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Branch fix #6745

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Jul 10, 2016
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afab48c
[] changes in the first four ch of the book
paxyknox Feb 10, 2016
ef5c0e6
made some new changes, corrected mistakes, undo some foolish deletions
paxyknox Feb 12, 2016
a1a505b
colon corrections
paxyknox Feb 12, 2016
b378933
typo fix in hyperlink
paxyknox Feb 12, 2016
a9cdc3c
typo fix in hyperlink
paxyknox Feb 12, 2016
d82f05c
changes according to comments after PR + some other typos
paxyknox Mar 18, 2016
a955b5c
[WIP] Reading through the changes
weaverryan Jul 10, 2016
2593382
[WIP] More changes
weaverryan Jul 10, 2016
c43f58b
[WIP] Removing multiple formats - it makes no sense here
weaverryan Jul 10, 2016
d073dcc
[WIP] More changes
weaverryan Jul 10, 2016
0410e62
[WIP] More changes
weaverryan Jul 10, 2016
e6f52a0
Final changes
weaverryan Jul 10, 2016
d271df7
Fixing typo
weaverryan Jul 10, 2016
a32adca
Replacing missing link
weaverryan Jul 10, 2016
6475bff
Removing old :term: stuff
weaverryan Jul 10, 2016
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190 changes: 110 additions & 80 deletions book/from_flat_php_to_symfony2.rst
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Original file line number Diff line number Diff line change
@@ -1,14 +1,18 @@
.. index::
single: Symfony versus Flat PHP

.. _symfony2-versus-flat-php:

Symfony versus Flat PHP
=======================

**Why is Symfony better than just opening up a file and writing flat PHP?**

If you've never used a PHP framework, aren't familiar with the MVC philosophy,
or just wonder what all the *hype* is around Symfony, this chapter is for
you. Instead of *telling* you that Symfony allows you to develop faster and
better software than with flat PHP, you'll see for yourself.
If you've never used a PHP framework, aren't familiar with the
`Model-View-Controller`_ (MVC) philosophy, or just wonder what all the *hype*
is around Symfony, this chapter is for you. Instead of *telling* you that
Symfony allows you to develop faster and better software than with flat PHP,
you'll see for yourself.

In this chapter, you'll write a simple application in flat PHP, and then
refactor it to be more organized. You'll travel through time, seeing the
Expand Down Expand Up @@ -98,11 +102,12 @@ the code that prepares the HTML "presentation"::
require 'templates/list.php';


The HTML code is now stored in a separate file (``templates/list.php``), which
The HTML code is now stored in a separate file ``templates/list.php``, which
is primarily an HTML file that uses a template-like PHP syntax:

.. code-block:: html+php

<!-- templates/list.php -->
<!DOCTYPE html>
<html>
<head>
Expand Down Expand Up @@ -179,6 +184,7 @@ of the application are isolated in a new file called ``model.php``::

The controller (``index.php``) is now very simple::

// index.php
require_once 'model.php';

$posts = get_all_posts();
Expand All @@ -197,7 +203,7 @@ offering various advantages and the opportunity to reuse almost everything
on different pages.

The only part of the code that *can't* be reused is the page layout. Fix
that by creating a new ``layout.php`` file:
that by creating a new ``templates/layout.php`` file:

.. code-block:: html+php

Expand All @@ -212,11 +218,12 @@ that by creating a new ``layout.php`` file:
</body>
</html>

The template (``templates/list.php``) can now be simplified to "extend"
the layout:
The template ``templates/list.php`` can now be simplified to "extend"
the ``templates/layout.php``:

.. code-block:: html+php

<!-- templates/list.php -->
<?php $title = 'List of Posts' ?>

<?php ob_start() ?>
Expand All @@ -237,8 +244,9 @@ the layout:
You now have a setup that will allow you to reuse the layout.
Unfortunately, to accomplish this, you're forced to use a few ugly
PHP functions (``ob_start()``, ``ob_get_clean()``) in the template. Symfony
uses a Templating component that allows this to be accomplished cleanly
and easily. You'll see it in action shortly.
uses a :doc:`Templating </components/templating/introduction>` component
that allows this to be accomplished cleanly and easily. You'll see it in
action shortly.

Adding a Blog "show" Page
-------------------------
Expand Down Expand Up @@ -270,6 +278,7 @@ an individual blog result based on a given id::
Next, create a new file called ``show.php`` - the controller for this new
page::

// show.php
require_once 'model.php';

$post = get_post_by_id($_GET['id']);
Expand All @@ -281,6 +290,7 @@ the individual blog post:

.. code-block:: html+php

<!-- templates/show.php -->
<?php $title = $post['title'] ?>

<?php ob_start() ?>
Expand Down Expand Up @@ -327,9 +337,9 @@ application change slightly, but start to become more flexible:
/index.php/show => Blog post show page (index.php executed)

.. tip::
The ``index.php`` portion of the URI can be removed if using Apache
rewrite rules (or equivalent). In that case, the resulting URI of the
blog show page would be simply ``/show``.

By using rewrite rules in your :doc:`web server configuration </cookbook/configuration/web_server_configuration>`,
the ``index.php`` won't be needed and you will have beautiful, clean URLs (e.g. ``/show``).

When using a front controller, a single PHP file (``index.php`` in this case)
renders *every* request. For the blog post show page, ``/index.php/show`` will
Expand Down Expand Up @@ -364,8 +374,9 @@ on the requested URI::
}

For organization, both controllers (formerly ``index.php`` and ``show.php``)
are now PHP functions and each has been moved into a separate file, ``controllers.php``::
are now PHP functions and each has been moved into a separate file named ``controllers.php``::

// controllers.php
function list_action()
{
$posts = get_all_posts();
Expand All @@ -382,7 +393,11 @@ As a front controller, ``index.php`` has taken on an entirely new role, one
that includes loading the core libraries and routing the application so that
one of the two controllers (the ``list_action()`` and ``show_action()``
functions) is called. In reality, the front controller is beginning to look and
act a lot like Symfony's mechanism for handling and routing requests.
act a lot like how Symfony handles and routes requests.

But but careful not to confuse the terms *front controller* and *controller*. Your
app will usually have just *one* front controller, which boots your code. You will
have *many* controller functions: one for each page.

.. tip::

Expand All @@ -393,8 +408,8 @@ act a lot like Symfony's mechanism for handling and routing requests.

By now, the application has evolved from a single PHP file into a structure
that is organized and allows for code reuse. You should be happier, but far
from satisfied. For example, the "routing" system is fickle, and wouldn't
recognize that the list page (``/index.php``) should be accessible also via ``/``
from satisfied. For example, the routing system is fickle, and wouldn't
recognize that the list page - ``/index.php`` - should be accessible also via ``/``
(if Apache rewrite rules were added). Also, instead of developing the blog,
a lot of time is being spent working on the "architecture" of the code (e.g.
routing, calling controllers, templates, etc.). More time will need to be
Expand All @@ -407,7 +422,7 @@ Add a Touch of Symfony
~~~~~~~~~~~~~~~~~~~~~~

Symfony to the rescue. Before actually using Symfony, you need to download
it. This can be done by using Composer, which takes care of downloading the
it. This can be done by using `Composer`_, which takes care of downloading the
correct version and all its dependencies and provides an autoloader. An
autoloader is a tool that makes it possible to start using PHP classes
without explicitly including the file containing the class.
Expand All @@ -427,7 +442,7 @@ content:
}

Next, `download Composer`_ and then run the following command, which will download Symfony
into a vendor/ directory:
into a ``vendor/`` directory:

.. code-block:: bash

Expand Down Expand Up @@ -501,7 +516,8 @@ incidentally, acts quite a bit like the Symfony templating engine::

By bringing in a small part of Symfony, the application is more flexible and
reliable. The ``Request`` provides a dependable way to access information
about the HTTP request. Specifically, the ``getPathInfo()`` method returns
about the HTTP request. Specifically, the
:method:`Symfony\\Component\\HttpFoundation\\Request::getPathInfo` method returns
a cleaned URI (always returning ``/show`` and never ``/index.php/show``).
So, even if the user goes to ``/index.php/show``, the application is intelligent
enough to route the request through ``show_action()``.
Expand All @@ -520,8 +536,10 @@ The blog has come a *long* way, but it still contains a lot of code for such
a simple application. Along the way, you've made a simple routing
system and a method using ``ob_start()`` and ``ob_get_clean()`` to render
templates. If, for some reason, you needed to continue building this "framework"
from scratch, you could at least use Symfony's standalone `Routing`_ and
`Templating`_ components, which already solve these problems.
from scratch, you could at least use Symfony's standalone
:doc:`Routing </components/routing/introduction>` and
:doc:`Templating </components/templating/introduction>` components, which already
solve these problems.

Instead of re-solving common problems, you can let Symfony take care of
them for you. Here's the same sample application, now built in Symfony::
Expand Down Expand Up @@ -559,10 +577,14 @@ them for you. Here's the same sample application, now built in Symfony::
}
}

The two controllers are still lightweight. Each uses the
Notice, both controller functions now live inside a "controller class". This is a
nice way to group related pages. The controller functions are also sometimes called
*actions*.

The two controllers (or actions) are still lightweight. Each uses the
:doc:`Doctrine ORM library </book/doctrine>` to retrieve objects from the
database and the Templating component to render a template and return a
``Response`` object. The list template is now quite a bit simpler:
``Response`` object. The list ``list.php`` template is now quite a bit simpler:

.. code-block:: html+php

Expand All @@ -585,7 +607,7 @@ database and the Templating component to render a template and return a
<?php endforeach ?>
</ul>

The layout is nearly identical:
The ``layout.php`` file is nearly identical:

.. code-block:: html+php

Expand All @@ -605,12 +627,13 @@ The layout is nearly identical:

.. note::

The show template is left as an exercise, as it should be trivial to
create based on the list template.
The show ``show.php`` template is left as an exercise: updating it should be
really similar to updating the ``list.php`` template.

When Symfony's engine (called the ``Kernel``) boots up, it needs a map so
When Symfony's engine (called the Kernel) boots up, it needs a map so
that it knows which controllers to execute based on the request information.
A routing configuration map provides this information in a readable format:
A routing configuration map - ``app/config/routing.yml`` - provides this information
in a readable format:

.. code-block:: yaml

Expand All @@ -624,9 +647,8 @@ A routing configuration map provides this information in a readable format:
defaults: { _controller: AppBundle:Blog:show }

Now that Symfony is handling all the mundane tasks, the front controller
is dead simple. And since it does so little, you'll never have to touch
it once it's created (and if you use a `Symfony distribution`_, you won't
even need to create it!)::
``web/app.php`` is dead simple. And since it does so little, you'll never
have to touch it::

// web/app.php
require_once __DIR__.'/../app/bootstrap.php';
Expand All @@ -637,55 +659,29 @@ even need to create it!)::
$kernel = new AppKernel('prod', false);
$kernel->handle(Request::createFromGlobals())->send();

The front controller's only job is to initialize Symfony's engine (``Kernel``)
and pass it a ``Request`` object to handle. Symfony's core then uses the
routing map to determine which controller to call. Just like before, the
controller method is responsible for returning the final ``Response`` object.
There's really not much else to it.

For a visual representation of how Symfony handles each request, see the
:ref:`request flow diagram <request-flow-figure>`.

.. _where-symfony2-delivers:
The front controller's only job is to initialize Symfony's engine (called the
Kernel) and pass it a ``Request`` object to handle. The Symfony core
asks the router to inspect the request. The router matches the incoming URL
to a specific route and returns information about the route, including the
controller that should be executed. The correct controller from the matched
route is executed and your code inside the controller creates and returns the
appropriate ``Response`` object. The HTTP headers and content of the ``Response``
object are sent back to the client.

Where Symfony Delivers
~~~~~~~~~~~~~~~~~~~~~~

In the upcoming chapters, you'll learn more about how each piece of Symfony
works and the recommended organization of a project. For now, have a look
at how migrating the blog from flat PHP to Symfony has improved life:
It's a beautiful thing.

* Your application now has **clear and consistently organized code** (though
Symfony doesn't force you into this). This promotes **reusability** and
allows for new developers to be productive in your project more quickly;

* 100% of the code you write is for *your* application. You **don't need
to develop or maintain low-level utilities** such as autoloading,
:doc:`routing </book/routing>`, or rendering :doc:`controllers </book/controller>`;

* Symfony gives you **access to open source tools** such as Doctrine and the
Templating, Security, Form, Validation and Translation components (to name
a few);

* The application now enjoys **fully-flexible URLs** thanks to the Routing
component;

* Symfony's HTTP-centric architecture gives you access to powerful tools
such as **HTTP caching** powered by **Symfony's internal HTTP cache** or
more powerful tools such as `Varnish`_. This is covered in a later chapter
all about :doc:`caching </book/http_cache>`.

And perhaps best of all, by using Symfony, you now have access to a whole
set of **high-quality open source tools developed by the Symfony community**!
A good selection of Symfony community tools can be found on `KnpBundles.com`_.
.. figure:: /images/request-flow.png
:align: center
:alt: Symfony request flow

Better Templates
----------------
~~~~~~~~~~~~~~~~

If you choose to use it, Symfony comes standard with a templating engine
called `Twig`_ that makes templates faster to write and easier to read.
It means that the sample application could contain even less code! Take,
for example, the list template written in Twig:
for example, rewriting ``list.html.php`` template in Twig would look like
this:

.. code-block:: html+twig

Expand All @@ -707,7 +703,7 @@ for example, the list template written in Twig:
</ul>
{% endblock %}

The corresponding ``layout.html.twig`` template is also easier to write:
And rewriting ``layout.html.php`` template in Twig would look like this:

.. code-block:: html+twig

Expand All @@ -726,18 +722,52 @@ Twig is well-supported in Symfony. And while PHP templates will always
be supported in Symfony, the many advantages of Twig will continue to
be discussed. For more information, see the :doc:`templating chapter </book/templating>`.

Where Symfony Delivers
----------------------

In the upcoming chapters, you'll learn more about how each piece of Symfony
works and how you can organize your project. For now, celebrate at how migrating
the blog from flat PHP to Symfony has improved life:

* Your application now has **clear and consistently organized code** (though
Symfony doesn't force you into this). This promotes **reusability** and
allows for new developers to be productive in your project more quickly;

* 100% of the code you write is for *your* application. You **don't need
to develop or maintain low-level utilities** such as autoloading,
:doc:`routing </book/routing>`, or rendering :doc:`controllers </book/controller>`;

* Symfony gives you **access to open source tools** such as `Doctrine`_ and the
:doc:`Templating </components/templating/introduction>`,
:doc:`Security </components/security/introduction>`,
:doc:`Form </components/form/introduction>`, `Validator`_ and
:doc:`Translation </components/translation/introduction>` components (to name
a few);

* The application now enjoys **fully-flexible URLs** thanks to the Routing
component;

* Symfony's HTTP-centric architecture gives you access to powerful tools
such as **HTTP caching** powered by **Symfony's internal HTTP cache** or
more powerful tools such as `Varnish`_. This is covered in a later chapter
all about :doc:`caching </book/http_cache>`.

And perhaps best of all, by using Symfony, you now have access to a whole
set of **high-quality open source tools developed by the Symfony community**!
A good selection of Symfony community tools can be found on `KnpBundles.com`_.

Learn more from the Cookbook
----------------------------

* :doc:`/cookbook/templating/PHP`
* :doc:`/cookbook/controller/service`

.. _`Model-View-Controller`: https://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller
.. _`Doctrine`: http://www.doctrine-project.org
.. _`SQL injection attack`: https://en.wikipedia.org/wiki/SQL_injection
.. _`Composer`: https://getcomposer.org
.. _`download Composer`: https://getcomposer.org/download/
.. _`Routing`: https://github.com/symfony/routing
.. _`Templating`: https://github.com/symfony/templating
.. _`KnpBundles.com`: http://knpbundles.com/
.. _`Twig`: http://twig.sensiolabs.org
.. _`Validator`: https://github.com/symfony/validator
.. _`Varnish`: https://www.varnish-cache.org/
.. _`PHPUnit`: http://www.phpunit.de
.. _`Symfony distribution`: https://github.com/symfony/symfony-standard
.. _`KnpBundles.com`: http://knpbundles.com/
.. _`Twig`: http://twig.sensiolabs.org
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