How to use Go language to write the user account recharge module in the door-to-door cooking system?

As the takeout market becomes increasingly mature, home cooking has become the first choice for many families for dinner. As a provider of door-to-door cooking services, it is essential to provide reliable user account recharge. This article will introduce how to use Go language to write the user account recharge module in the door-to-door cooking system.

1. Design

When designing the recharge module, we need to consider the following aspects:

1. The data structure to be used

In the recharge module, we need to store the user's balance before and after recharging. Therefore, we can use the following data structure:

type Account struct {
    UserID int
    Balance float64
}

Here we use UserID to identify the user, and Balance to store its account balance.

2. Functions to be implemented

In the user recharge module, we need to implement the following functions:

• Query the current user balance
• Recharge
• Deduction

Considering that multiple account operations may be involved in the same transaction, we recommend using transaction management database operations.

2. Implementation

In specific implementation, we can use the ORM framework provided by the Go language, such as GORM.

1. Installing GORM

It is very convenient to install GORM in Go language. Just run the following command in the terminal:

go get -u github.com/jinzhu/gorm

2. Connect to database

Before using the GORM framework, we need to connect to the database first. We can use MySQL as the database and use MySQL in the Go language. We can use the third-party library go-sql-driver/mysql.

import (
    "fmt"
    "github.com/jinzhu/gorm"
    _ "github.com/go-sql-driver/mysql"
)

DB, err := gorm.Open("mysql", "username:password@tcp(127.0.0.1:3306)/database_name?charset=utf8mb4&parseTime=True&loc=Local")
if err != nil {
    panic(fmt.Sprintf("database connection error: %v", err))
}

In the above code, we need to replace username, password and database_name with the specific database username, password and database name . Among them, tcp(127.0.0.1:3306) indicates connecting to the local database, and the port is 3306. charset=utf8mb4&parseTime=True&loc=Local means using utf8mb4 character encoding, turning on time parsing and local time zone storage.

3. Define the data model

In order to better manage the data in the database, we need to define the corresponding data model. In the recharge module, we need to define the account data model.

type Account struct {
    gorm.Model
    UserID int
    Balance float64
}

In this data model, we use gorm.Model structure embedding to get ID, CreatedAt, UpdatedAt# Basic fields such as ## and DeletedAt. At the same time, we define the UserID and Balance fields for this data model.

Recharge

When implementing the recharge function, we need to query the user account first. If the account does not exist, we need to create it. We then add the recharge amount to the balance. Finally, we save the updated data to the database.

func Recharge(userID int, amount float64) error {
    account := Account{}
    res := DB.Where("user_id = ?", userID).First(&account)
    if res.Error != nil && res.Error != gorm.ErrRecordNotFound {
        return res.Error
    }
    if res.Error == gorm.ErrRecordNotFound {
        account.UserID = userID
        account.Balance = amount
        res = DB.Create(&account)
        if res.Error != nil {
            return res.Error
        }
    } else {
        account.Balance += amount
        res = DB.Save(&account)
        if res.Error != nil {
            return res.Error
        }
    }
    return nil
}

In this recharge function, we first query the user account through

DB.Where("user_id = ?", userID).First(&account). If the account does not exist, we create a new account; otherwise, we query the account based on the user ID and add the recharge amount amount to the account balance. Finally, we save the updated data to the database through DB.Save(&account).

Deduction

When implementing the deduction function, we need to perform some data verification, such as whether the account balance is sufficient for payment and whether the deduction amount is greater than zero. If the data verification passes, the deduction amount will be deducted from the balance and saved in the database.

func Deduct(userID int, amount float64) error {
    if amount <= 0 {
        return errors.New("invalid deduct amount")
    }

    account := Account{}
    res := DB.Where("user_id = ?", userID).First(&account)
    if res.Error != nil {
        return res.Error
    }

    if account.Balance-amount < 0 {
        return errors.New("insufficient balance")
    }

    account.Balance -= amount
    res = DB.Save(&account)
    if res.Error != nil {
        return res.Error
    }

    return nil
}

In this deduction function, we first verify the deduction amount

amount to ensure that it is greater than zero. Then, we query the user account and determine whether the balance is sufficient to support the deduction. Finally, we deduct the debit amount from the balance and save the updated data to the database.

3. Summary

This article introduces how to use Go language to write the user account recharge module in the door-to-door cooking system. We use the GORM framework to manage data in the database and provide specific code examples to implement user account recharge and debit functions. Of course, in actual development, we can also make corresponding modifications and expansions according to our own needs.

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