Yesterday, we explored how symfony simplifies database management by abstracting the differences between database engines, and by converting the relational elements to nice object oriented classes. We have also played with Propel to describe the database schema, create the tables, and populate the database with some initial data.
Today, we are going to customize the basic job module we created
yesterday. The job module already has all the code we need for Jobeet:
- A page to list all jobs
- A page to create a new job
- A page to update an existing job
- A page to delete a job
Although the code is ready to be used as is, we will refactor the templates to match closer to the Jobeet mockups.
The MVC Architecture
If you are used to developing PHP websites without a framework, you probably use the one PHP file per HTML page paradigm. These PHP files probably contain the same kind of structure: initialization and global configuration, business logic related to the requested page, database records fetching, and finally HTML code that builds the page.
You may use a templating engine to separate the logic from the HTML. Perhaps you use a database abstraction layer to separate model interaction from business logic. But most of the time, you end up with a lot of code that is a nightmare to maintain. It was fast to build, but over time, it's more and more difficult to make changes, especially because nobody except you understands how it is built and how it works.
As with every problem, there are nice solutions. For web development, the most common solution for organizing your code nowadays is the MVC design pattern. In short, the MVC design pattern defines a way to organize your code according to its nature. This pattern separates the code into three layers:
The Model layer defines the business logic (the database belongs to this layer). You already know that symfony stores all the classes and files related to the Model in the
lib/model/directory.The View is what the user interacts with (a template engine is part of this layer). In symfony, the View layer is mainly made of PHP templates. They are stored in various
templates/directories as we will see later on today.The Controller is a piece of code that calls the Model to get some data that it passes to the View for rendering to the client. When we installed symfony the first day, we saw that all requests are managed by front controllers (
index.phpandfrontend_dev.php). These front controllers delegate the real work to actions. As we saw yesterday, these actions are logically grouped into modules.
Today, we will use the mockup defined in day 2 to customize the homepage and the job page. We will also make them dynamic. Along the way, we will tweak a lot of things in many different files to demonstrate the symfony directory structure and the way to separate code between layers.
The Layout
First, if you have a closer look at the mockups, you will notice that much of each page looks the same. You already know that code duplication is bad, whether we are talking about HTML or PHP code, so we need to find a way to prevent these common view elements from resulting in code duplication.
One way to solve the problem is to define a header and a footer and include them in each template:
But here the header and the footer files do not contain valid HTML. There must be a better way. Instead of reinventing the wheel, we will use another design pattern to solve this problem: the decorator design pattern. The decorator design pattern resolves the problem the other way around: the template is decorated after the content is rendered by a global template, called a layout in symfony:
The default layout of an application is called layout.php and can be
found in the apps/frontend/templates/ directory. This directory
contains all the global templates for an application.
Replace the default symfony layout with the following code:
<!-- apps/frontend/templates/layout.php --> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <title>Jobeet - Your best job board</title> <link rel="shortcut icon" href="/favicon.ico" /> <?php include_javascripts() ?> <?php include_stylesheets() ?> </head> <body> <div id="container"> <div id="header"> <div class="content"> <h1><a href="<?php echo url_for('job/index') ?>"> <img src="/legacy/images/logo.jpg" alt="Jobeet Job Board" /> </a></h1> <div id="sub_header"> <div class="post"> <h2>Ask for people</h2> <div> <a href="<?php echo url_for('job/index') ?>">Post a Job</a> </div> </div> <div class="search"> <h2>Ask for a job</h2> <form action="" method="get"> <input type="text" name="keywords" id="search_keywords" /> <input type="submit" value="search" /> <div class="help"> Enter some keywords (city, country, position, ...) </div> </form> </div> </div> </div> </div> <div id="content"> <?php if ($sf_user->hasFlash('notice')): ?> <div class="flash_notice"> <?php echo $sf_user->getFlash('notice') ?> </div> <?php endif; ?> <?php if ($sf_user->hasFlash('error')): ?> <div class="flash_error"> <?php echo $sf_user->getFlash('error') ?> </div> <?php endif; ?> <div class="content"> <?php echo $sf_content ?> </div> </div> <div id="footer"> <div class="content"> <span class="symfony"> <img src="/legacy/images/jobeet-mini.png" /> powered by <a href="/"> <img src="/legacy/images/symfony.gif" alt="symfony framework" /> </a> </span> <ul> <li><a href="">About Jobeet</a></li> <li class="feed"><a href="">Full feed</a></li> <li><a href="">Jobeet API</a></li> <li class="last"><a href="">Affiliates</a></li> </ul> </div> </div> </div> </body> </html>
A symfony template is just a plain PHP file. In the layout template, you
see calls to PHP functions and references to PHP variables. $sf_content is
the most interesting variable: it is defined by the framework itself and
contains the HTML generated by the action.
If you browse the job module (http://jobeet.localhost/frontend_dev.php/job),
you will see that all actions are now decorated by the layout.
The Stylesheets, Images, and JavaScripts
As this tutorial is not about web design, we have already prepared all the
needed assets we will use for Jobeet:
download the image files
archive and put them into the web/legacy/images/ directory;
download the stylesheet files
archive and put them into the web/css/ directory.
note
In the layout, we have included a favicon. You can
download the Jobeet one
and put it under the web/ directory.
tip
By default, the generate:project task has created three directories for the
project assets: web/legacy/images/ for images, web/~css|CSS~/ for
stylesheets, and web/js/ for JavaScripts. This is one of the
many conventions defined by symfony, but you can of course store
them elsewhere under the web/ directory.
The astute reader will have noticed that even if the main.css file is not
mentioned anywhere in the default layout, it is definitely present in the
generated HTML. But not the other ones. How is this possible?
The stylesheet file has been included by the include_stylesheets() function
call found within the layout <head> tag. The include_stylesheets()
function is called a helper. A helper is a function, defined by symfony,
that can take parameters and returns HTML code. Most of the time, helpers are
time-savers, they package code snippets frequently used in templates. The
include_stylesheets() helper generates <link> tags for stylesheets.
But how does the helper know which stylesheets to include?
The View layer can be configured by editing the view.yml configuration file
of the application. Here is the default one generated by the generate:app
task:
# apps/frontend/config/view.yml
default:
http_metas:
content-type: text/html
metas:
#title: symfony project
#description: symfony project
#keywords: symfony, project
#language: en
#robots: index, follow
stylesheets: [main.css]
javascripts: []
has_layout: on
layout: layout
The view.yml file configures the default settings for all the templates of
the application. For instance, the stylesheets entry defines an array of
stylesheet files to include for every page of the application (the inclusion
is done by the include_stylesheets() helper).
note
In the default view.yml configuration file, the referenced file is
main.css, and not /css/main.css. As a matter of fact, both definitions
are equivalent as symfony prefixes relative paths with /~css|CSS~/.
If many files are defined, symfony will include them in the same order as the definition:
stylesheets: [main.css, jobs.css, job.css]
You can also change the media attribute and omit the .css suffix:
stylesheets: [main.css, jobs.css, job.css, print: { media: print }]
This configuration will be rendered as:
<link rel="stylesheet" type="text/css" media="screen" href="/css/main.css" /> <link rel="stylesheet" type="text/css" media="screen" href="/css/jobs.css" /> <link rel="stylesheet" type="text/css" media="screen" href="/css/job.css" /> <link rel="stylesheet" type="text/css" media="print" href="/css/print.css" />
tip
The view.yml configuration file also defines the default layout used by the
application. By default, the name is layout, and so symfony decorates every
page with the layout.php file. You can also disable the decoration process
altogether by switching the has_layout entry to false.
It works as is but the jobs.css file is only needed for the homepage and the
job.css file is only needed for the job page. The view.yml configuration
file can be customized on a per-module basis. Change the stylesheets key of the
application view.yml file to only contain the main.css file:
# apps/frontend/config/view.yml stylesheets: [main.css]
To customize the view for the job module, create a view.yml file in the
apps/frontend/modules/job/config/ directory:
# apps/frontend/modules/job/config/view.yml indexSuccess: stylesheets: [jobs.css] showSuccess: stylesheets: [job.css]
Under the indexSuccess and showSuccess sections (they are the template
names associated with the index and show actions, as we will see later on),
you can customize any entry found under the default section of the
application view.yml. All specific entries are merged with the application
configuration. You can also define some configuration for all actions of a
module with the special all section.
As a rule of thumb, when something is configurable via a configuration file,
the same can be accomplished with PHP code. Instead of creating a view.yml
file for the job module for instance, you can also use the
use_stylesheet() helper to include a stylesheet from a template:
<?php use_stylesheet('main.css') ?>
You can also use this helper in the layout to include a stylesheet globally.
Choosing between one method or the other is really a matter of taste. The
view.yml file provides a way to define things for all actions of a module,
which is not possible in a template, but the configuration is quite static. On
the other hand, using the use_stylesheet() helper is more flexible and
moreover, everything is in the same place: the stylesheet definition and the
HTML code. For Jobeet, we will use the use_stylesheet() helper, so you can
remove the view.yml we have just created and update the job templates with
the use_stylesheet() calls:
<!-- apps/frontend/modules/job/templates/indexSuccess.php --> <?php use_stylesheet('jobs.css') ?> <!-- apps/frontend/modules/job/templates/showSuccess.php --> <?php use_stylesheet('job.css') ?>
note
Symmetrically, the JavaScript configuration is done via the javascripts
entry of the view.yml configuration file and the use_javascript() helper
defines JavaScript files to include for a template.
The Job Homepage
As seen in day 3, the job homepage is generated by the index action of the
job module. The index action is the Controller part of the page and the
associated template, indexSuccess.php, is the View part:
apps/
frontend/
modules/
job/
actions/
actions.class.php
templates/
indexSuccess.php
The Action
Each action is represented by a method of a class. For the job homepage, the
class is jobActions (the name of the module suffixed by Actions) and the
method is executeIndex() (execute suffixed by the name of the action).
It retrieves all the jobs from the database:
// apps/frontend/modules/job/actions/actions.class.php class jobActions extends sfActions { public function executeIndex(sfWebRequest $request) { $this->jobeet_job_list = JobeetJobPeer::doSelect(new Criteria()); } // ... }
Let's have a closer look at the code: the executeIndex() method (the
Controller) calls the Model JobeetJobPeer to retrieve all the jobs
(new Criteria()). It returns an array of JobeetJob objects that are assigned to
the jobeet_job_list object property.
All such object properties are then automatically passed to the template (the View). To pass data from the Controller to the View, just create a new property:
public function executeFooBar(sfWebRequest $request) { $this->foo = 'bar'; $this->bar = array('bar', 'baz'); }
This code will make $foo and $bar variables accessible in the template.
The Template
By default, the template name associated with an action is deduced by symfony
thanks to a convention (the action name suffixed by Success).
The indexSuccess.php template generates an HTML table for all the jobs. Here
is the current template code:
<!-- apps/frontend/modules/job/templates/indexSuccess.php --> <?php use_stylesheet('jobs.css') ?> <h1>Job List</h1> <table> <thead> <tr> <th>Id</th> <th>Category</th> <th>Type</th> <!-- more columns here --> <th>Created at</th> <th>Updated at</th> </tr> </thead> <tbody> <?php foreach ($jobeet_job_list as $jobeet_job): ?> <tr> <td> <a href="<?php echo url_for('job/show?id='.$jobeet_job->getId()) ?>"> <?php echo $jobeet_job->getId() ?> </a> </td> <td><?php echo $jobeet_job->getCategoryId() ?></td> <td><?php echo $jobeet_job->getType() ?></td> <!-- more columns here --> <td><?php echo $jobeet_job->getCreatedAt() ?></td> <td><?php echo $jobeet_job->getUpdatedAt() ?></td> </tr> <?php endforeach; ?> </tbody> </table> <a href="<?php echo url_for('job/new') ?>">New</a>
In the template code, the foreach iterates through the list of Job objects
($jobeet_job_list), and for each job, each column value is output.
Remember, accessing a column value is as simple as calling an accessor method
which name begins with get and the camelCased column name
(for instance the getCreatedAt() method for the created_at column).
Let's clean this up a bit to only display a sub-set of the available columns:
<!-- apps/frontend/modules/job/templates/indexSuccess.php --> <?php use_stylesheet('jobs.css') ?> <div id="jobs"> <table class="jobs"> <?php foreach ($jobeet_job_list as $i => $job): ?> <tr class="<?php echo fmod($i, 2) ? 'even' : 'odd' ?>"> <td class="location"><?php echo $job->getLocation() ?></td> <td class="position"> <a href="<?php echo url_for('job/show?id='.$job->getId()) ?>"> <?php echo $job->getPosition() ?> </a> </td> <td class="company"><?php echo $job->getCompany() ?></td> </tr> <?php endforeach; ?> </table> </div>
The url_for() function call in this template is a symfony helper that we
will discuss tomorrow.
The Job Page Template
Now let's customize the template of the job page. Open the showSuccess.php
file and replace its content with the following code:
<!-- apps/frontend/modules/job/templates/showSuccess.php --> <?php use_stylesheet('job.css') ?> <?php use_helper('Text') ?> <div id="job"> <h1><?php echo $job->getCompany() ?></h1> <h2><?php echo $job->getLocation() ?></h2> <h3> <?php echo $job->getPosition() ?> <small> - <?php echo $job->getType() ?></small> </h3> <?php if ($job->getLogo()): ?> <div class="logo"> <a href="<?php echo $job->getUrl() ?>"> <img src="/uploads/jobs/<?php echo $job->getLogo() ?>" alt="<?php echo $job->getCompany() ?> logo" /> </a> </div> <?php endif; ?> <div class="description"> <?php echo simple_format_text($job->getDescription()) ?> </div> <h4>How to apply?</h4> <p class="how_to_apply"><?php echo $job->getHowToApply() ?></p> <div class="meta"> <small>posted on <?php echo $job->getCreatedAt('m/d/Y') ?></small> </div> <div style="padding: 20px 0"> <a href="<?php echo url_for('job/edit?id='.$job->getId()) ?>"> Edit </a> </div> </div>
This template uses the $job variable passed by the action to display the job
information. As we have renamed the variable passed to the template from
$jobeet_job to $job, you need to also make this change in the show action
(be careful, there are two occurrences of the variable):
// apps/frontend/modules/job/actions/actions.class.php public function executeShow(sfWebRequest $request) { $this->job = JobeetJobPeer::retrieveByPk($request->getParameter('id')); $this->forward404Unless($this->job); }
Notice that some Propel accessors take arguments. As we have defined
the created_at column as a timestamp, the getCreatedAt() accessor takes a date
formatting pattern as its first argument:
$job->getCreatedAt('m/d/Y');
note
The job description uses the simple_format_text() helper to format it as
HTML, by replacing carriage returns with <br /> for instance. As this helper
belongs to the Text helper group, which is not loaded by default, we have
loaded it manually by using the use_helper() helper.
Slots
Right now, the title of all pages is defined in the <title> tag of the
layout:
<title>Jobeet - Your best job board</title>
But for the job page, we want to provide more useful information, like the company name and the job position.
In symfony, when a zone of the layout depends on the template to be displayed, you need to define a slot:
Add a slot to the layout to allow the title to be dynamic:
// apps/frontend/templates/layout.php <title><?php include_slot('title') ?></title>
Each slot is defined by a name (title) and can be displayed by using the
~include_slot~() helper. Now, at the beginning of the showSuccess.php
template, use the slot() helper to define the content of the slot for the
job page:
// apps/frontend/modules/job/templates/showSuccess.php <?php slot( 'title', sprintf('%s is looking for a %s', $job->getCompany(), $job->getPosition())) ?>
If the title is complex to generate, the slot() helper can also be used
with a block of code:
// apps/frontend/modules/job/templates/showSuccess.php <?php slot('title') ?> <?php echo sprintf('%s is looking for a %s', $job->getCompany(), $job->getPosition()) ?> <?php end_slot(); ?>
For some pages, like the homepage, we just need a generic title. Instead of repeating the same title over and over again in templates, we can define a default title in the layout:
// apps/frontend/templates/layout.php <title> <?php if (!include_slot('title')): ?> Jobeet - Your best job board <?php endif; ?> </title>
The include_slot() helper returns true if the slot has been defined. So,
when you define the title slot content in a template, it is used; if not,
the default title is used.
tip
We have already seen quite a few helpers beginning with include_. These helpers
output the HTML and in most cases have a get_ helper counterpart to
just return the content:
<?php include_slot('title') ?> <?php echo get_slot('title') ?> <?php include_stylesheets() ?> <?php echo get_stylesheets() ?>
The Job Page Action
The job page is generated by the show action, defined in the executeShow()
method of the job module:
class jobActions extends sfActions { public function executeShow(sfWebRequest $request) { $this->job = JobeetJobPeer::retrieveByPk($request->getParameter('id')); $this->forward404Unless($this->job); } // ... }
As in the index action, the JobeetJobPeer class is used to retrieve a job,
this time by using the retrieveByPk() method. The parameter of this method
is the unique identifier of a job, its primary key. The next
section will explain why the $request->getParameter('id') statement returns
the job primary key.
tip
The generated model classes contain a lot of useful methods to interact with
the project objects. Take some time to browse the code located in the
lib/om/ directory and discover all the power embedded in these classes.
If the job does not exist in the database, we want to forward the user to a
404 page, which is exactly what the forward404Unless() method does. It
takes a Boolean as its first argument and, unless it is true, stops the current
flow of execution. As the forward methods stops the execution of the action
right away by throwing a sfError404Exception, you don't need to return
afterwards.
As for exceptions, the page displayed to the user is
different in the prod environment and in the dev environment:
note
Before you deploy the Jobeet website to the production server, you will learn how to customize the default 404 page.
The Request and the Response
When you browse to the /job or /job/show/id/1 pages in your browser, your
are initiating a round trip with the web server. The browser is sending a
request and the server sends back a response.
We have already seen that symfony encapsulates the request in a sfWebRequest
object (see the executeShow() method signature). And as symfony is an
Object-Oriented framework, the response is also an object, of class
sfWebResponse. You can access the response object in an action by calling
$this->getResponse().
These objects provide a lot of convenient methods to access information from PHP functions and PHP global variables.
note
Why does symfony wrap existing PHP functionalities? First, because the
symfony methods are more powerful than their PHP counterpart. Then, because
when you test an application, it is much more easier to simulate a request or
a response object than trying to fiddle around with global variables or work
with PHP functions like header() which do too much magic behind the scene.
The Request
The sfWebRequest class wraps the $_SERVER, $_COOKIE, $_GET, $_POST,
and $_FILES PHP global arrays:
| Method name | PHP equivalent |
|---|---|
getMethod() |
$_SERVER['REQUEST_METHOD'] |
getUri() |
$_SERVER['REQUEST_URI'] |
getReferer() |
$_SERVER['HTTP_REFERER'] |
getHost() |
$_SERVER['HTTP_HOST'] |
getLanguages() |
$_SERVER['HTTP_ACCEPT_LANGUAGE'] |
getCharsets() |
$_SERVER['HTTP_ACCEPT_CHARSET'] |
isXmlHttpRequest() |
$_SERVER['X_REQUESTED_WITH'] == 'XMLHttpRequest' |
getHttpHeader() |
$_SERVER |
getCookie() |
$_COOKIE |
isSecure() |
$_SERVER['HTTPS'] |
getFiles() |
$_FILES |
getGetParameter() |
$_GET |
getPostParameter() |
$_POST |
getUrlParameter() |
$_SERVER['PATH_INFO'] |
getRemoteAddress() |
$_SERVER['REMOTE_ADDR'] |
We have already accessed request parameters by using the getParameter()
method. It returns a value from the $_GET or $_POST global variable, or
from the ~PATH_INFO~ variable.
If you want to ensure that a request parameter comes from a particular one of
these variables, you need use the getGetParameter(), getPostParameter(),
and getUrlParameter() methods respectively.
note
When you want to restrict an action for a specific HTTP method,
for instance when you want to ensure that a form is submitted as a POST,
you can use the isMethod() method:
$this->forwardUnless($request->isMethod('POST'));.
The Response
The sfWebResponse class wraps the ~header|HTTP Headers~() and
setraw~cookie|Cookies~() PHP methods:
| Method name | PHP equivalent |
|---|---|
setCookie() |
setrawcookie() |
setStatusCode() |
header() |
setHttpHeader() |
header() |
setContentType() |
header() |
addVaryHttpHeader() |
header() |
addCacheControlHttpHeader() |
header() |
Of course, the sfWebResponse class also provides a way to set the content of
the response (setContent()) and send the response to the browser (send()).
Earlier today we saw how to manage stylesheets and JavaScripts in both the
view.yml file and in templates. In the end, both techniques use the response
object addStylesheet() and addJavascript() methods.
tip
The sfAction,
sfRequest, and
sfResponse classes
provide a lot of other useful methods. Don't hesitate to browse the
API documentation to learn more
about all symfony internal classes.
See you Tomorrow
Today, we have described some design patterns used by symfony. Hopefully the project directory structure now makes more sense. We have played with the templates by manipulating the layout and the template files. We have also made them a bit more dynamic thanks to slots and actions.
Tomorrow, we will learn more about the url_for() helper we have used today,
and the routing sub-framework associated with it.
This work is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported License license.