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.

On the Hack blog there's a new post talking about async, a feature in Hack that allows for code to "cooperatively multitask". This gives the language a way to keep moving on in the execution without having to wait for things like database queries or remote file fetches to finish.

This is somewhat similar to threading, in that multiple code paths are executed in parallel, however it avoids the lock contention issues common to multithreaded code by only actually executing one section at any given moment. “What’s the use of that?”, I hear you ask. You’re still bound to one CPU, so it should take the same amount of time to execute your code, right? Well, that’s technically true, but script code execution isn’t the only thing causing latency in your application. The biggest piece of it probably comes from waiting for backend databases to respond to queries.

She gives the example of pulling in a remote file (HTTPS, where there's a bit more latency) and how to use async, await, WaitHandle, and Awaitable to work around the timing issue. She shows how to make a method asynchronous and how to join the results of the operation back up with the rest of the script. This includes the use of various "handles" including RescheduleWaitHandle, SleepWaitHandle and the AwaitAllWaitHandle. She shows the integration of a custom cURL handler that makes use of this processing, marked async, to multithread the requests to the remote server(s).

Jonathan Hill has posted the video of his recent presentation at the Atlanta PHP User Group, "Multi-tasking in PHP".

When it comes to multi-tasking and interacting with the operating system, PHP is no lightweight. In this December 6, 2012 presentation Jonathon Hill (@compwright) explores PHP's little-known POSIX, Process Control, and Semaphore extensions and shows you how to introduce a parallel dimension to your applications.

His presentation covers the use of multi-tasking to accomplish some common tasks in PHP (like batch processing or creating daemons). He talks about multi-processing vs multi-threading, forking, race conditions and semaphores.

You can watch the video of the presentation over on Vimeo and check out the software and links to other resources mentioned in the talk in this link bundle.

Nikita Popov has a new post to his blog about a new feature that will be coming in PHP 5.5 and how to use them, coroutines and generators, in an example application.

Coroutines on the other hand have received relatively little attention. The reason is that coroutines are both a lot more powerful and a lot harder to understand and explain. In this article I'd like to guide you through an implementation of a task scheduler using coroutines, so you can get a feeling for the stuff that they allow you to do. I'll start off with a few introductory sections. If you feel like you already got a good grasp of the basics behind generators and coroutines, then you can jump straight to the "Cooperative multitasking" section.

He starts with a look at generators, a piece of functionality that will allow PHP to, for example, more easily create iterators "on the fly." He then moves on to coroutines, added functions that you have two-way communication with generators instead of just pulling data from them. With the basics out of the way, he gets into the "cooperative multitasking" and a sample socket-based server he implements using some of the concepts.

The Atlanta PHP User Group has announced their December 2012 meeting happening on the 6th. The presenter this time will be Jonathan Hill covering multi-tasking in PHP.

When it comes to multi-tasking and interacting with the operating system, PHP is no lightweight. In this talk we’ll explore PHP’s little-known POSIX, Process Control, and Semaphore extensions and show you how to introduce a parallel dimension to your applications.

A "mini-talk" will also be given by Jason Bouffard about screen scraping with Goutte. The meeting is on December 6th at 7pm at the Strongbox West offices in Atlanta.

In his latest blog post, Jacob Santos takes a look at a common request PHP developers hit after a while - is it possible to multitask processes/actions in php?

The ability to run two or more commands in parallel is totally sexy, but the Web is a different playing field and it doesn’t make complete sense.

PHP loses control, once the output is sent and the connection is closed. Multithreading would probably make sense in streaming, but PHP already handles that for you where it makes sense for the function. Furthermore, mulithreading has its purpose in applications that continue to run and not something that closes and cleans up everything after the last command is issued.

He continues talking more about what multitasking is, a more real life example, the goods, the bads, and some of the issues that can come along with it. Finally, he suggests a feature to be added to the core of PHP - an "internal multitasking mechanism" to help aid these kinds of processes.

In his latest blog post, Jacob Santos takes a look at a common request PHP developers hit after a while - is it possible to multitask processes/actions in php?

The ability to run two or more commands in parallel is totally sexy, but the Web is a different playing field and it doesn’t make complete sense.

PHP loses control, once the output is sent and the connection is closed. Multithreading would probably make sense in streaming, but PHP already handles that for you where it makes sense for the function. Furthermore, mulithreading has its purpose in applications that continue to run and not something that closes and cleans up everything after the last command is issued.

He continues talking more about what multitasking is, a more real life example, the goods, the bads, and some of the issues that can come along with it. Finally, he suggests a feature to be added to the core of PHP - an "internal multitasking mechanism" to help aid these kinds of processes.