golang package hidden

As more and more developers turn to the Go language for development, the issue of golang package management has gradually been put on the agenda. Among them, package hiding (Package Hiding) is a very important function. It can help us hide some functions that have internal implementation details or are considered obsolete in Go language projects, thereby improving the readability and Use security.

This article will introduce the principles, usage scenarios and implementation methods of golang package hiding. I hope it can help readers deeply understand this function and apply it to actual projects.

1. What is package hiding?

Before understanding package hiding, you need to first understand what a package (Package) in golang is and its characteristics. In Golang, every file belongs to a package, and in a package, files can access each other's internal variables, functions, methods and other public (Public) content.

However, in some cases, we do not want some public variables or functions to be accessed by other packages, because they may be internal implementation details of the project or obsolete and abandoned functions, and external access will bring security hidden dangers or impact on other functions.

At this time, you need to use golang's package hiding function to hide some internally implemented or abandoned functions for internal use only and not exposed to the outside world.

2. Usage scenarios of package hiding

1. The underlying implementation of hidden service startup

In web development, we often need to implement a web server service . However, in a production environment, the existence of security facilities such as firewalls means that the web server service can only use fixed ports for listening and cannot be configured through command line parameters and other methods. At this time, if the port number is directly exposed to the outside, it may cause security risks, and attackers can directly use the port number to launch attacks.

In order to solve the problem, we can use the package hiding function to hide the underlying implementation of service startup, and only provide an interface that is not exposed to the outside world for use by other modules, thus ensuring the security of the service.

2. Hide obsolete functions and variables

When we delete some obsolete functions and variables in the project, in order to prevent other modules from using these deleted contents, We can use the package hiding function to hide them and no longer use them in the project to avoid security risks.

3. How to implement package hiding

1. Use lowercase letters as identifier prefix

In golang, if the identifier of a variable or function The first letter of is a lowercase letter, then it is a private variable or function inside the package, which is only used within the package and is not exposed to the outside world.

For example:

package utils

import "fmt"

// 私有变量
var _privateVariable = "I am a private variable"

// 公共变量
var PublicVariable = "I am a Public variable"

// 私有函数
func _privateFunction() {
    fmt.Println("I am a private function")
}

// 公共函数
func PublicFunction() {
    fmt.Println("I am a Public function")
    _privateFunction()
}

In this example, the variable _privateVariable and the function _privateFunction are defined as private variables and private functions inside the package and can only be used inside the utils package. The variable PublicVariable and the function PublicFunction are public and can be referenced and used by other packages.

2. Use "_" blank identifier

In golang, the "_" (underscore) identifier is defined as a special identifier, which can be used Placeholders or variables that are used only once and therefore can be used to hide variables and functions that do not need to be exported.

For example:

package utils

import "fmt"

// 私有变量
var (
    _privateVariable = "I am a private variable"
    _unusedVariable  = "I am a unused variable"
)

// 公共函数
func PublicFunction() {
    fmt.Println("I am a Public function")
}

In this example, the variable _unusedVariable is defined as a variable that does not need to be exported and is not used. By using the "_" blank identifier, it avoids its impact on other The impact of the package.

4. Summary

Package hiding is a very important function in golang. It can help us hide some functions that have internal implementation details or are considered obsolete, and improve the visibility of the code. readability and safe to use. By using lowercase letters as identifier prefixes and "_" blank identifiers, we can easily define and hide variables and functions that do not need to be exported, making the entire project more robust and secure.

The above is the detailed content of golang package hidden. For more information, please follow other related articles on the PHP Chinese website!