Event extensions in PHP8.0

As a popular server-side programming language, PHP has ushered in its latest version-PHP8.0 in its continuous development. Although this version has only been released for a short time, it has already brought many new functions and features, among which event expansion is one of them. This article will introduce the event extension in PHP8.0 in detail and understand its role and usage.

1. Event-driven programming

First of all, you need to understand the concept of event-driven programming. In the traditional programming model, a program is composed of statements that are executed sequentially. That is to say, the program flow is executed in a sequence predefined by the programmer. However, in event-driven programming, the program is not composed of sequentially executed statements, but a series of "events". The programmer defines the event handler. When an event occurs, the program will automatically execute the corresponding event. processor. In this way, program execution becomes more flexible and efficient.

2. Overview of event expansion

In PHP8.0, event expansion was introduced. It provides support for event-driven programming for PHP applications. This extension allows developers to define their own events and then use them in their applications. At the same time, it also provides many event-related functions and classes, which can help developers use events more conveniently.

3. Usage of event extension

1. Installation

Before you start using event extension, you need to make sure that PHP8.0 has been installed and events are enabled. Extension. You can verify whether it has been enabled by running the following command:

php -m | grep event

If there is the word "event" in the result, it means that event expansion has been enabled. Otherwise, you need to add the following line to the php.ini file:

extension=event

2. Using

First, you need to create the event object and event base kind. An event class can be created using the following code:

use EventEvent;

class MyEvent extends Event
{

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}

Finally, associate the event handler with the event ：

$myEvent->addHandler('myEventHandler');

In this way, when the event occurs, the event handler will be automatically executed. You can use the following code to trigger events:

$myEvent->trigger();

4. Event extension API

The event extension in PHP8.0 provides many Event-related functions and classes, the following are worth noting:

1. Event

The Event class is the event base class, which defines the basic attributes and method.

Attributes:

• type: The type of event.
• propagationStopped: The stop sign of the event.

Method:

• __construct(): Constructor, used to initialize events.
• getType(): Get the type of event.
• stopPropagation(): Stop the propagation of events.
• isPropagationStopped(): Check whether the event has stopped propagating.

2. EventBase

The EventBase class is the base class for event processing and is used to manage event loops and event handlers.

Method:

• __construct(): Constructor, used to initialize the event loop.
• loop(): Start the event loop.
• exit(): Exit the event loop.
• priorityInit(): Initialize the priority of the event handler.
• dispatch(): dispatch event handler.
• reInit(): Reinitialize variables.

3. EventConfig

The EventConfig class is used to configure events.

Method:

• __construct(): Constructor, used to initialize configuration.
• setMaxDispatchInterval(): Set the maximum dispatch interval of the event handler.
• setMaxIterations(): Set the maximum number of iterations of the event handler.

4. EventBufferEvent

The EventBufferEvent class is used to cache events and can achieve efficient data transmission in applications.

Attributes:

• input: Input cache.
• output: output cache.
• inputCallback: Input callback.
• outputCallback: Output callback.
• errorCallback: error callback.

Method:

• __construct(): Constructor, used to initialize cache events.
• enable(): Enable cache events.
• disable(): Disable cache events.
• getEnabled(): Check whether cache events are enabled.

5. Summary

Event extension is one of the important features in PHP8.0, which provides developers with support based on event-driven programming. It provides many event-related functions and classes to help developers use events more conveniently. In practical applications, event extensions can be used to implement efficient data transmission, server-side push and other functions. Therefore, it is very necessary to understand and master the usage and API of event extensions.

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