Microservices are a huge trend, and microframeworks are perfect for them: put together just a few files, write some code, and your done! But Symfony is a big framework, right? Wrong! Symfony can be as small as a single file! In this talk, we'll learn how to use Symfony as a micro-framework for your next project. Your app will stay small and clear, but without needing to give up the features or third-party bundles that you love. And if the project grows, it can evolve naturally into a full Symfony project. So yes, Symfony can also be a microframework. Tell the world!

1. Symfony:
Your Next Microframework
by your friend:
Ryan Weaver
@weaverryan
by your friend:
Ryan Weaver
@weaverryan

2. KnpUniversity.com
github.com/weaverryan
Who is this guy?
> Lead for the Symfony documentation
> KnpLabs US - Symfony Consulting,
training & general Kumbaya
> Writer for KnpUniversity.com Tutorials
> Husband of the much more
talented @leannapelham

3. Thinking about 2
Problems
@weaverryan

4. Problem 1:
Symfony Sucks
@weaverryan

5. @weaverryan

6. @weaverryan

7. @weaverryan

8. @weaverryan

9. Symfony
is too hard
@weaverryan

10. The Symfony Framework
is too hard
@weaverryan
The components are not usually the
problem

11. Why?
@weaverryan

12. Route
Controller
Response
@weaverryan
WTF?
Useful Objects

13. 1) Common tasks require
too much code
@weaverryan

14. 2) Symfony is too big
@weaverryan

15. Too many files
==
A Perceived Complexity
@weaverryan

16. @weaverryan
~ 25 files
~ 10 directories
for Hello World

17. Problem 2:
Is my project
macro or micro?
@weaverryan

18. Macro => Use Symfony
@weaverryan

19. Micro => Use Silex
@weaverryan

20. The fact we have this
option is incredible
but…
@weaverryan

21. Silex has a slightly
different tech stack
@weaverryan

22. Silex doesn’t have bundles
@weaverryan

23. Silex can’t evolve to a full
stack Symfony App
@weaverryan

24. What if we just made
Symfony smaller?
@weaverryan

26. 6 files
62 lines of code

27. <?php
use SymfonyComponentHttpKernelKernel;
use SymfonyComponentConfigLoaderLoaderInterface;
class AppKernel extends Kernel
{
public function registerBundles()
{
return array(
new SymfonyBundleFrameworkBundleFrameworkBundle(),
new SymfonyBundleTwigBundleTwigBundle(),
);
}
public function registerContainerConfiguration($loader)
{
$loader->load(
__DIR__.'/config/config_'.$this->getEnvironment().'.yml'
);
}
}

28. How small can we go?
@weaverryan

29. What is a Symfony
Application?
@weaverryan

30. What is a Symfony App?
@weaverryan
1.A set of bundles
2.A container of services
3.Routes

31. Let’s create a new
Symfony project
from nothing
@weaverryan

32. {
"require": {
"symfony/symfony": "^2.8"
}
}
@weaverryan
composer.json

33. <?php
use SymfonyComponentConfigLoaderLoaderInterface;
use SymfonyComponentHttpKernelKernel;
require __DIR__.'/vendor/autoload.php';
class AppKernel extends Kernel
{
public function registerBundles()
{
}
public function registerContainerConfiguration($loader)
{
}
}
index.php

34. <?php
use SymfonyBundleFrameworkBundleKernelMicroKernelTrait;
use SymfonyComponentDependencyInjectionContainerBuilder;
use SymfonyComponentRoutingRouteCollectionBuilder;
// ...
class AppKernel extends Kernel
{
use MicroKernelTrait;
public function registerBundles()
{
}
protected function configureRoutes(RouteCollectionBuilder $routes)
{
}
protected function configureContainer(ContainerBuilder $c, $loader)
{
}
}
index.php
1) A set of bundles
2) Routes
3) A container of services

35. public function registerBundles()
{
return array(
new SymfonyBundleFrameworkBundleFrameworkBundle()
);
}
AppKernel

36. protected function configureContainer(ContainerBuilder $c, $loader)
{
$c->loadFromExtension('framework', array(
'secret' => 'S0ME_SECRET',
));
}
AppKernel
// config.yml
framework:
secret: S0ME_SECRET

37. protected function configureRoutes(RouteCollectionBuilder $routes)
{
$routes->add('/random/{limit}', 'kernel:randomAction');
}
AppKernel
New in 2.8!
service:methodName
(Symfony’s controller as a service syntax)

38. public function randomAction($limit)
{
return new JsonResponse(array(
'number' => rand(0, $limit)
));
}
AppKernel

39. <?php
// ...
require __DIR__.'/vendor/autoload.php';
class AppKernel extends Kernel
{
// ...
}
$kernel = new AppKernel('dev', true);
$request = Request::createFromGlobals();
$response = $kernel->handle($request);
$response->send();
$kernel->terminate($request, $response);
index.php

40. How many files?
@weaverryan
How many lines of code?

41. 2 files
52 lines of code

42. This is a full stack
framework
@weaverryan

43. @weaverryan
1. Service Container
2. Routing
3. Events
4. ESI & Sub-Requests
5. Compatible with 3rd party bundles

44. Fast as Hell
@weaverryan

45. The goal is not to create
single-file apps
@weaverryan

46. Clarity & Control
@weaverryan

47. Building a
Realistic App
@weaverryan
github.com/weaverryan/docs-micro_kernel

48. Requirements:
@weaverryan
1. Add some organization
2. Load annotation routes
3. Web Debug Toolbar + Profiler
4. Twig

49. Reorganize
class AppKernel extends Kernel
{
}
// web/index.php
$kernel = new AppKernel('dev', true);
$request = Request::createFromGlobals();
$response = $kernel->handle($request);
$response->send();

50. public function registerBundles()
{
$bundles = array(
new FrameworkBundle(),
new TwigBundle(),
new SensioFrameworkExtraBundle()
);
if ($this->getEnvironment() == 'dev') {
$bundles[] = new WebProfilerBundle();
}
return $bundles;
}
app/AppKernel.php

51. protected function configureContainer(ContainerBuilder $c, $loader)
{
$loader->load(__DIR__.'/config/config.yml');
if (isset($this->bundles['WebProfilerBundle'])) {
$c->loadFromExtension('web_profiler', array(
'toolbar' => true,
'intercept_redirects' => false,
));
}
}
app/AppKernel.php
@weaverryan

52. app/config/config.yml
framework:
secret: S0ME_SECRET
templating:
engines: ['twig']
profiler: { only_exceptions: false }
@weaverryan

53. protected function configureContainer(ContainerBuilder $c, $loader)
{
$loader->load(__DIR__.'/config/config.yml');
if (isset($this->bundles['WebProfilerBundle'])) {
$c->loadFromExtension('web_profiler', array(
'toolbar' => true,
'intercept_redirects' => false,
));
}
}
app/AppKernel.php
@weaverryan
Goodbye config_dev.yml

54. protected function configureRoutes(RouteCollectionBuilder $routes)
{
if (isset($this->bundles['WebProfilerBundle'])) {
$routes->import(
'@WebProfilerBundle/Resources/config/routing/wdt.xml',
'_wdt'
);
$routes->import(
'@WebProfilerBundle/Resources/config/routing/profiler.xml',
'/_profiler'
);
}
$routes->import(__DIR__.'/../src/App/Controller/', '/', 'annotation')
}
app/AppKernel.php
Goodbye routing_dev.yml

56. Clarity & Control
@weaverryan

57. @weaverryan
protected function configureContainer(ContainerBuilder $c, $loader)
{
$loader->load(__DIR__ . '/config/config.yml');
$c->setParameter('secret', getenv('SECRET'));
$c->loadFromExtension('doctrine', [
'dbal' => [
'driver' => 'pdo_mysql',
'host' => getenv('DATABASE_HOST'),
'user' => getenv('DATABASE_USER'),
'password' => getenv('DATABASE_PASS'),
]
]);
// ...
}
Environment Variables

58. @weaverryan
protected function configureContainer(ContainerBuilder $c, $loader)
{
$loader->load(__DIR__.'/config/config.yml');
if (in_array($this->getEnvironment(), ['dev', 'test'])) {
$c->loadFromExtension('framework', [
'profiler' => ['only_exceptions' => false]
]);
}
// ...
}
Environment Control

59. @weaverryan
Build Services
protected function configureContainer(ContainerBuilder $c, $loader)
{
// ...
$c->register('santa.controller', SantaController::class)
->setAutowired(true);
}

60. @weaverryan
Build Routes
protected function configureRoutes(RouteCollectionBuilder $routes)
{
// ...
$routes->add('/santa', 'AppBundle:Santa:northPole');
$routes->add(‘/naughty-list/{page}’, 'AppBundle:Santa:list')
->setRequirement('list', 'd+')
->setDefault('page', 1);
}

61. @weaverryan
Bundless
Applications?

63. @weaverryan
Wait, what does a
bundle even give me?

64. A bundle gives you:
@weaverryan
1. Services
2. A resource root (e.g. path to load templates)
3. Magic functionality (e.g. commands)
4. Shortcuts
(_controller, AppBundle:User)

65. @weaverryan
1) Services
protected function configureContainer(ContainerBuilder $c, $loader)
{
// ...
$c->register('santa.controller', SantaController::class)
->setAutowired(true);
}

66. @weaverryan
2) Resource Root

67. 2) Resource Root
protected function configureContainer(ContainerBuilder $c, $loader)
{
// ...
$c->loadFromExtension('twig', [
'paths' => [__DIR__.'/Resources/views' => 'north_pole']
]);
}
public function randomAction($limit)
{
$number = rand(0, $limit);
return $this->render(‘@north_pole/micro/random.html.twig’, [
'number' => $number
]);
}

68. @weaverryan
3) Magic Functionality
1. Register commands as services
2. Configure Doctrine mappings to load your
Entity directory

69. @weaverryan
4) Shortcuts
santa:
controller: AppBundle:Santa:xmas
controller: AppBundleControllerSantaController::xmasAction
$em->getRepository('AppBundle:App');
$em->getRepository('AppBundleEntityApp');

70. @weaverryan
One New Trick
protected function configureRoutes(RouteCollectionBuilder $routes)
{
$routes->import(__DIR__.’@AppBundle/Controller/‘, '/', 'annotation')
}
protected function configureRoutes(RouteCollectionBuilder $routes)
{
$routes->import(__DIR__.'/../src/App/Controller/', '/', 'annotation')
}

71. Multiple Kernels?
@weaverryan

72. Multiple kernels, why?
@weaverryan
1. micro service architecture in monolithic
repository
2. performance (less routes, services &
listeners)

73. Multiple kernels was
always possible
@weaverryan

74. Now they’re obvious
@weaverryan

75. // app/ApiKernel.php
class ApiKernel extends Kernel
{
use MicroKernelTrait;
public function registerBundles()
{
$bundles = array(
new FrameworkBundle(),
new SensioFrameworkExtraBundle()
);
return $bundles;
}
}
No TwigBundle

76. class ApiKernel extends Kernel
{
// ...
protected function configureContainer($c, $loader)
{
$loader->load(__DIR__.'/config/config.yml');
$loader->load(__DIR__.'/config/api.yml');
}
}
Use PHP logic to load share
config, and custom config

77. class ApiKernel extends Kernel
{
// ...
protected function configureRoutes($routes)
{
$routes->import(
__DIR__.'/../src/Api/Controller/',
'/api',
'annotation'
);
}
public function getCacheDir()
{
return __DIR__.’/../var/cache/api/'
.$this->getEnvironment();
}
}
Load different routes
cacheDir ~= the cache key

78. Boot the correct kernel
however you want
@weaverryan

79. // web/index.php
use SymfonyComponentHttpFoundationRequest;
require __DIR__.'/../app/autoload.php';
$request = Request::createFromGlobals();
if (strpos($request->getPathInfo(), '/api') === 0) {
require __DIR__.'/../app/ApiKernel.php';
$kernel = new ApiKernel('dev', true);
} else {
require __DIR__.'/../app/WebKernel.php';
$kernel = new WebKernel('dev', true);
}
$response = $kernel->handle($request);
$response->send();

81. But how does it work?
@weaverryan

82. There is one person
who *hates* the name
MicroKernelTrait
@weaverryan

83. @weaverryan

84. @weaverryan

85. trait MicroKernelTrait
{
abstract protected function configureRoutes(RouteCollectionBuilder $routes);
abstract protected function configureContainer(ContainerBuilder $c, $loader);
public function registerContainerConfiguration($loader)
{
$loader->load(function ($container) use ($loader) {
$container->loadFromExtension('framework', array(
'router' => array(
'resource' => 'kernel:loadRoutes',
'type' => 'service',
),
));
$this->configureContainer($container, $loader);
});
}
public function loadRoutes(LoaderInterface $loader)
{
$routes = new RouteCollectionBuilder($loader);
$this->configureRoutes($routes);
return $routes->build();
}
}
Closure Loader
New service route loader

86. So what now?
@weaverryan

87. I have a big project…
@weaverryan
Use it for clarity

88. I’m teaching
@weaverryan
Show it for simplicity

89. I have a small app
@weaverryan
Show it for power

90. @weaverryan
PHP & Symfony Video Tutorials
KnpUniversity.com
Thank You!