How to use Go language to develop the delivery fee calculation function of the ordering system

How to use Go language to develop the delivery fee calculation function of the ordering system

Overview

In a complete ordering system, in addition to the user ordering In addition to the meal and payment functions, the calculation of delivery fees is also an essential part. This article will use Go language to develop the delivery fee calculation function of a simple ordering system and provide specific code examples.

Design ideas

Before designing the delivery fee calculation function, we need to clarify the following points:

1. The delivery fee calculation method: The delivery fee calculation method can be It is determined based on specific needs and can be calculated based on distance, order amount or other conditions. In this example, we will use distance as the way to calculate delivery fees.
2. Get the user address and business address: In order to calculate the delivery fee, we need to get the user address and business address. The user address can be obtained through the form in the front-end page, and the business address can be saved in the database or configuration file.
3. Call the map API to get the distance: In order to calculate the distance between the user and the business, we can call the map API to get the actual distance. In this example, we will use the Amap API.

Code implementation

The following is a sample code that uses Go language to develop the delivery fee calculation function of the ordering system:

package main

import (
    "encoding/json"
    "fmt"
    "io/ioutil"
    "net/http"
)

const (
    AMapAPIKey = "your_amap_api_key"
)

type DistanceResponse struct {
    Status string `json:"status"`
    Info   string `json:"info"`
    Count  string `json:"count"`
    Route  struct {
        Orgin     string `json:"origin"`
        Destination   string `json:"destination"`
        Distance   float64 `json:"distance"`
        Duration   float64 `json:"duration"`
    } `json:"route"`
}

func GetDistance(origin, destination string) (float64, error) {
    url := fmt.Sprintf("https://restapi.amap.com/v3/distance?origins=%s&destination=%s&output=json&key=%s",
        origin, destination, AMapAPIKey)
    
    resp, err := http.Get(url)
    if err != nil {
        return 0, err
    }
    defer resp.Body.Close()

    body, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        return 0, err
    }
    
    var distanceResponse DistanceResponse
    err = json.Unmarshal(body, &distanceResponse)
    if err != nil {
        return 0, err
    }

    return distanceResponse.Route.Distance, nil
}

func CalculateDeliveryFee(origin, destination string) (float64, error) {
    distance, err := GetDistance(origin, destination)
    if err != nil {
        return 0, err
    }

    deliveryFee := distance * 0.01 // 假设配送费为每公里0.01元

    return deliveryFee, nil
}

func main() {
    origin := "用户地址"
    destination := "商家地址"

    deliveryFee, err := CalculateDeliveryFee(origin, destination)
    if err != nil {
        fmt.Println("计算配送费失败：", err)
    }

    fmt.Println("配送费：", deliveryFee, "元")
}

In the above code, we first define A DistanceResponse structure is created to parse the distance data returned from the Amap API. Then call the Amap API through the GetDistance function to get the actual distance. Next, in the CalculateDeliveryFee function, the delivery fee is calculated based on the obtained distance, where we assume that the delivery fee is 0.01 yuan per kilometer. Finally, the CalculateDeliveryFee function is called in the main function to calculate the delivery fee and print the output.

It should be noted that the AMapAPIKey variable in the above code needs to be replaced with your own AMAP API key.

Summary

By using Go language, we can easily develop the delivery fee calculation function of a food ordering system. In the above code example, we show how to call the Amap API to obtain the actual distance and calculate the delivery fee based on the distance. Through this simple example, you can conduct more complex development based on Go language in the actual ordering system.

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