PHP object-oriented cloning
One of the biggest disadvantages of PHP4 object-oriented is that it treats objects as another data type, which makes many common OOP methods unusable, such as design patterns. These OOP methods rely on passing objects to other class methods as references, rather than as values. Fortunately PHP solves this problem. All objects are now treated as references by default. But because all object pairs are treated as references rather than values, it is now harder to copy objects. If you try to copy an object, this will point to the address of the original object. To solve the duplication problem, PHP provides a method to clone the display object.
Examples are as follows:
First introduce the use of clone keyword to clone objects:
<!--?php class TestClone { public $name; public $num; function setName($na) { $this--->name = $na; } function getName() { return $this->name; } function setNum($nu) { $this->num = $nu; } function getNum() { return $this->num; } } $test = new TestClone(); $test->setName("tianxin"); $test->setNum(123456); echo $test->getName(); echo $test->getNum()." "; $test2 = clone $test; $test2->setName("liwei"); echo $test->getName(); echo $test->getNum()." "; echo $test2->getName(); echo $test2->getNum(); ?>Running results:
tian123456 tian123456 xia123456
From the running results, we can see that if test2 does not modify the name. Although the two objects test and test2 are different objects, they have the same attributes, and changing the attributes of the test2 object will not affect the attributes of the test object. Therefore, it can be concluded that cloning is passing by value, not a simple reference.
PHP5 defines a special method name "__clone()" method, which is automatically called when an object is cloned. Using the "__clone()" method will create an object with the same properties and methods as the original object. If If you want to change the content of the original object after cloning, you need to rewrite the original attributes and methods in __clone(). The "__clone()" method can have no parameters, and it automatically contains two pointers, $this and $that, $this points to the copy, while $that points to the original;
<!--?php class TestClone { public $name; public $num; function setName($na) { $this--->name = $na; } function getName() { return $this->name; } function setNum($nu) { $this->num = $nu; } function getNum() { return $this->num; } function __clone() { $this->name = "huang"; } } $test = new TestClone(); $test->setName("tian"); $test->setNum(123456); echo $test->getName(); echo $test->getNum()." "; $test2 = clone $test; // $test2->setName("xia"); echo $test->getName(); echo $test->getNum()." "; echo $test2->getName(); echo $test2->getNum(); ?>
Running results:
tian123456 tian123456 huang123456
<!--?php class Person { // 下面是人的成员属性 var $name; // 人的名字 var $sex; // 人的性别 var $age; // 人的年龄 // 定义一个构造方法参数为属性姓名$name、性别$sex 和年龄$age 进行赋值 // function __construct($name="", $sex="",$age="") function __construct($name, $sex, $age) { $this--->name = $name; $this->sex = $sex; $this->age = $age; } // 这个人可以说话的方法, 说出自己的属性 function say() { echo "我的名字叫:" . $this->name . " 性别:" . $this->sex . " 我的年龄是:" . $this ->age . " "; } // 对象克隆时自动调用的方法, 如果想在克隆后改变原对象的内容,需要在__clone()中重写原来的属性和方法。 function __clone() { // $this 指的复本p2, 而$that 是指向原本p1,这样就在本方法里,改变了复本的属性。 $this->name = "我是复制的张三$that->name"; // $this->age = 30; } } $p1 = new Person ( "张三", "男", 20 ); $p2 = clone $p1; $p1->say (); $p2->say (); ?>
Result after running:
我的名字叫:张三 性别:男 我的年龄是:20 我的名字叫:我是复制的张三 性别:男 我的年龄是:20

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Implementing custom session processing in PHP can be done by implementing the SessionHandlerInterface interface. The specific steps include: 1) Creating a class that implements SessionHandlerInterface, such as CustomSessionHandler; 2) Rewriting methods in the interface (such as open, close, read, write, destroy, gc) to define the life cycle and storage method of session data; 3) Register a custom session processor in a PHP script and start the session. This allows data to be stored in media such as MySQL and Redis to improve performance, security and scalability.

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To protect the application from session-related XSS attacks, the following measures are required: 1. Set the HttpOnly and Secure flags to protect the session cookies. 2. Export codes for all user inputs. 3. Implement content security policy (CSP) to limit script sources. Through these policies, session-related XSS attacks can be effectively protected and user data can be ensured.

Methods to optimize PHP session performance include: 1. Delay session start, 2. Use database to store sessions, 3. Compress session data, 4. Manage session life cycle, and 5. Implement session sharing. These strategies can significantly improve the efficiency of applications in high concurrency environments.

Thesession.gc_maxlifetimesettinginPHPdeterminesthelifespanofsessiondata,setinseconds.1)It'sconfiguredinphp.iniorviaini_set().2)Abalanceisneededtoavoidperformanceissuesandunexpectedlogouts.3)PHP'sgarbagecollectionisprobabilistic,influencedbygc_probabi

In PHP, you can use the session_name() function to configure the session name. The specific steps are as follows: 1. Use the session_name() function to set the session name, such as session_name("my_session"). 2. After setting the session name, call session_start() to start the session. Configuring session names can avoid session data conflicts between multiple applications and enhance security, but pay attention to the uniqueness, security, length and setting timing of session names.


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