Golang framework in-depth understanding and troubleshooting

Golang Framework Troubleshooting: Routing configuration issues: Nested routes are placed in different routing groups or using regular expression matching. Middleware calling order issue: Use HandlerChain to control middleware execution order. Template parsing error: Make sure both the template file and the template reference have been resolved. Data model binding failed: Use labels to specify the corresponding relationship between form and model fields or customize the binding function. Database connection issues: Check connection information, database running status, and user access rights. HTTP status code error: Use the correct HTTP status code and check whether the middleware modifies the status code.

Golang framework in-depth understanding and troubleshooting

Introduction

Web development in Golang , using frameworks can simplify the development process and provide a large number of functions. However, developers may encounter various problems when using frameworks. This article will delve into troubleshooting common frameworks in Golang and provide solutions.

Troubleshooting

1. Routing configuration problem

// gin 框架中，路由组无法匹配嵌套路由
router.Group("/user").GET("/profile", userProfileHandler)
router.GET("/user/:id", userGetHandler)
// 尝试访问 /user/1 时，路由匹配 userProfileHandler

• Solution: Place nested routes in different route groups, or use regular expressions to match routes.

2. Middleware calling sequence problem

// 使用 gin 框架，中间件执行顺序不预期的
router.Use(middleware1)
router.Use(middleware2)
router.GET("/", indexHandler)

// 预期：middleware1 -> middleware2 -> indexHandler
// 实际：middleware2 -> middleware1 -> indexHandler

• Solution: Use HandlerFunc type Wrap middleware and use HandlerChain to control the execution order of middleware.

3. Template parsing error

// 使用 html/template 解析模板文件时，找不到模板
tmpl, err := template.ParseFiles("templates/index.html")
// err: template: templates/index.html:1:1: executing "templates/index.html" at <template>: could not find template "layout"

• Solution: Make sure that other templates referenced in the template file have been parsed, Or use the template.ParseGlob function to parse all template files at once.

4. Data model binding failed

// 使用 gorm 框架，无法为模型绑定表单数据
type User struct {
    ID       uint
    Username string
}

func createUserHandler(c *gin.Context) {
    var user User
    if err := c.Bind(&user); err != nil {
        // 数据模型绑定失败
    }
}

• Solution: Use structlayout tag Specify the corresponding relationship between form fields and model fields, or use a custom binding function.

5. Database connection problem

// 使用 gorm 框架，无法连接到数据库
db, err := gorm.Open("mysql", "user:password@tcp(localhost:3306)/database")
// err: failed to connect to the database

• Solution: Check whether the database connection information is correct and make sure the database is running , and the user has been granted access.

6. HTTP status code error

// 使用 gin 框架，返回了错误的 HTTP 状态码
c.JSON(500, gin.H{"message": "Internal Server Error"})
// 预期：HTTP 状态码 500
// 实际：HTTP 状态码 200

• Solution: Make sure to use the correct HTTP status code and check Whether the middleware modified the status code.

Practical case

Case description:Use the gin framework to process POST requests in routing, and use the gorm framework to save data to database.

Solution:

package main

import (
    "github.com/gin-gonic/gin"
    "gorm.io/gorm"
)

type Todo struct {
    ID          uint

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