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

Talk presented at PHP UK Conference 2017 in London, England.

Transcript

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

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2. David Zuelke
   

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4. dz@heroku.com
   

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5. @dzuelke
   

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6. CGI
   

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7. NCSA, 1993
   

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9. RFC 3875, 1997-2004
   

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

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14. 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
    

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15. slow
    

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16. (but simple)
    

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

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18. 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, …
    

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19. PHP's SAPIs

    & EXECUTION MODEL
    

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20. a SAPI is the "gateway" to the PHP engine
    

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21. marshals input and output from and to the interface
    

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22. 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
    

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23. PHP was built for web scripting, for CGI
    

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24. execution model modeled around statelessness "blank slate"
    

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25. 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
    

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26. all of that on each CGI request
    

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27. NEIN NEIN
    NEIN NEIN
    DAS IST ZU
    LANGSAM
    

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28. mod_php
    

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29. embeds PHP into the Apache httpd process
    

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30. 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)
    

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31. but now PHP is in each httpd process
    

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32. even when serving static files
    

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33. 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)
    

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34. so... what do we do?
    

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35. ¯\_(ϑ)_/¯
    

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36. "let's just use Nginx!"
    

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37. FastCGI
    

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38. protocol similar to CGI, but over a socket
    

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39. persistent server process
    

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40. old fcgi SAPI: web server manages FastCGI child processes
    

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41. newer FPM: PHP manages its own child processes' lifecycle
    

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42. no overhead in web server for static content
    

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43. web server can use threading or whatever
    

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44. still re-executes from ~RINIT for each request
    

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45. still bootstraps Symfony/Laravel/… on each request
    

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46. RUBY & PYTHON
    

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47. Rack & WSGI
    

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48. 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
    

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49. 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, ...
    

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50. NATIVE PHP WEB SERVERS
    

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51. 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
    

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

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53. 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";
    

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54. 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();
    

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

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56. $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);
    });
    

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57. WHAT BECOMES POSSIBLE
    

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58. speeeeeeeeeed :)
    

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

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60. processing request data while it's still uploading
    

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61. handling Web Sockets in the same process
    

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

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63. WHAT BECOMES IMPOSSIBLE
    

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64. native session handling
    

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65. ignoring memory leaks
    

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66. MAYBE, IN A BRIGHT FUTURE...
    

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

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68. a universe of useful middlewares :)
    

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69. competition between different native web servers :)
    

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

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

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72. 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
    

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73. The End
    

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74. THANK YOU FOR LISTENING!
    Questions? Ask me: @dzuelke & dz@heroku.com
    

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