What are the access control levels for PHP functions?

There are three access control levels for PHP functions: public, protected, and private. Public functions can be accessed from anywhere, protected functions are only accessible to its own class and subclasses, and private functions are only accessible to its own class. When modifying the access control level, just add the corresponding keywords before the function declaration, such as public function, protected function, private function.

Access control level of PHP function

The access control level of PHP function determines which parts of the function can be accessed. It allows us to restrict access to functions, thereby improving the maintainability and security of our code.

Access control levels

There are three access control levels in PHP:

• public: Functions can be accessed from any Place visit.
• protected: A function can only be accessed from the class in which the function is located and its subclasses.
• private: Functions can only be accessed from the class in which the function is located.

Syntax

When modifying the access control level, just add the corresponding keyword before the function declaration.

// public 函数
public function myPublicFunction() {
    // ...
}

// protected 函数
protected function myProtectedFunction() {
    // ...
}

// private 函数
private function myPrivateFunction() {
    // ...
}

Practical case

Suppose we have a class User for storing user data. We want to allow access to user data only through the public methods of this class. To achieve this, we will set the function that gets user data to protected:

class User {
    protected $name;
    protected $email;

    public function getName() {
        return $this->name;
    }

    public function getEmail() {
        return $this->email;
    }
}

Now other classes can access getName() and # through the User object ##getEmail() method, but there is no direct access to the $name and $email properties.

Note

By default, the access control level of PHP functions is public.
• If an attempt is made to access a private or protected function, a
• Fatal Error will be raised.
Protected functions can be accessed in derived classes via
• parent::.
Consider using access control levels to protect access to sensitive data and functionality. Proper use of access control can improve code security.

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