How are purchases validated?

Question

go

There is a repository https://github.com/panuwattoa/in-app-purchase/

There is a func NewValidate() function in the validate.go file that requires sg Storage.
How to correctly describe / implement this Storage so that it can be transferred there? Can someone post an example?

type Storage interface {
  StorePurchases(ctx context.Context, sp []*Purchase) ([]*Purchase, error)
  StoreSubscriptionPurchases(ctx context.Context, sp []*SubscriptionPurchase) ([]*SubscriptionPurchase, error)
}

func NewValidate(sg Storage, applePassword string, gc IAPGoogleConfig) *Validate {
  return &Validate{
    Storage:       sg,
    ApplePassword: applePassword,
    GoogleConfig:  gc,
  }
}

with applePassword and IAPGoogleConfig it's clear

googleConfig := validate.IAPGoogleConfig{
    ClientEmail: "[email protected]",
    PrivateKey:  "123456789abcdefg",
  }

NewValidate(STORAGE,  "",  googleConfig)

what should STORAGE look like?

Answer 1

Judging by the methods of the Storage interface, it is necessary for this library to be able to save subscription / payment data to your database.
You can start by making an empty implementation, see what parameters you will receive / what you will need, and there you will already figure out how it is more convenient for you to save the data.
Let's say you store data in MySQL... then the implementation might look like this

type MySQLStorage struct {
    db *sql.DB
}

func NewMySQLStorage(db *sql.DB) *MySQLStorage {
    return &MySQLStorage{
        db: db,
    }
}

func (sg *MySQLStorage) StorePurchases(ctx context.Context, sp []*Purchase) ([]*Purchase, error) {
    for _, p := range sp {
        fmt.Printf("%+v\n", p)
    }

    return sp, nil
}

func (sg *MySQLStorage) StoreSubscriptionPurchases(ctx context.Context, sp []*SubscriptionPurchase) ([]*SubscriptionPurchase, error) {
    for _, p := range sp {
        fmt.Printf("%+v\n", p)
    }

    return sp, nil
}

those. challenge could be like this

db := connectToDB...
sg := NewMySQLStorage(db)
NewValidate(sg  "",  googleConfig)