Coupon System

This ia a Functional Backend Stack Coupon System. This is targeting large-scale services. It is built using Java, PostgreSQL, and Spring Boot framework.

Development Stack

• Programming Language : Java 14
• Database : PostgreSQL
• Framework : Spring Boot 2.3.0
  • Gradle
  • JPA
  • Junit 5
• IDE : IntelliJ IDEA Ultimate
• OS : Windows
• Version Control : Git

Build and Execution

• Terminal Environment

   $ ./gradlew clean build
   $ java -jar kakao-0.0.1-SNAPSHOT.jar
   

• Access URI

http://localhost:5000

• Swagger

http://localhost:5000/swagger-ui.html

API List

1. Coupon Generation API

  URL : /api/coupon/createCoupon
  Method : POST

• Header

Token	Authentication Authority
Bearer	ADMIN

2. Coupon Payment API

  URL : /api/coupon/payCoupon
  Method : POST

• Header

Token	Authentication Authority
Bearer	ADMIN,USER

• Parameter

Value	Type	Required
email	String	Y

3. Coupon Retrieval API

  URL : /api/coupon/viewCoupon
  Method : GET

• Header

Token	Authentication Authority
Bearer	ADMIN,USER

• Parameter

Value	Type	Required
email	String	Y

4. Coupon Utilization API

  URL : /api/coupon/useCoupon/{couponId}/{utilizationStatus}
  Method : GET

• Header

Token	Authentication Authority
Bearer	USER

• Parameter

Value	Type	Required
email	String	Y
couponId	Long	Y

5. Coupon Cancellation API

  URL : /api/coupon/useCoupon/{couponId}/{utilizationStatus}
  Method : GET

• Header

Token	Authentication Authority
Bearer	USER

• Parameter

Value	Type	Required
email	String	Y
couponId	Long	Y

6. Expiration Coupons Retrieval API

  URL : /api/coupon/viewExpirationCoupons
  Method : GET

• Header

Token	Authentication Authority
Bearer	ADMIN

7. User Registration API

• Spring Security
• a token-based api authentication function using jwt

 URL : /api/user/signup
 Method : POST

• Parameter

Value	Type	Required
email	String	Y
name	String	Y
password	String	Y

8. User Login API

  URL : /api/user/signin
  Method : POST

• Parameter

Value	Type	Required
email	String	Y
password	String	Y

+ Message Sending function before 3 days expiration of issued Coupon

 
   * getAllCouponsByExpirationDate() : the scheduler to check coupons 3 days before expiration at 9:30 AM 
   * (confirmMessageStoredStatus()) : To prevent duplicate storage, check whether the data is present in the coupon message table , Save it to the table only if data doesn't exist.
   * message confirmation column -> default: false
   * changeCouponMessageCheckStatus() : When the user accesses and checks the message, the message confirmation column changes to true.
   

Problem Solving

1. Coupon Code Generation Method

1-1. Random String generation (Example : dmxcdyf8zo0t13t1ahya)

• Coupon Code stored with Hash value can be fast search
  • Random code generation mixing 20 digits of English and numbers
  • Use java.util.Random class
  • nextBoolean() method return true(lower case),false(random numbers)
  • nextInt() method convertor returned numbers to 62 digit([0-9][a-z][A-Z])
  • Random String generation of a 20 digits arbitrary string connecting all characters created by repeating 20 times with StringBuffer

1-2. HashCode Generation (Example : 1828977362)

• Get the generated random code, create a Hash Code, and save it together

  • Use java.util.zip.CRC32
  • Change the random code to byte array
  • Create a CRC32 Long-form code using the byte array value update() function

• Realistic performance issues

  • From a small number of data, random code can be inquired and generated.
  • However, when searching hundreds of millions of data, it costs a lot to check the code value.
  • Inquiry by storing hash code values created when issuing coupon codes (reduced from 40 seconds to 20 seconds when 9,991 pieces are stored at once).