I Promise() to Teach You Asynchronous PHP

Asynchronous code sets JavaScript-powered projects apart from PHP. Thanks to some newer libraries, PHP can do the same tricks as Node on the server. This workshop will walk through the fundamentals of synchronous versus asynchronous execution. We will cover event loops in PHP and work through actual implementations of promises and co-routines. Finally, we will work through the steps required to convert an old-school synchronous application into a newfangled asynchronous beast!

Transcript

1. I Promise() to Teach you
   Asynchronous PHP
   Eric Mann - Tozny - php[tek] 2016
   

   View Slide

2. Terminology
   Imperative / Procedural
   Concurrent
   Parallel
   Concurrent Parallel
   

   View Slide

3. Project Setup
   

   View Slide

4. Copy the USB drive to your machine
   Install Vagrant/VirtualBox if you don’t have them
   Add the eisago Vagrant box: 

   vagrant box add ericmann/eisago eisago.box
   Start the Vagrant box and SSH into it
   Set up your IDE for the project
   

   View Slide

5. Part I: Imperative
   We’re building an importer - turn a collection of text
   files into an indexed MongoDB database
   Let’s work through the 5 TODOs in the application
   Now, let’s run it!
   

   View Slide

6. 10 minute break
   

   View Slide

7. Icicle/ReactPHP
   Write asynchronous (concurrent) code in PHP
   Support event loops natively (and stop blocking I/O)
   Use Promises in PHP to juggle multiple tasks at once
   Requires an event (and signaling) extension for PHP to
   work properly
   

   View Slide

8. Icicle/ReactPHP
   $promise = new Promise( function( $resolve, $reject ) {
   do_something_async()->then( $resolve );
   } );
   $promise
   ->then( function( $data ) {
   echo $data;
   } )->done ( function() {
   echo 'Done!';
   } );
   Loop\run();
   

   View Slide

9. Icicle/ReactPHP
   $promise1 = new Promise( function( $resolve, $reject ) {
   do_something_async()->then( $resolve );
   } );
   $promise2 = new Promise( function( $resolve, $reject ) {
   do_something_else_async()->then( $resolve );
   } );
   Icicle\Awaitable\all( [ $promise1, $promise2 ] )
   ->done( function() {
   echo 'Done!';
   }, function() {
   echo 'Error!';
   } );
   Loop\run();
   

   View Slide

10. Part II: Concurrent
    Let’s refactor for concurrency
    Again, there are 5 TODOs in the application
    Now, let’s run it!
    

    View Slide

11. 10 minute break
    

    View Slide

12. pthreads
    User-land multi-threading in PHP by way of an
    extension
    Provides threads, workers, and threaded objects
    All of your code – the server and the worker – are the
    same application
    Each component has its own scope
    

    View Slide

13. pthreads
    class WorkerThread extends Thread {
    private $workerId;
    public function __construct( $id ) {
    $this->workerId = $id;
    }
    public function run() {
    // Do some heavy processing
    }
    }
    

    View Slide

14. pthreads
    $workers = [];
    foreach ( range( 0, 5 ) as $id ) {
    $worker = new WorkerThread( $id );
    $workers[] = $worker;
    $worker->start(); // Now they'll each run independently
    }
    foreach ( range( 0, 5 ) as $id ) {

    // Force the threads to rejoin the main process synchronously
    $workers[ $id ]->join();
    }
    

    View Slide

15. Part III: Concurrent Parallel
    Let’s refactor for parallelism (threading)
    Yet again, there are 5 TODOs in the application

    They’re in 2 different files, though …
    Now, let’s run it!
    

    View Slide

16. Questions?
    

    View Slide

17. I Promise() to Teach you
    Asynchronous PHP
    Eric Mann - Tozny - php[tek] 2016
    

    View Slide