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Sergey Zhuk:
Cancelling ReactPHP Promises With Timers
Aug 31, 2017 @ 12:08:35

Sergey Zhuk has a new post to his site continuing on from a previous article about promises in ReactPHP. In this latest post he shows how you can use timers to cancel the execution of promises if their execution time grows too large.

At first, let’s refresh in memory what is Promise. A promise represents a result of an asynchronous operation. You can add fulfillment and error handlers to a promise object and they will be invoked once this operation has completed or failed. Check this article to learn more about promises.

Promise is a very powerful tool which allows us to pass around the code the eventual results of some deferred operation. But there is one problem with promises: they don’t give us much control.

He then shares the code required to make a simple "Hello world" promise and a handler for when it's cancelled. He then shows how to use the PromiseTimer functionality in ReactPHP to set a timeout on the promise instance and automatically call the cancellation event when it reaches that limit. He also includes a reminder that, in the cancellation handling of the promise it's a good idea to close out and cancel any other resources that may have been in use. The post ends with an example of how you can stack other functionality on the timeout using methods like "then" and "otherwise".

tagged: reactphp timer promise promisetimer tutorial asynchronous

Link: http://seregazhuk.github.io/2017/08/22/reactphp-promise-timers/

Lorna Mitchell:
Handling Incoming Webhooks in PHP
Jul 27, 2017 @ 12:27:14

Lorna Mitchell has a quick post to her site sharing a method she uses for handling incoming web hooks requests in PHP and the process her code usually uses for parsing the incoming message.

An increasing number of applications now offer webhooks as an integration, often in addition to an API. The classic example, familiar to most developers, is the GitHub webhooks which can notify your other systems such as CI tooling that a new commit has been added to a branch.

[...] Whether it's your source control, updates from your IoT sensors, or an event coming from another component in your application, I have some Opinions (TM) about handling webhooks, so I thought I'd write them down and include some code as well, since I think this is an area that many applications will need to work with.

She talks about the receive/respond workflow she recommends: immediately storing and acknowledge the data and then responding out of band (asynchronously). She includes a bit of example code that reads in the raw input from the incoming message, saves it and then responds back with a 200 response code back to the waiting service. She then talks about the out-of-band processing the message could use, evaluating the contents and acting on them as a result.

tagged: webhooks incoming processing asynchronous response tutorial

Link: https://lornajane.net/posts/2017/handling-incoming-webhooks-in-php

SitePoint PHP Blog:
How to Scan Fingerprints with Async PHP and React Native
Jun 07, 2017 @ 11:52:09

The SitePoint PHP blog has posted a tutorial from Christopher Pitt with another interesting use of PHP: using it and React to scan fingerprints to aid in multi-factor authentication.

We live in interesting times. A short while ago, a company called OfferZen announced a new, programmable credit card. It’s been a long time since I was this excited to get my hands on a piece of tech. My mind has been brimming with ideas ever since.

So, I decided to write about one of them!

I’m going to describe the process of building custom multi-factor authentication for all transactions. I don’t want to do the usual (and boring on its own) SMS or push notification one-time-password stuff. I want to build a fingerprint scanner right into my phone. [...] In this tutorial, we’re going to look at how to set up a simple iOS app using React Native. We will also set up an asynchronous HTTP server, with a web socket connection to the app.

He starts by taking some time to introduce React Native for those not familiar with it and what it brings to the table. He then walks through the installation of React Native and how to install the TouchID package using yarn. He also includes some simple JS code you can use to ensure it's all working. Next up he uses PHP to create an asynchronous server with the amphp/aerys package (this code). He creates the server with a "scan" endpoint handlers for opening the connection, performing the handshake and reacting to incoming data. Then he brings them together, connecting React and PHP, and sets up a script to wait for fingerprints. Code is included to perform the validation of the fingerprint and the end result should look something like this.

tagged: react reactnative fingerprint scanner mobile asynchronous tutorial

Link: https://www.sitepoint.com/scan-fingerprints-async-php-react-native/

SitePoint PHP Blog:
Writing Async Libraries – Let’s Convert HTML to PDF
Feb 21, 2017 @ 09:58:05

The SitePoint PHP blog has another tutorial posted from author Christopher Pitt looking at writing async libraries with PHP. In this particular article he focuses on just one of many tasks an asynchronous library could perform: converting HTML to PDF documents.

I can barely remember a conference where the topic of asynchronous PHP wasn’t discussed. I am pleased that it’s so frequently spoken about these days. There’s a secret these speakers aren’t telling, though: "Making asynchronous servers, resolving domain names, interacting with file systems: these are the easy things. Making your own asynchronous libraries is hard. And it’s where you spend most of your time!"

The reason those easy things are easy is because they were the proof of concept – to make async PHP competitive with NodeJS. [...] Today, we’re going to look at a few ways to make your application code work well in an asynchronous architecture. Fret not – your code can still work in a synchronous architecture, so you don’t have to give anything up to learn this new skill. Apart from a bit of time…

He starts with some theory about things in the async world including callbacks, promises and what they might look like in PHP-land. He then starts in on the creation of the PDF files, creating a "Driver" class to handle some of the logic and using the Dompdf library to do the heavy lifting (the conversion from HTML to PDF). He walks through the code required for this class then moves on to the code, using the Amp project, to handle the async operations. He then creates a simple set of web accessible endpoints that call the Driver class with some basic attributes and performing the conversion. He ends the post talking about porting the parallel driver to other systems (such as ReactPHP) and a few simple steps if you need to move back to the synchronous world.

tagged: asynchronous conversion dompdf html pdf tutorial amp

Link: https://www.sitepoint.com/writing-async-libraries-lets-convert-html-to-pdf/

PHP Roundtable:
044: Asynchronous PHP
Apr 27, 2016 @ 09:23:05

The PHP Roundtable, with host and PHP community member Sammy K Powers, has posted a new episode featuring a discussion about Asynchronous PHP. In this show Sammy is joined by guests Christopher Pitt, Sara Golemon and Aaron Piotrowski.

Async? Isn't that like AJAX in Javascript or something? Most PHP developers encounter asynchronous code for the first time in Javascript, but not many are aware that PHP can do async too. We discuss asynchronous programming in PHP and how we might be able to implement it in our own projects using various libraries. We also take a look at how async features could be added to PHP core to support async natively.

There's plenty of detail in the show notes for this episode covering all of the topics mentioned and links to some other resources you can use to find out more about asynchronous development in PHP. You can listen/watch this latest episode either through the in-page video player or directly on YouTube. If you enjoy the show, be sure to subscribe to their feed and follow them on Twitter for the latest updates when new shows are released.

tagged: phproundtable podcast ep44 asynchronous code discussion

Link: https://www.phproundtable.com/episode/asynchronous-php

SitePoint PHP Blog:
Websockets in Your Synchronous Site
Feb 26, 2016 @ 11:03:53

The SitePoint PHP blog has a new tutorial from Christopher Pitt showing you how to integrate websockets into your application for asynchronous, real-time functionality. His method makes use of a service called Socketize (with a free tier available).

Asynchronous architecture is common in other programming languages, but it’s only just finding its feet in PHP. The trouble is that this new architecture comes with a cost.

I don’t talk about that cost enough. [...] When I recommend frameworks like Icicle, ReactPHP, and AMPHP, the obvious place to start with them is to create something new. [...] It takes a lot of work to integrate new, asynchronous features into existing applications. Often there are good reasons and great benefits, but a rewrite is always a hard-sell. [...] I’m going to show you a Sockets-as-a-Service service, called Socketize.

He walks you through the setup of the code and account to create a simple CRUD (create, read, update, delete) system for a deck of cards. He starts with a simple synchronous API spitting back JSON of the card data. Then he creates the frontend client (simple Javascript) to fetch the data and append the values to the page. Next comes the asynchronous handling - he shows the creation of the Socketize account, setting up a new application (with keys) and making use of the SocketizeJavascript client to create the websocket and hook it all together.

tagged: websockets asynchronous socketize application frontend service thirdparty

Link: http://www.sitepoint.com/websockets-in-your-synchronous-site/

Symfony Finland:
Going Async in Symfony Controllers
Feb 22, 2016 @ 10:50:25

On the Symfony Finland site Jani Tarvainen has posted a tutorial showing you how to create asynchronous controller handling in a Symfony-based application.

Asynchronous programming has become a synonym for high performance in server side web applications in the recent years. This is largely due to the rising popularity of JavaScript and Node.js, in which everything is async by default. [...] So asynchronous programming does not push your computer into overdrive to enable higher performance. What it can do is help the computer to use it's resources more efficiently, by removing time spent waiting.

He then talks about PHP's typical flow model - synchronous and single-threaded. While it does make it simpler to debug/understand it also limits it and can cause higher processing times. Thanks to some other projects, however, asynchronous development with PHP has become more of a reality. He shows how to use one of these projects, Icicle, and its coroutines functionality to make a Symfony controller that handles calls to a sayHello method asynchronously, returning messages in a fraction of the normal processing time.

tagged: asynchronous controller tutorial icicle wait symfony

Link: https://www.symfony.fi/entry/going-async-in-symfony-controllers

SitePoint PHP Blog:
An Introduction into Event Loops in PHP
Sep 10, 2015 @ 10:06:55

The SitePoint PHP blog has posted a tutorial from Christopher Pitt introducing you to using event loops in PHP, a feature that allows for asynchronous processing, executing code while waiting for other code to finish.

PHP developers are always waiting for something. Sometimes we’re waiting for requests to remote services. Sometimes we’re waiting for databases to return rows from a complex query. Wouldn’t it be great if we could do other things during all that waiting?

If you’ve written some JS, you’re probably familiar with callbacks and DOM events. And though we have callbacks in PHP, they don’t work in quite the same way. That’s thanks to a feature called the event loop.

He starts by explaining event loops with an example from a language that naturally supports it - Javascript. He includes another example using the setTimeout function in Javascript to show a simple loop but points out that PHP just doesn't support this same kind of handling (code included). So, how can you simulate the loop like in JS? He links to and includes a examples of two libraries that could be dropped in and used to do the hard work behind the scenes of the looping:

He suggests that PHP developer "get out of the single threaded mindset" and work in ways to handle asynchronous processing into their code to improve performance and flexibility.

tagged: event loop javascript library icicle reactphp asynchronous processing

Link: http://www.sitepoint.com/an-introduction-into-event-loops-in-php/

Cees-Jan Kiewiet:
AWS PHP SDK Asynchronously
Jun 30, 2015 @ 11:31:15

Cees-Jan Kiewiet has a new post today talking about some interesting trickery he was able to do with the AWS (Amazon Web Services) PHP SDK to allow requests to be made asynchronously.

Just got off the AWS SDK for PHP Office Hour hangout and it was great talking with both team members Jeremy and Michael. And one of the things we talked about was async access to the AWS services using the PHP SDK. The goal of this post is to get the AWS PHP SDK client working asynchronously.

He starts with brief instructions on getting the SDK installed (via Composer) along with a library of his own that brings in a few other dependencies. The ReactPHP event loop is what makes the asynchronous connections possible. He includes the code to create the new handler stack and how to use it to make the asynchronous calls. A demo screencast is also included in the post to illustrate the output from a simple set of requests.

tagged: aws amazon sdk asynchronous connection reactphp event loop tutorial

Link: http://blog.wyrihaximus.net/2015/06/aws-php-sdk-asynchronously/

Christopher Pitt:
Co-operative PHP Multitasking
Mar 30, 2015 @ 12:47:41

Christopher Pitt has posted a new article on Medium.com about when an "array is like an adventure" when in the context of co-operative PHP multitasking. In it he shows how to make code work asynchronously with out the use of extensions, only generators.

Last week I got the opportunity to share recent work with my colleagues, at SilverStripe. I was going to present Async PHP today, but since I covered ReactPHP last week; I decided to talk about something slightly different. So here’s a post about cooperative multitasking.

He starts with some basic arrays and other things that act like them and can be iterated through (Traversable). He talks about implementing custom iterators to act the same way and the use of IteratorAggregate to "cheat" a bit when making them. The he gets into generators, showing how they can be used to iterate similarly. He shows how it's possible to send data to a generator, throwing exceptions inside them and the use of "coroutines" to create asynchronous code. He builds up a queue system with this method and shows how they execute with some simple echo output. He also shows the use of RecoilPHP, another coroutine-based library, to replace the main kernel for a ReactPHP script. He also mentions IcicleIO as another option.

tagged: cooperative multitasking asynchronous code coroutine generator

Link: https://medium.com/@assertchris/co-operative-php-multitasking-ce4ef52858a0