => $this->createTransaction($attributes)->jsonSerialize(),
+                ]
+            );
+        }
+
         $transaction = $this->createTransaction($attributes);
 
         return new \Braintree\Result\Successful([$transaction]);

dev/tests/api-functional/testsuite/Magento/GraphQl/Braintree/Customer/SetPaymentMethodTest.php

@@ -169,19 +169,9 @@ public function testPlaceOrderWithVault()
         $reservedOrderId = 'test_quote';
         $maskedQuoteId = $this->getMaskedQuoteIdByReservedOrderId->execute($reservedOrderId);
 
-        $nonceResult = $this->getNonceCommand->execute(
-            [
-                'customer_id' => 1,
-                'public_hash' => 'braintree_public_hash',
-            ]
-        );
-        $nonce = $nonceResult->get()['paymentMethodNonce'];
-
         $setPaymentQuery = $this->getSetPaymentBraintreeVaultQuery(
             $maskedQuoteId,
-            'braintree_public_hash',
-            $nonce,
-            true
+            'braintree_public_hash'
         );
         $setPaymentResponse = $this->graphQlMutation($setPaymentQuery, [], '', $this->getHeaderMap());
 
@@ -243,26 +233,19 @@ private function getSetPaymentBraintreeQuery(string $maskedQuoteId, bool $saveIn
     /**
      * @param string $maskedQuoteId
      * @param string $publicHash
-     * @param string $nonce
-     * @param bool $saveInVault
      * @return string
      */
     private function getSetPaymentBraintreeVaultQuery(
         string $maskedQuoteId,
-        string $publicHash,
-        string $nonce,
-        bool $saveInVault = false
+        string $publicHash
     ): string {
-        $saveInVault = json_encode($saveInVault);
         return <<<QUERY
 mutation {
   setPaymentMethodOnCart(input:{
     cart_id:"{$maskedQuoteId}"
     payment_method:{
       code:"braintree_cc_vault"
       braintree_cc_vault:{
-        is_active_payment_token_enabler:{$saveInVault}
-        payment_method_nonce:"{$nonce}"
         public_hash:"{$publicHash}"
       }
     }