This document contains the slides from a presentation on building asynchronous bots in PHP using AMPHP. The presentation discusses asynchronous I/O, event loops, and using AMPHP to build bots that can interact with Twitter's APIs asynchronously. It provides code examples of making asynchronous HTTP requests and processing a Twitter stream using an event loop. The presentation recommends AMPHP as a complete asynchronous framework for PHP that can be used for both event loop and fork/join parallelism in building high performance asynchronous applications.

1. @adam_englander
Build A Bot Workshop:
Async Primer
Adam Englander
iovation

2. PHP[TEK] 2017
Wifi:
Sheraton Meeting
Network
Pass: php2017
Twitter:
#phptek
Rate the talks
https://joind.in/event/phptek-2017

3. Thanks to our
Sponsors!

4. @adam_englander
What You Will Need
• PHP 5.6, 7.0, or 7.1 (Examples will be 7.1)
• intl extension
• Twitter account
• Twitter Developer App: https://apps.twitter.com
• OAuth Credentials: https://dev.twitter.com/oauth/
overview/application-owner-access-tokens

5. @adam_englander
What We Will Discuss
• Concurrent Programming
• Asynchronous I/O
• AMPHP Asynchronous Framework for PHP

6. @adam_englander
What We Will Do
1. We will use an asynchronous HTTP client to
execute a Twitter REST API command.
2. We will use an asynchronous HTTP client to
process a continuous stream via the Twitter
User Stream API.
3. We will leverage both of the above to listen to a
topic and automatically respond to updates.

7. @adam_englander
Concurrent Programming
• Forking and Threading
• Asynchronous I/O
• Fork/Join
• Event Loop
Strategies Methodologies

8. @adam_englander
Forking and Threading
• Available in PHP core since PHP 4.1
• Requires the use of shared memory
• Requires code to be written for management of
forks/threads
• Creates separate copies of code for each
thread/fork

9. @adam_englander
Asynchronous I/O
• Frees up the current process while I/O is
performed
• Executes code based on I/O events
• No copying of code for separate process

10. @adam_englander
Asynchronous I/O Libraries
• Streams via stream_select and socket_select
• eio — libeio
• ev — libev
• libevent — libevent
• event — libevent

11. @adam_englander
Fork/Thread vs Async I/O
• Compute heavy
• Process isolation
• Non-Async library
• I/O processes
• Process/memory
optimization
Fork/Thread Async I/O

12. @adam_englander
Fork/Join Parallelism
S TA RT
P R O C E S S 1
P R O C E S S 2
P R O C E S S 3
E N DF O R K J O I N

13. Fork/Join Example
$dispatcher = new AmpThreadDispatcher();
$a = $dispatcher->call('slowProcess1');
$b = $dispatcher->call('slowProcess2');
$c = $dispatcher->call('slowProcess3');
$comboPromise = Ampall([$a, $b, $c]);
list($a, $b, $c) = Ampwait($comboPromise);

14. @adam_englander
Event Loop Parallelism
P R O C E S S
Q U E U E
I T E M
Q U E U E
I T E M
I N
Q U E U E ?
X
Yes
No
A S Y N C
P R O C E S S
A S Y N C
P R O C E S S
A S Y N C
P R O C E S S
A S Y N C
P R O C E S S

15. Event Loop Example
<?php
# Build objects to handle asynchronous interaction
$loop = ReactEventLoopFactory::create();
$dnsFactory = new ReactDnsResolverFactory();
$dns = $dnsFactory->createCached('8.8.8.8', $loop);
$factory = new ReactHttpClientFactory();
$client = $factory->create($loop, $dns);
$resp = array();
# Create callback for handling response
$responseHandler = function ($response) use ($resp) {
$response->on( 'data', function ($data) use ($resp) {
$resp[] = $data;
});
};
# Queue up requests to send
$request = $client->request('GET', 'http://www.timeapi.org/utc/now');
$request->on('response', $responseHandler);
$request->end();
$request = $client->request('GET', 'http://www.timeapi.org/utc/now');
$request->on('response', $responseHandler);
$request->end();
# Run the loop
$loop->run();

16. @adam_englander
Fork/Join vs Event Loop
• Enhance existing
synchronous apps
• Promises
• Hack/HHVM
• Non-HTTP apps
• Full async apps
• High volume apps
Fork/Join Event Loop

17. Callbacks vs. Generators
$stream = yield $apiClient->request($request);
while (null !== $message = yield $stream->read()) {
print($message[‘user’][‘screen_name’].": “.$message[‘text']);
}
Callback
Generator
Aerysrouter()
->get("/", function (AerysRequest $req, AerysResponse $resp) {
$resp->end("<h1>Hello World!</h1>");
})
->head("/", function (AerysRequest $req, AerysResponse $resp) {
$resp->end("<h1>Hello Head!</h1>");
});

18. @adam_englander
AMPHP
Asynchronous Framework for PHP

19. @adam_englander
Complete Modern Framework
• Modular framework segmented into logical parts
• Supersedes icicle.io
• Drivers for common storage engines
• Can be used for event loop and fork/join
• Can use threads or async i/o

20. @adam_englander
Code Time!

21. @adam_englander
• http://amphp.org/
• #amphp on Freenode IRC
• http://blog.kelunik.com/
• https://dev.twitter.com/
• https://github.com/PeeHaa/AsyncTwitter
• https://github.com/aenglander/amp-twitter-bot
Resources

22. @adam_englander
More From Me
• @adam_englander on Twitter
• @aenglander on Freenode
• adam.englander@iovation.com

23. @adam_englander
Please Rate Me
https://joind.in/talk/d5786