The document discusses strategies for migrating a legacy PHP application to Symfony 2. It covers rewriting vs migrating, code organization, routing, database migration, authentication/sessions, and templating considerations. Key points include setting up two front controllers, using events to handle legacy requests, importing database metadata, generating entities, and registering session bags to share authentication data between the applications during the migration. Rewriting carries risks of underestimating work, while migrating allows a gradual transition and fading out of old code over time.

1. From *
to Symfony 2
* Sf1, Zf1, PHP plain, …
Manuel “Kea” Baldassarri

2. If anything can go
wrong, it will
Capt. Edward A. Murphy

3. Agenda
•rewrite vs. migration
•code organization
•routing
•database
•authentication aka session

4. Program complexity grows until it
exceeds the capability of the
programmer who must maintain it.
Murphy's laws

5. Rewrite
vs
migration

6. Rewrite (theory)
Features
0
30
60
90
120
t0 t1 t2 t3 t4 t5
Old site New site

7. If anything can go wrong,
it will
Murphy's laws

8. Rewrite (real)
0
30
60
90
120
t0 t1 t2 t3 t4 t5
Old site New site real

9. Rewrite
Estimations are wrong, the legacy
code is worse than your wildest
imagination, the customer wants
new features, you have to
maintain the current site and
develop the new code base, you
code fast, port the same feature
from the old site to the new one,
import db, deploy, switch…

11. Migration
Features
0
30
60
90
120
t0 t1 t2 t3 t4 t5
Old tech New tech Total

12. Rewrite: practice
Only two steps if you decide to
rewrite your paper

13. • Foto con mac e blocco

14. Rewrite
$ rm -Rf project
$ symfony new project

16. Pre migration
PHP > 5.3

17. Symfony 1.5
LExpress/symfony1

18. PHPCompatibility
$ phpcs --standard=PHPCompatibility
--runtime-set testVersion 5.6

19. Code structure:
as you wish

20. Routing:
multiple entry
point

22. Catch’em all route
/**
* @Route("/{filename}.php")
*/
public function catchEmAllAction($filename)
{
ob_start();
include $filename.”.php”;
$content = ob_get_clean();
$this->doSomeHeadersStuff(headers_list());
return new Response($content);
}

23. Routing:
2 front controllers

24. Two front controllers
/path/to/legacy/public/index.php
/path/to/sf2/web/app.php

25. Easy way
REQUEST
WEB SERVER
FRONT CTRL 1 FRONT CTRL 2

26. Subdomain
http://www.mysite.com
http://new.mysite.com
OLD
NEW

27. Url prefix
http://www.mysite.com/
http://www.mysite.com/new/
OLD
NEW

28. Sf2 proxy
REQUEST
WEB SERVER
FRONT CTRL 2 FRONT CTRL 1

29. Event listener
legacy.kernel.listener:
class: AppBundleLegacyBridgeKernelListener
tags:
-
name: kernel.event_listener
event: kernel.exception
method: onKernelException

30. NotFoundHttpException
public function onKernelException($event)
{
$exception = $event->getException();
if ($exception instanceof
NotFoundHttpException) {
ob_start();
include "/path/to/old/index.php";
$content = ob_get_clean();
$this->doSomeHeadersStuff(headers_list());
$event->setResponse(new Response($content));
}
}

31. Database

32. Database
• Cleanup
• Import metadata/structure
• Create entity
• [Add annotation]

33. Metadata
$ php app/console
doctrine:mapping:import
--force AppBundle xml

34. Entities
$ php app/console
doctrine:generate:entities AppBundle

35. Annotation
$ php app/console
doctrine:mapping:convert annotation ./src

36. Annotation
/**
* IngredientTranslation
*
* @ORMTable(name=“ingredient_translation",
* indexes={
* @ORMIndex(name=“IDX_C1A8BF6BF396750”,
* columns={“id"})
* })
* @ORMEntity
*/
class IngredientTranslation
{
…
}

37. Entities
class Wow
{
/**
* @ORMColumn(name="p0", type="integer")
* @ORMId
*/
private $p0;
/**
* @ORMColumn(name="p1", type="string", …)
*/
private $p1;
…
}

38. Entities
class Wow
{
/**
* @ORMColumn(name="p0", type="integer")
* @ORMId
*/
private $id;
/**
* @ORMColumn(name="p1", type="string", …)
*/
private $title;
…
}

39. Authentication
aka
Session

41. Login in Sf2 app
Add layer to read Sf2 session
Forge a compatible $_SESSION
or

42. Login in “Old” app
Use preAuthentication

43. SessionBagInterface
MetadataBag
FlashBag
AutoExpireFlashBag
AttributeBag
NamespacedAttributeBag

44. $_SESSION
(old app logged in)
[
'App' =>
[
'user_id' => 10,
‘username' => 'kea'
]
]

45. $_SESSION
(anonym)
[
'_sf2_attributes' => [ ]
'_sf2_flashes' => [ ]
'_sf2_meta' => [ ... ]
]

46. $_SESSION
(logged in)
[
'_sf2_attributes' =>
[
'_security_application' =>
<serialised token>
…
]
…
]

47. Register bag
onKernelRequest
$bag = new NamespacedAttributeBag('App');
$bag->setName('App');
$session->registerBag($bag);

48. SimplePreAuthenticator
public function createToken(
Request $request, $providerKey)
{
$session = $request->getSession();
$bag = $session->getBag('App');
if (!$bag->has("user_id") ||
!$bag->has("username")) {
throw new BadCredentialsException(‘!');
}
…
}

49. SimplePreAuthenticator
public function createToken(
Request $request, $providerKey)
{
…
return new PreAuthenticatedToken(
'anon.',
[
"id" => $bag->has("user_id"),
"username" => $bag->has("username")
],
$providerKey
);
}

50. SimplePreAuthenticator
public function authenticateToken(
TokenInterface $token,
UserProviderInterface $userProvider,
$providerKey)
{
$credentials = $token->getCredentials();
$user = $this
->userProvider
->loadUserByIdAndUsername(
$credentials[“id"],
$credentials[“username"]
);
…
}

51. The bundle
TheodoEvolutionSessionBundle

52. Alternative way
Single Sign On

53. Templating

54. Templating

55. Rewrite pros
•green field
•no old code to manage

56. Rewrite cons
•data import
•time to market
•two sites to maintain

57. Migration pros
•time to market
•gradual learning
•fade out of old code
•no data migration

58. Migration cons
•spaghetti code for long
time
•learn how to pair two
technologies

59. Thank You

60. References and credits
https://github.com/wimg/PHPCompatibility
https://github.com/LExpress/symfony1
http://symfony.com/doc/current/cookbook/doctrine/
reverse_engineering.html
https://github.com/theodo/
TheodoEvolutionSessionBundle
https://github.com/marfillaster/
ButterweedSF1EmbedderBundle
https://www.flickr.com/photos/clairity/1267539354
https://www.flickr.com/photos/usfwshq/6777513684