


Detailed explanation of PHP closure function, detailed explanation of PHP closure function_PHP tutorial
Detailed explanation of PHP closure function, detailed explanation of PHP closure function
Anonymous function is also called closure function (closure allows the creation of a function without specifying it, The value most commonly used as a callback function parameter
.The closure function does not have a function name. You can directly pass in the variable in function(). When using it, the defined variable will be treated as a function
$cl = function($name){ return sprintf('hello %s',name); } echo $cli('fuck')`
Call directly through the variable name defined as an anonymous function
echo preg_replace_callback('~-([a-z])~', function ($match) { return strtoupper($match[1]); }, 'hello-world');`
use
$message = 'hello'; $example = function() use ($message){ var_dump($message); }; echo $example(); //输出hello $message = 'world'; //输出hello 因为继承变量的值的时候是函数定义的时候而不是 函数被调用的时候 echo $example(); //重置为hello $message = 'hello'; //此处传引用 $example = function() use(&$message){ var_dump($message); }; echo $example(); //输出hello $message = 'world'; echo $example(); //此处输出world //闭包函数也用于正常的传值 $message = 'hello'; $example = function ($data) use ($message){ return "{$data},{$message}"; }; echo $example('world');
example
class Cart{ //在类里面定义常量用 const 关键字,而不是通常的 define() 函数。 const PRICE_BUTTER = 1.00; const PRICE_MILK = 3.00; const PRICE_EGGS = 6.95; protected $products = []; public function add($product,$quantity){ $this->products[$product] = $quantity; } public function getQuantity($product){ //是否定义了 return isset($this->products[$product])?$this->products[$product]:FALSE; } public function getTotal($tax){ $total = 0.0; $callback = function($quantity,$product) use ($tax , &$total){ //constant 返回常量的值 //__class__返回类名 $price = constant(__CLASS__."::PRICE_".strtoupper($product)); $total += ($price * $quantity)*($tax+1.0); }; //array_walk() 函数对数组中的每个元素应用用户自定义函数。在函数中,数组的键名和键值是参数 array_walk($this->products,$callback); //回调匿名函数 return round($total,2); } } $my_cart = new Cart(); $my_cart->add('butter',1); $my_cart->add('milk',3); $my_cart->add('eggs',6); print($my_cart->getTotal(0.05));
The above is the relevant content about PHP closure function. I hope it will be helpful to everyone's learning.
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The main advantages of using database storage sessions include persistence, scalability, and security. 1. Persistence: Even if the server restarts, the session data can remain unchanged. 2. Scalability: Applicable to distributed systems, ensuring that session data is synchronized between multiple servers. 3. Security: The database provides encrypted storage to protect sensitive information.

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.

SessionID is a mechanism used in web applications to track user session status. 1. It is a randomly generated string used to maintain user's identity information during multiple interactions between the user and the server. 2. The server generates and sends it to the client through cookies or URL parameters to help identify and associate these requests in multiple requests of the user. 3. Generation usually uses random algorithms to ensure uniqueness and unpredictability. 4. In actual development, in-memory databases such as Redis can be used to store session data to improve performance and security.

Managing sessions in stateless environments such as APIs can be achieved by using JWT or cookies. 1. JWT is suitable for statelessness and scalability, but it is large in size when it comes to big data. 2.Cookies are more traditional and easy to implement, but they need to be configured with caution to ensure security.

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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