Your next Web server will be written in... PHP

YOUR NEXT WEB SERVER WILL BE WRITTEN IN... PHP MIGHT
PHP UK Conference 2017 London, England

David Zuelke

[email protected]

@dzuelke

NCSA, 1993

RFC 3875, 1997-2004

/cgi-bin/counter.pl?site=8712

HOW CGI WORKS 1. Web server parses request from client
2. Web server sets request info into environment  (PATH_INFO, REQUEST_METHOD, HTTP_ACCEPT, …) 3. Web server executes CGI script 4. CGI script echos status, headers, and body 5. Web server returns response to client

(but simple)

#!/bin/bash cat <<EOF Content-Type: text/html <html> <head> <title>Hello World</title> </head>
<body> <h1>Hello World</h1> <p>Your browser is ${HTTP_USER_AGENT:-unknown}</p> <p>This page was served by $(hostname)</p> </body> </html> EOF

CGI VARIABLES (SEE $_SERVER) • Server info:  SERVER_SOFTWARE, SERVER_NAME, GATEWAY_INTERFACE
• Request info:  SERVER_PROTOCOL, SERVER_PORT, REQUEST_METHOD, PATH_INFO, PATH_TRANSLATED, QUERY_STRING, REMOTE_ADDR, CONTENT_TYPE, CONTENT_LENGTH, … • Request headers:  HTTP_HOST, HTTP_ACCEPT, HTTP_USER_AGENT, …

PHP's SAPIs  & EXECUTION MODEL

a SAPI is the "gateway" to the PHP engine

marshals input and output from and to the interface

PHP WEB SAPI (SIMPLIFIED) • populate $_SERVER and $_ENV •
parse QUERY_STRING into $_GET • " application/x-www-form-urlencoded into $_POST • " multipart/form-data into $_FILES • return header() data as headers, anything echo()d as content

PHP was built for web scripting, for CGI

execution model modeled around statelessness "blank slate"

PHP CGI EXECUTION LIFECYCLE  (SIMPLIFIED) 1. core init, load extensions
etc 2. MINIT for all modules (extension initialization etc) 3. SAPI ready for (one and only) request 4. RINIT for all modules (e.g. ext-session if session.auto_start) 5. script executes 6. RSHUTDOWN 7. engine cleanup (unset all variables and state) 8. MSHUTDOWN

all of that on each CGI request

NEIN NEIN NEIN NEIN DAS IST ZU LANGSAM

mod_php

embeds PHP into the Apache httpd process

mod_php EXECUTION LIFECYCLE  (SIMPLIFIED) 1. SAPI ready for (next) request
2. RINIT for all modules (e.g. ext-session if session.auto_start) 3. script executes 4. RSHUTDOWN 5. engine cleanup (unset all variables and state)

but now PHP is in each httpd process

even when serving static ﬁles

APACHE PROCESS MODELS • mpm_prefork creates worker processes  (each with
a PHP) • mpm_worker uses threads  (so you need ZTS, and stuff will generally crash a lot) • mpm_event uses an event loop  (best, but you can't embed something like PHP at all)

so... what do we do?

¯\_(ϑ)_/¯

"let's just use Nginx!"

FastCGI

protocol similar to CGI, but over a socket

persistent server process

old fcgi SAPI: web server manages FastCGI child processes

newer FPM: PHP manages its own child processes' lifecycle

no overhead in web server for static content

web server can use threading or whatever

still re-executes from ~RINIT for each request

still bootstraps Symfony/Laravel/… on each request

RUBY & PYTHON

Rack & WSGI

RUBY/RACK app = Proc.new do |env| ['200', {'Content-Type' => 'text/plain'},
['Hello World']] end def application(environ, start_response): start_response('200 OK', [('Content-Type', 'text/plain')]) yield 'Hello World\n' PYTHON/WSGI

THE RACK/WSGI STACKS 1. Web server:  Unicorn, Gunicorn, Puma, Tornado,
Phusion Passenger, mod_wsgi, ... 2. Middlewares:  Routing, authentication, ﬁltering, post-processing, ... 3. Application/framework:  Rails, Django, Sinatra, Flask, ...

NATIVE PHP WEB SERVERS

PHP IS NOW READY • PHP 7+ performance is amazing
• Almost all engine errors are catchable since PHP 7 • Signal handling without ticks in PHP 7.1 • Concurrency frameworks and event lib extensions

FRAMEWORKS FOR EVENT- DRIVEN NON-BLOCKING I/O • http://reactphp.org • https://icicle.io
• http://amphp.org

IT'S ALL A REACTOR echo "-- before run()\n"; Amp\run(function() {
Amp\repeat(function() { echo "tick\n"; }, $msInterval = 1000); Amp\once("Amp\stop", $msDelay = 5000); }); echo "-- after run()\n";

SIMPLE WEB SERVER, ReactPHP $app = function ($request, $response) {
$response->writeHead(200, array('Content-Type' => 'text/plain')); $response->end("Hello World\n"); }; $loop = React\EventLoop\Factory::create(); $socket = new React\Socket\Server($loop); $http = new React\Http\Server($socket, $loop); $http->on('request', $app); $socket->listen(1337); $loop->run();

https://github.com/M6Web/PhpProcessManagerBundle & https://github.com/php-pm/php-pm

$kernel = new AppKernel('prod', false); $reactHttp->on('request', function ($request, $response) use
($kernel) { $headers = $request->getHeaders(); if (in_array(strtoupper($request->getMethod()), ['POST','PUT','DELETE','PATCH']) && isset($headers['Content-Type']) && (0 === strpos($headers['Content-Type'], 'application/x-www-form-urlencoded')) ) parse_str($request->getBody(), $post); $sfRequest = new Symfony\Component\HttpFoundation\Request( $request->getQuery(), $post ?? [], array(), array(), $request->getFiles(), array(), $request->getBody() ); $sfRequest->setMethod($request->getMethod()); $sfRequest->headers->replace($headers); $sfRequest->server->set('REQUEST_URI', $request->getPath()); if (isset($headers['Host'])) $sfRequest->server->set('SERVER_NAME', explode(':', $headers['Host'])[0]); $sfResponse = $kernel->handle($sfRequest); $response->writeHead($sfResponse->getStatusCode(), $sfResponse->headers->all()); $response->end($sfResponse->getContent()); $kernel->terminate($request, $response); });

WHAT BECOMES POSSIBLE

speeeeeeeeeed :)

http://marcjschmidt.de/blog/2014/02/08/php-high-performance.html

processing request data while it's still uploading

handling Web Sockets in the same process

git clone project && cd project && composer install &&
php server.php

WHAT BECOMES IMPOSSIBLE

native session handling

ignoring memory leaks

MAYBE, IN A BRIGHT FUTURE...

PSR-7 (HTTP Message Interface) + PSR-15 (HTTP Middlewares) = ultimate
interop :)

a universe of useful middlewares :)

competition between different native web servers :)

"legacy" server that runs in FPM SAPI and translates a
request :)

"legacy" middleware that runs in new server and populates $_GET
and friends :)

READING MATERIAL • http://blog.kelunik.com/2015/09/20/getting-started-with-amp.html • http://blog.kelunik.com/2015/10/21/getting-started-with-aerys.html • http://blog.kelunik.com/2015/10/20/getting-started-with-aerys- websockets.html •
http://marcjschmidt.de/blog/2014/02/08/php-high-performance.html • http://marcjschmidt.de/blog/2016/04/16/php-high-performance-reactphp- jarves-symfony-follow-up.html • https://gnugat.github.io/2016/04/13/super-speed-sf-react-php.html

The End

THANK YOU FOR LISTENING! Questions? Ask me: @dzuelke & [email protected]

Your next Web server will be written in... PHP

Your next Web server will be written in... PHP

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