Asynchronous Programming with ReactPHP

What is asynchronous?

In general, asynchronous (pronounced ay-SIHN-kro-nuhs, from Greek asyn-, meaning "not with," and chronos, meaning "time") is an adjective describing objects or events that are not coordinated in time.

What is asynchronous?

Asynchronous means that a process operates independently of other processes.

Is PHP asynchronous?

 

 

No, PHP is synchronous

 

Process runs only as a result of some other process being completed or handing off operation.

Synchronous vs Asynchronous

Synchronous vs Asynchronous 


console.log('Test 1');

setTimeout(function() {
    console.log('Test 2');
}, 1);

console.log('Test 3');

function test1(){ echo 'Test 1' . PHP_EOL;}

function test2(){
    sleep(3);
    echo 'Test 2' . PHP_EOL;
}

function test3(){ echo 'Test 3' . PHP_EOL;}

test1();
test2();
test3();

JS

PHP

Synchronous vs Asynchronous

JS

PHP

Test 1 
Test 2 
Test 3
Test 1 
Test 3
Test 2

Introducing ReactPHP?

 

A low-level library for event-driven, non-blocking I/O programming with PHP.

What is ReactPHP?

 

We are not talking about the JavaScript  library

 

It is not a tool that  is used to make working with React and PHP easier

 

It's not a framework

What is ReactPHP?

  • 100% PHP
  • No extensions required
    • There are optional extensions 
  • Production ready
  • Supports PHP 5+
    •  Recommends latest version of PHP 7+ 
  • Aims to be technology neutral

 

What is ReactPHP?

ReactPHP is not a framework.

 

It's a set of independent components which means you take the parts you need.

 

 

Setting up ReactPHP

 

  • PHP
    • Supports legacy PHP 5.3+
  • Composer

 

$ composer require react/react

The Basics

 

Three Core Components: 

 

  • Event Loop
  • Promises
  • Streams

 

 

 

The Basics

 

 

Steps:

  • You create it once at the beginning of the program.
  • Set up it.
  • Run it once at the end of the program

The Event Loop

 

  • This is the core of ReactPHP
  • All other components use it
  • Responsible for handling asynchronous operations
  • Implements Reactor Pattern

 

 

 

The Event Loop

Register Event

 

Listen

 

Get notified so you can react to event

The Event Loop

Install 

 

 

Usage

 

 

$ composer require react/event-loop

$loop = React\EventLoop\Factory::create();

$loop->addPeriodicTimer(1, function () {
    echo "Test\n";
});

$loop->run();

The Event Loop

Example 

 

 

 

 

 


require 'vendor/autoload.php';

$loop = React\EventLoop\Factory::create();


echo "Test 1\n";

$loop->addTimer(3, function(){
    echo "Test 2\n";
});

echo "Test 3\n";

$loop->run();

The Event Loop

The Event Loop

  • run()
  • stop()
  • addTimer()
  • addPeriodicTimer()
  • cancelTimer()
  • futureTick()

 

 

 

 

  • addSignal()
  • removeSignal()
  • addReadStream()
  • addWriteStream()
  • removeReadStream()
  • removeWriteStream()

 

 

 

Other Methods

Streams

Allow you to process data in pieces

 

 

3 Types:

  • Readable (STDIN)
  • Writable (STDOUT)
  • Duplex (Socket)

 

 

 

Streams

require 'vendor/autoload.php';

$loop = React\EventLoop\Factory::create();
$stream = new \React\Stream\ReadableResourceStream(STDIN, $loop);


$stream->on('data', function($data){
    // process data *line by line*
});

$stream->on('end', function(){
    echo "finished\n";
});

$loop->run();

Streams

require 'vendor/autoload.php';

$loop = React\EventLoop\Factory::create();
$writable = new \React\Stream\WriteableResourceStream(STDOUT, $loop);


$writable->write('Test');
    
$loop->run();

Promises

Represents the eventual completion (or failure) of an asynchronous operation, and its resulting value

 

3 States:

  • Pending / Unfulfilled
  • Fulfilled
  • Failed

 

 

 

Promises

Promises

$deferred = new React\Promise\Deferred();

$promise = $deferred->promise();

$promise->then(
    function($data){
        //run code
    },
    function($data){
        //run code
    });

$deferred->reject('hello world');

Promises

require 'vendor/autoload.php';

function testPromise($url, $method)
{
    $deferred = new React\Promise\Deferred();
    $response = true;

    if ($response){
        $deferred->resolve($response);
    } else {
        $deferred->reject(new Exception('Failed'));
    }
    return $deferred->promise();
}


testPromise("http://eddie.com", "GET")->then(
    // fullfilled
    function($response){
        echo $response . PHP_EOL;
    },
    // rejected
    function(Exception $exception){
        echo $exception->getMessage() . PHP_EOL;
    }
);

Promises

Promises

Promises

  • then()
  • done()
  • otherwise()
  • always()

 

 

 

Other methods

More to ReactPHP

 

More Components

  • Network
    • Socket
    • Datagram
  • Protocol
    • HTTP
    • HTTPClient
    • DNS
  • Utility
    • Cache
    • PromiseTimer
    • ChildProcess
    • PromiseStream

 

 

 

Resources

 

  • https://reactphp.org/
  • https://github.com/reactphp/react/wiki/Users
  • https://leanpub.com/event-driven-php
  • https://sergeyzhuk.me/reactphp-series
  • Video Tutorials
    • https://www.youtube.com/results?search_query=reactphp
    • https://www.youtube.com/channel/UC3EThWvNp4EabJD7PyCOzGw

 

 

 

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