From 88ac6d8fc1d3dde20a8298731c487d09c5ca4012 Mon Sep 17 00:00:00 2001
From: Jonathan Lui <jonathanlui@google.com>
Date: Thu, 21 Jun 2018 12:48:53 -0700
Subject: [PATCH] more validation on credit card info; change smoke test for
 payment service to have a valid credit card

---
 src/paymentservice/charge.js         | 64 ++++++++++++++++++++++++++++
 src/paymentservice/package-lock.json |  5 +++
 src/paymentservice/package.json      |  3 +-
 src/paymentservice/server.js         | 16 +++----
 src/test-cli/main.go                 |  6 +--
 5 files changed, 80 insertions(+), 14 deletions(-)
 create mode 100644 src/paymentservice/charge.js

diff --git a/src/paymentservice/charge.js b/src/paymentservice/charge.js
new file mode 100644
index 0000000..2a16780
--- /dev/null
+++ b/src/paymentservice/charge.js
@@ -0,0 +1,64 @@
+const cardValidator = require('simple-card-validator');
+
+class CreditCardError extends Error {
+  constructor(message) {
+    super(message);
+    this.code = 400; // Invalid argument error
+  }
+}
+
+class InvalidCreditCard extends CreditCardError {
+  constructor(cardType) {
+    super(`Credit card info is invalid`);
+  }
+}
+
+class UnacceptedCreditCard extends CreditCardError {
+  constructor(cardType) {
+    super(`Sorry, we cannot process ${cardType} credit cards. Only VISA or MasterCard is accepted.`);
+  }
+}
+
+class ExpiredCreditCard extends CreditCardError {
+  constructor(number, month, year) {
+    super(`Your credit card (ending ${number.substr(-4)}) expired on ${month}/${year}`);
+  }
+}
+
+/**
+ * Verifies the credit card number and (pretend) charges the card.
+ *
+ * @param {*} request
+ * @return transaction_id - a random number.
+ */
+module.exports = function charge(request) {
+  const { amount, credit_card: creditCard } = request;
+  const cardNumber = creditCard.credit_card_number;
+  const cardInfo = cardValidator(cardNumber);
+  const {
+    card_type: cardType,
+    valid,
+    cvv_length: cvvLength,
+  } = cardInfo.getCardDetails();
+
+  if (!valid)
+    throw new InvalidCreditCard();
+
+  // Only VISA and mastercard is accepted, other card types (AMEX, dinersclub) will
+  // throw UnacceptedCreditCard error.
+  if (!(cardType === 'visa' || cardType == 'mastercard'))
+    throw new UnacceptedCreditCard(cardType);
+
+  // Also validate expiration is > today.
+  const currentMonth = new Date().getMonth() + 1;
+  const currentYear = new Date().getFullYear();
+  const { credit_card_expiration_year: year, credit_card_expiration_month: month } = creditCard;
+  if ((currentYear * 12 + currentMonth) > (year * 12 + month))
+    throw new ExpiredCreditCard(cardNumber.replace('-', ''), month, year);
+
+  console.log(`Transaction processed: ${cardType} ending ${cardNumber.substr(-4)} \
+    Amount: ${amount.currency_code}${amount.amount.decimal}.${amount.amount.fractional}`)
+
+  return { transaction_id: -1 }
+}
+
diff --git a/src/paymentservice/package-lock.json b/src/paymentservice/package-lock.json
index b037049..6393258 100644
--- a/src/paymentservice/package-lock.json
+++ b/src/paymentservice/package-lock.json
@@ -723,6 +723,11 @@
         "yargs": "3.32.0"
       }
     },
+    "simple-card-validator": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/simple-card-validator/-/simple-card-validator-1.1.0.tgz",
+      "integrity": "sha1-675uRp/q7Cy7SBX4Qyu+BMccNvk="
+    },
     "string-width": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/string-width/-/string-width-1.0.2.tgz",
diff --git a/src/paymentservice/package.json b/src/paymentservice/package.json
index 9c281d3..ee87b69 100644
--- a/src/paymentservice/package.json
+++ b/src/paymentservice/package.json
@@ -10,6 +10,7 @@
   "license": "ISC",
   "dependencies": {
     "@grpc/proto-loader": "^0.1.0",
-    "grpc": "^1.12.3"
+    "grpc": "^1.12.3",
+    "simple-card-validator": "^1.1.0"
   }
 }
diff --git a/src/paymentservice/server.js b/src/paymentservice/server.js
index 42eb6fb..1a3dc04 100644
--- a/src/paymentservice/server.js
+++ b/src/paymentservice/server.js
@@ -1,6 +1,8 @@
 const grpc = require('grpc');
 const protoLoader = require('@grpc/proto-loader');
 
+const charge = require('./charge');
+
 class HipsterShopServer {
   constructor(protoFile, port = HipsterShopServer.DEFAULT_PORT) {
     this.port = port;
@@ -16,24 +18,18 @@ class HipsterShopServer {
    */
   static ChargeServiceHandler(call, callback) {
     try {
-      const response = this.charge(call.request)
+      console.log(`PaymentService#Charge invoked with request ${JSON.stringify(call.request)}`)
+      const response = charge(call.request)
       callback(null, response);
     } catch (err) {
+      console.warn(err);
       callback(err);
     }
   }
 
-  /**
-   * Charge function
-   * @param {*} request
-   * @return transaction_id
-   */
-  static charge(request) {
-    return { transaction_id: -1 }
-  }
-
   listen() {
     this.server.bind(`0.0.0.0:${this.port}`, grpc.ServerCredentials.createInsecure());
+    console.log(`PaymentService grpc server listening on ${this.port}`);
     this.server.start();
   }
 
diff --git a/src/test-cli/main.go b/src/test-cli/main.go
index 13baf5a..1eeed2e 100644
--- a/src/test-cli/main.go
+++ b/src/test-cli/main.go
@@ -167,7 +167,7 @@ func testRecommendationService() error {
 }
 
 func testPaymentService() error {
-	addr := os.Getenv("RECOMMENDATION_SERVICE_ADDR")
+	addr := os.Getenv("PAYMENT_SERVICE_ADDR")
 	conn, err := grpc.Dial(addr, grpc.WithInsecure())
 	if err != nil {
 		return err
@@ -184,13 +184,13 @@ func testPaymentService() error {
 				Fractional: 55},
 		},
 		CreditCard: &pb.CreditCardInfo{
-			CreditCardNumber:          "9999-9999-9999-9999",
+			CreditCardNumber:          "4444-4530-1092-6639",
 			CreditCardCvv:             612,
 			CreditCardExpirationYear:  2022,
 			CreditCardExpirationMonth: 10},
 	})
 	if err != nil {
-		return nil
+		return err
 	}
 	log.Printf("--> resp: %+v", resp)
 	return nil