Manual 5

Cook up Web sites fast with CakePHP, Part 1:
Getting started
Quick and easy PHP rapid-development aid
Skill Level: Intermediate
Duane O'Brien (d@duaneobrien.com)
PHP developer
Freelance
21 Nov 2006
Updated 22 Jan 2008
CakePHP is a stable production-ready, rapid-development aid for building Web sites
in PHP. This "Cook up Web sites fast with CakePHP" series shows you how to build
an online product catalog using CakePHP.
Section 1. Before you start
Editor's note: This series was originally published in 2006 and 2007. Since its
publication, CakePHP developers made significant changes to CakePHP, which
made this series obsolete. In response to these changes and the popularity of this
series, the authors revised each of its five parts to make it compliant with the version
of CakePHP available in January 2008.
This "Cook up Web sites fast with CakePHP" series is designed for PHP application
developers who want to start using CakePHP to make their lives easier. In the end,
you will have learned how to install and configure CakePHP, the basics of
Model-View-Controller (MVC) design, how to validate user data in CakePHP, how to
use CakePHP helpers, and how to get an application up and running quickly using
CakePHP. It might sound like a lot to learn, but don't worry — CakePHP does most
of it for you.
About this series
Getting started
© Copyright IBM Corporation 1994, 2008. All rights reserved. Page 1 of 36

• Part 1 focuses on getting CakePHP up and running, and the basics of
how to put together a simple application allowing users to register for an
account and log in to the application.
• Part 2 demonstrates how to use scaffolding and Bake to get a jump-start
on your application, and using CakePHP's access-control lists (ACLs).
• Part 3 shows how to use Sanitize, a handy CakePHP class, which helps
secure an application by cleaning up user-submitted data. Part 3 also
covers the CakePHP Security component, handling invalid requests, and
other advanced request authentication.
• Part 4 focuses primarily on the Session component of CakePHP,
demonstrating three ways to save session data, as well as the Request
Handler component to help you manage multiple types of requests
(mobile browsers, requests containing XML or HTML, etc).
• Part 5 deals with caching, specifically view and layout caching, which can
help reduce server resource consumption and speed up your application.
About this tutorial
This tutorial shows you how to get started using CakePHP. You'll go through the
installation process, then get down and dirty by building the online product gallery.
And through it all, you'll see how much time you could have saved had you been
using CakePHP all along. This part of the tutorial builds the online product
application, Tor, which includes a "request dealership username and password"
page and a login page.
CakePHP topics include:
• MVC design
• Helpers
• CakePHP data validation
Prerequisites
It is assumed that you are familiar with the PHP programming language, have a
fundamental grasp of database design, and are comfortable getting your hands dirty.
A full grasp of the MVC design pattern is not necessary, as the fundamentals will be
covered during this tutorial. More than anything, you should be eager to learn, ready
to jump in, and anxious to speed up your development time.
System requirements
Before you begin, you need to have an environment in which you can work.
developerWorks® ibm.com/developerWorks
Getting started
Page 2 of 36 © Copyright IBM Corporation 1994, 2008. All rights reserved.

CakePHP has reasonably minimal server requirements:
1. An HTTP server that supports sessions (and preferably mod_rewrite).
This tutorial was written using Apache V2.2.4 with mod_rewrite
enabled.
2. PHP V4.3.2 or later (including PHP V5). This tutorial was written using
PHP V5.2.3
3. A supported database engine. this tutorial was written using MySQL
V5.0.4
You'll also need a database ready for your application to use. The tutorial will
provide syntax for creating any necessary tables in MySQL.
The simplest way to download CakePHP is to visit CakeForge.org and download the
latest stable version. This tutorial was written using V1.2.0. Nightly builds and copies
straight from Subversion are also available. Details are in the CakePHP Manual (see
Resources).
Section 2. Installation
CakePHP wants to make your life easier, regardless of your level of experience, by
making your applications easier to maintain and quicker to write. CakePHP is full of
cool and useful features. CakePHP wants to handle your Ajax, your data validation,
your sessions. It will even slice your bread if you can write a plug-into tell it how. But
you can't use CakePHP yet. You need to install it first.
Unpack and install
For the purpose of this tutorial, the entire CakePHP installation directory should be
unpacked within the webroot of your Web server. In Listing 1, the webroot is
/webroot.
Listing 1. Unpacking the CakePHP installation directory
unzip cake_1.2.0.5875-pre-beta.zip
cd cake_1.2.0.5875-pre-beta
mv * /webroot
Type ls -la /webroot to list the contents of the webroot and verify that the files
have been moved properly. The output should look something like Listing 2.
Listing 2. Output of the ls command
ibm.com/developerWorks developerWorks®
Getting started

drwxr-xr-x 12 YOURUSER YOURGROUP 4096 2007-12-15 22:50 app
drwxr-xr-x 7 YOURUSER YOURGROUP 4096 2007-12-15 22:50 cake
drwxr-xr-x 2 YOURUSER YOURGROUP 4096 2007-12-15 22:50 docs
-rw-r--r-- 1 YOURUSER YOURGROUP 139 2007-12-15 22:50 .htaccess
-rw-r--r-- 1 YOURUSER YOURGROUP 2303 2007-12-15 22:50 index.php
drwxr-xr-x 5 YOURUSER YOURGROUP 4096 2007-12-15 22:50 vendors
The directory app/tmp needs to be writable by your Web server. Confirm the
permissions on this folder by typing ls -l app. The output will probably look
similar to Listing 3.
Listing 3. Confirming folder permissions
drwxr-xr-x 3 YOURUSER YOURGROUP 4096 2007-12-15 22:50 config
drwxr-xr-x 3 YOURUSER YOURGROUP 4096 2007-12-15 22:50 controllers
-rw-r--r-- 1 YOURUSER YOURGROUP 953 2007-12-15 22:50 index.php
drwxr-xr-x 3 YOURUSER YOURGROUP 4096 2007-12-15 22:50 locale
drwxr-xr-x 3 YOURUSER YOURGROUP 4096 2007-12-15 22:50 models
drwxr-xr-x 2 YOURUSER YOURGROUP 4096 2007-12-15 22:50 plugins
drwxr-xr-x 5 YOURUSER YOURGROUP 4096 2007-12-15 22:50 tests
drwxr-xr-x 6 YOURUSER YOURGROUP 4096 2007-12-15 22:50 tmp
drwxr-xr-x 3 YOURUSER YOURGROUP 4096 2007-12-15 22:50 vendors
drwxr-xr-x 8 YOURUSER YOURGROUP 4096 2007-12-15 22:50 views
drwxr-xr-x 6 YOURUSER YOURGROUP 4096 2007-12-15 22:50 webroot
The simplest way to accomplish this is probably the most common and least secure:
give write permissions to everyone:
chmod -R 777 app/tmp
ls -l app
The permissions for the tmp folder should have been updated, as shown below:
drwxrwxrwx 7 YOURUSER YOURGROUP 2007-12-15 22:50 tmp
Giving write permissions to everyone is not recommended for general use. Ideally,
you should change the ownership of this folder to match the user that the Web
server uses, or add the user that the Web server uses to a the group for the
directory and add group write permissions. This tutorial is intended to demonstrate
how to use CakePHP and is not designed to be a guide for building secure
applications. While security should be at the head of any application development, a
full discussion of secure PHP practices is outside the scope of this tutorial.
For a production installation, change the webroot of the Web server to app/webroot,
which will minimize the amount of code accessible via the Web browser and help
enhance the security of your installation.
Validation 1
In a browser, go to the URL that corresponds with the webroot for your Web server.
Getting started

For example, if you've installed CakePHP into the webroot of your localhost, go to
http://localhost. You should see the CakePHP default home page.
Figure 1. The CakePHP default home page as it should be seen
Note: If the default home page looks more like Figure 2, then mod_rewrite is not
working the way CakePHP requires. This can sometimes be a problem for first-time
users.
Figure 2. The incorrect-looking home page
Getting started

Is your .htaccess file correct?
You should have gotten an .htaccess file in the CakePHP installation directory. On
most *nix systems, this will be hidden from view by default. If you do not have the
file, check the source you downloaded or get a fresh update from CakePHP.org.
Confirm that the file exists and is valid by going to the installation directory and
running cat .htaccess. This will display the file's contents, which should look like
Listing 4.
Listing 4. Confirming the that the .htaccess file exists
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteRule ^$ app/webroot/ [L]
RewriteRule (.*) app/webroot/$1 [L]
</IfModule>
Is mod_rewrite enabled for the server?
Getting started

Make sure that mod_rewrite is enabled for your Web server. For Apache, there
are two different lines that should appear in the httpd.conf file. In the LoadModule
list, you should see the following line (or something very close): LoadModule
rewrite_module libexec/mod_rewrite.so.
In the AddModule list, you should see this line (or something very close):
AddModule mod_rewrite.c.
If you cannot find these lines in your httpd.conf file, mod_rewrite is not enabled.
Consult your server documentation for details on how to do this.
Does the server allow .htaccess override?
Make sure your Web server is configured to allow .htaccess override. For Apache,
each directory should be defined in the httpd.conf file. These definitions can look
very different from installation to installation, but you should still see the line
AllowOverride All in the definition. Your definition might look something like Listing 5.
Listing 5. Definitions in the httpd.conf file
<Directory "/webroot">
Options Indexes MultiViews
AllowOverride All
Order allow,deny
Allow from all
</Directory>
Consult your server documentation for more details about .htaccess override.
Configuring a database connection
Now that you've got CakePHP installed and on speaking terms with your Web
server, you need to introduce CakePHP to your database. This section will cover
setting up the database configuration and verifying that CakePHP likes your
database. Tor is going to need a place to store its user and product data. You'll be
soon be creating a users table to be used to build the login and registration parts of
Tor.
Editing the database configuration file
Setting up your database configuration is pretty darn easy, but before you start,
make sure your database server is running, that you have created a database for
your application, and that you have a user name and password for a user with rights
to the database.
To start, make a copy of the app/config/database.php.default file and save it as
app/config/database.php. Do this to preserve a copy of the original template. Open
the file in your favorite text editor and look for the following section (it should be just
near the bottom of the file).
Getting started

Listing 6. The app/config/database.php.default file
var $default = array(
'driver' => 'mysql',
'persistent' => false,
'host' => 'localhost',
'port' => '',
'login' => 'user',
'password' => 'password',
'database' => 'database_name',
'schema' => '',
'prefix' => '',
'encoding' => ''
);
Modify this information to fit your installation:
driver
This can be mysql, mysqli, postgres, sqlite, mssql, db2, oracle,
adodb or pear-drivername. This tutorial assumes mysql.
persistent
This field tells CakePHP whether it should use persistent database
connections. This should be true or false. This tutorial assumes false.
host
This is the hostname of your database server, such as localhost or
mysql.yourdomain.
port
If your database is running on a nonstandard port, you can specify which port
to use here.
login
This is the user name for your database login, such as dbuser.
password
This is the password for your database login, such as secretsecret.
database
This is the name of the database you wish to use, such as cakedev.
schema
This is used to specify what schema will be used. This can be left blank.
Schema will not be covered in this series.
prefix
Prefix is a string, such as cp_, that is prepended to table names for any
database call made by CakePHP. Using a prefix may be necessary if the
database is shared among applications to keep tables from stepping on each
other where two or more applications want a table with the same name, such
as users.
Getting started

encoding
This is used to specify what encoding is used by the database. This can be left
blank for this series.
Don't forget to save the file.
Any number of database configurations can be specified in database.php provided
they have distinct names. You can specify which database configuration the
application should use in the models.
Some notes about databases and CakePHP:
• The tables must have a primary key named id.
• If you include a created or modified column in the table, CakePHP will
automatically populate the field when appropriate.
• Table names should be plural (users, products, eggs, sodas, winners,
losers). Their corresponding models will have singular names (user,
product, egg, soda, winner, loser).
• If tables are to be related, foreign keys should follow the format
table_id with singular table names. For example, user_id,
product_id, egg_id, soda_id, winner_id and loser_id would be
foreign keys for the table's user, product, egg, soda, winner, and loser.
Validation 2
Go back to the URL you used to validate the initial installation. You should see that
the CakePHP default home page has changed to indicate the status of your
database configuration.
Figure 3. CakePHP default home page has changed to indicate status of
database configuration
Getting started

If the default home page says the database configuration file is not present, you may
have put it in the wrong place or misnamed it. Make sure the database configuration
file is app/config/database.php. If the default home page says CakePHP is unable to
connect to the database, confirm that the connection information you entered is valid
and retry.
Creating the application tables
So now CakePHP, your Web server, and your database are all on speaking terms.
Time to roll up your sleeves and get to the real work. Tor needs a users table.
This table will contain the basic information necessary to identify and interact with a
user. A simple user name and password field would probably suffice, but other
information can be useful, such as an e-mail address (for sending password reset
requests), first and last name (for personalization), and last login date (to help track
Getting started

inactive accounts). You probably want your user name and e-mail fields to be
unique. And don't forget the primary key ID field. The SQL to create your table might
look something like Listing 7.
Listing 7. SQL to create your table
CREATE TABLE ùsers` (
ìd` INT( 10 ) NOT NULL AUTO_INCREMENT PRIMARY KEY ,
ùsername` VARCHAR( 40 ) NOT NULL ,
`password` VARCHAR( 40 ) NOT NULL ,
èmail` VARCHAR( 255 ) NOT NULL ,
`first_name` VARCHAR( 40 ) NOT NULL ,
`last_name` VARCHAR( 40 ) NOT NULL ,
UNIQUE (username , email )
) TYPE = MyISAM
Notice that the username, password, first_name, and last_name fields have a
maximum character length of 40. We will enforce this character length in the user
model. The 40-character maximum length, in this case, is entirely arbitrary.
Section 3. MVC design
It's common enough at this point to jump in and start cranking out code based on
what the application is intended to do. A login page, a database, registration —
BAM! Simple enough. And it usually is. Until you want to change how it looks, how it
interacts with the database, change validation rules, or change essentially anything
about the application at all. Then things start to get complicated.
CakePHP is designed to make writing the application as easy as possible, while
giving you something you can maintain long-term. Tor will be built using the MVC
design pattern. The tutorial will show you how. CakePHP will show you how it can be
easy. You'll see for yourself why it makes sense.
The MVC design pattern breaks an application into three distinct layers: handling
Data, UI and Logic, respectively. MVC was first described in the book Design
Patterns: Elements of Reusable Object-Oriented Software, also known as the "Gang
Of Four" book. A full discussion of design patterns and MVC is outside the scope of
this tutorial, but it will be helpful to touch on what the three pieces mean —
specifically, in the CakePHP world.
Model
Users, products, prices, messages — when you boil it all down, it's all just data. You
make sure the data is what you want, it goes into a database, then you have to get it
back out. It will be useful for all the data-handling aspects of Tor to live in one place.
That where model comes in.
Getting started

Model is primarily concerned with handling data. Getting data from a database,
inserting data into a database, validating data — all of this takes place within the
model.
An individual model typically is used to access a specific table in the database.
Generally, a model will associate to a database table if the table name is a plural
form of the model name. For example, a product model will, by default, associate to
a products table.
All user-defined models will extend the CakePHP AppModel class.
The user model
Having created a users table for Tor, you will need a user model to interact with the
table. The user model will save your user data, get it back out of the table for you,
and verify that the user data is in an acceptable format. For now, this model can be a
stub. It should be created as app/models/user.php and might look something like
Listing 8.
Listing 8. The user model
<?php
class User extends AppModel
{
var $name = 'User';
}
?>
Notice the line var $name = 'User';. It is accepted as best practice to specify
the name of the model in $name.
View
Being able to save, retrieve, and validate your data is pretty useless without some
means of displaying the data. By putting all display and presentation code in one
place, you can change the look and feel of your application without having to work
around application logic and data-related code.
View is primarily concerned with formatting data for presentation to the user. The
view represents any and all UI work, including all templates and HTML. CakePHP's
view files are regular HTML files embedded with PHP code.
Ultimately, a view is just a page template. Usually, the view will be named after the
action associated with it. For example, a display() action would normally have a
display view.
Returning to the sample application, we have created a users table and a user
model to interact with this table. Now we need some views. The user will need to
register an account and log in to the application. This calls for a register and a login
Getting started

view.
The register view
Before a user can use the Tor application, he will need to register an account. This
will require a register view, which will present the registration form to the user. You
should already know what kind of user information Tor is looking for. Specifically,
you will need to collect a user name, password, e-mail address, and first and last
name.
The register view should be created as app/views/users/register.ctp and might look
something like that shown in Listing 9.
Listing 9. The register view
<form action="/users/register" method="post">
<p>Please fill out the form below to register an account.</p>
<label>Username:</label><input name="username" size="40" />
<label>Password:</label><input type="password" name="password" size="40"
/>
<label>Email Address:</label><input name="email" size="40"
maxlength="255" />
<label>First Name:</label><input name="first_name" size="40" />
<label>Last Name:</label><input name="last_name" size="40" />
<input type="submit" value="register" />
</form>
It is important to note that the field names are the same as the column names in
your database. This will come into play when we get to the users controller. Later,
when you learn a little more about Cake and see how Cake Helpers work, you will
rewrite this page completely, but for now, this page is regular HTML, just like you
have probably always written.
Controller
With data handling all contained within in the model and the presentation layer all
contained within the view, the rest of the application is going to live in the controller.
This is where logic, decision-making, workflow, and generally anything that the
application does will happen. The model manages your data, the view shows it to
you, the controller does everything else.
The controller manages server requests. It accepts user input (URL requests, form
POSTs, GET requests, etc.), applies logic where necessary, invokes models where
data handling is required, and sends output through the appropriate view.
Generally, a controller will manage logic for a single model. A controller contains any
number of functions, referred to as actions. An action typically applies logic and
Getting started

displays a view. All user-defined controllers will need to extend the CakePHP
AppController class.
In Tor, you have created a users table, a user model to interact with the table, and
views to present registration and login forms to the user. Those forms will submit to
the users controller, invoking the register and login actions, respectively. The users
controller should be created as app/controllers/users_controller.php and should start
out looking something like Listing 10.
Listing 10. The users controller
<?php
class UsersController extends AppController
{
}
?>
The register action
You now have a controller. But it's not doing anything yet. Before it will do anything
for you, you'll have to give it some actions to perform.
Now you are getting down to the nuts and bolts. The user has filled out a form and
submitted it to the application. We will cover data validation later. For now, we will
just push it into the database. We do this by adding the register action to the
users controller.
Listing 11. The register action
<?php
{
function register()
{
if (!empty($this->params['form']))
{
if ($this->User->save($this->params['form']))
{
$this->flash('Your registration information was accepted.',
'/users/register');
} else {
$this->flash('There was a problem with your registration',
'/users/register');
}
}
}
}
?>
The register action starts by looking at the form ($this->params['form']) to
see if it was submitted. If the form was not submitted, the action will not do anything.
Once you know the form was submitted with data, the controller calls the save
method on the user model, which is an extension of AppModel. The save method
will, by default, look for a table that's a plural of the model itself. In this case, it is
looking for a users table to go with the user model. If the table is found, the save
Getting started

method will turn the passed array ($this->params['form']) into an INSERT
statement, using the array keys as column names and the array values as the
INSERT values.
In this case, $this->params['form'] will look like Listing 12.
Listing 12. The $this->params['form'] array
Array
(
[CAKEPHP] => b975a875bdba3bdff38ea0eda8c3375f
[username] => zaphod
[password] => secret
[email] => beeblebrox@heartofgold.hhg
[first_name] => zaphod
[last_name] => beeblebrox
)
The save method will ignore the CAKEPHP session key and build an INSERT
statement from the rest. It would look something like Listing 13.
Listing 13. INSERT statement
INSERT INTO
users
(username, password, email, first_name, last_name)
VALUES
('zaphod', 'secret', 'beeblebrox@heartofgold.hhg', 'zaphod', 'beeblebrox')
It should now be apparent why you used the database column names in the register
view for the register form field names. By doing so, you simplified the process of
saving your data significantly.
To continue, if the data inserts successfully, the register action calls the Flash
method. Flash presents a basic message to the user (in this case, a success or
failure message) with a link away from the message (in this case, back to the
register view, since nothing else has been defined.
Now that you have a user model to interface with your users table, and a register
view to show a registration form, and a users controller with a register action, you
can actually see your application in action.
Try it out
All the pieces have fallen into place. It's time to bring Tor to life. Fire up your browser
and jump in.
Load the register view by going to http://localhost/users/register. You should see
something like Figure 4.
Figure 4. Loading the register view
Getting started

Fill out and submit the form. You should see your success message.
Figure 5. Success message
Getting started

If you look in your database, you should see a record corresponding to your form
submission, complete with a plain-text password (a terribly bad idea, which we will
fix later).
Try to fill out the form again, using the same information. You should see the failure
message.
Figure 6. Register failure
Getting started

If you are using a database that supports the UNIQUE field restraint, the registration
will fail. During the creation of the users table, the user name and e-mail fields were
defined as UNIQUE, meaning values for those fields cannot be duplicated. CakePHP
recognizes the error when the database throws it and displays an error.
Section 4. Helpers
Helpers in CakePHP exist primarily to help speed up the development of your views.
There are helpers for HTML, Ajax, JavaScript and more. Helpers make it easier to
insert pieces of HTML code you find yourself writing multiple times.
Getting started

Modifying the users_controller.php file
In order to start using helpers, you will need to modify the users_controller.php file
you created earlier. You should give the controller a name, and tell it that you want
to use some helpers, in this case, the HTML and Form helpers. Edit the file to add
the $name and $helpers class variables, as shown in Listing 14.
Listing 14. The users controller
<?php
{
var $name = 'Users';
var $helpers = array('Html', 'Form' );
function register()
{
...
Now that you have included your helpers, you can begin using them.
Making tables easier
Users of Tor should be able to see who else is registered to use the application.
CakePHP has a number of helpers in place to assist with creating tables. These
helpers include many useful bits of functionality, some of which you have probably
written more than once. To demonstrate this capability, you will create a view to
display registered users.
Creating a knownusers action
Start by creating a knownusers action in the users controller.
Listing 15. Creating a knownusers action
function knownusers()
{
$this->set('knownusers',
$this->User->findAll(null, array('id', 'username', 'first_name',
'last_name'), 'id DESC')
);
}
This calls the built in findAll function on the user model. The findAll function
takes a field containing conditions (in this case, you passed null conditions, which
will return all users), an array of fields to be returned (we don't want all of the user
information, just what you would want everyone to see), and a sort field and order (in
this case, id DESC to sort the fields in descending order by ID). You can also
specify a limit (maximum rows to return), page (if you are paging the data), and a
recursive option, which can be specified to return models associated with the data
(for example, if you were querying a groups table and several users belong to each
group).
Getting started

The output from findAll is put into the knownusers variable. The data can now
be accessed from a view.
Creating the knownusers view
Create the file app/views/users/knownusers.ctp in a text editor. To see what the data
returned by findAll looks like, output the knownusers variable using var_dump.
Listing 16. Output the knownusers variable using var_dump
<pre>
<?php var_dump($knownusers) ?>
</pre>
Visit the view at http://localhost/users/knownusers. You should see an array of user
data.
Figure 7. The results
Getting started

If you only have one user listed, go back to http://localhost/users/register and
register a few more. The end result will be more impressive.
Got a nice big array of users? Good! Time to turn that into a table. Replace the
contents of knownusers.thtml with the following.
Listing 17. Creating a table
<table>
<?php
echo $html->tableHeaders(array_keys($knownusers[0]['User']));
foreach ($knownusers as $thisuser)
{
echo $html->tableCells($thisuser['User']);
}
?>
</table>
Getting started

The first helper will create a set of table headers from an array of data — in this
case, the list of keys for our users. The second helper will create a set of table cells,
wrapped in table row tags, from an array of data — in this case, the values for each
user.
That's it! Save it, then visit http://localhost/users/knownusers to see the results.
Figure 8. The results
By using the tableCells helper, you have eliminated the need to write your own
code to iterate through the array of user data. This is just one example of how to use
helpers to make it easier to work with HTML in CakePHP.
Form generation
Building a Web application without using forms is like milking a chicken: It's
Getting started

extremely complicated and rarely works. Well-built and maintainable forms are a
foundation to any well-built application. Given how often you will need to build forms,
it only seems natural to look for ways to make the process easier without cutting
corners.
Using helpers in the registration form
Helpers are especially useful when generating forms. You can use them to generate
the HTML for your input fields, as well as placeholders to hold validation error
messages. Using helpers to generate the form fields and error message holders for
Tor, the register view might look more like Listing 18.
Listing 18. Using helpers to generate the registration form
<p>Please fill out the form below to register an account.</p>
<?php echo $form->create('User', array('action' => 'register'));?>
<?php
echo $form->input('first_name');
echo $form->input('last_name');
echo $form->input('username');
echo $form->input('email');
echo $form->input('password');
?>
<?php echo $form->end('Register');?>
As you can see, making use of CakePHP's helpers can save you quite a bit of code
when writing basic form elements. Now let's look to make even more use of your
helpers.
Making the most of your helpers
To start getting more payoff from your helpers, you'll need to do two things: update
your users controller and introduce a little data validation.
Open controllers/users_controller.php and change your register function to match
the one in Listing 19.
Listing 19. Updating the users controller
function register()
{
if (!empty($this->data))
{
if ($this->User->save($this->data))
{
$this->Session->setFlash('Your registration information was accepted.');
}
}
}
Note that the occurrences of $this->params['form'] have changed to
$this->data.
Getting started

Now open the user model and add a little data validation (covered in detail later). For
now, modify your user model to look like the one in Listing 20.
Listing 20. Modifying your user model
<?php
{
var $name = 'User';
var $validate = array(
'username' => VALID_NOT_EMPTY,
'password' => VALID_NOT_EMPTY,
'email' => VALID_EMAIL
);
}
?>
</code>
To break this down briefly, the $validate array contains entries for validation,
consisting of a key (the form field name) and a regular expression used to evaluate
the data. It is not necessary to validate all of the form fields. In Listing 20,
last_name and first_name were left optional. CakePHP comes with several
predefined regular expressions for data validation. VALID_NOT_EMPTY is used just
to make sure the field is not empty. VALID_EMAIL is used to verify that a string
looks more or less like an e-mail address.
Now take it for a spin. Try submitting the form with no data, with one or two required
fields empty, with an invalid e-mail address. What do you see?
Figure 9. Data validation first try
Getting started

Now try it a second time with different missing data.
Figure 10. Data validation second try
Getting started

One thing you should notice is that the CakePHP is turning on and turning off your
error messages for you on the fly. Another thing you should notice is that CakePHP
is remembering and populating the values for the form fields, without you having to
do anything.
That's where the big payoff comes in. What didn't you have to do?
For one thing, you didn't have to tell the form fields to repopulate their information
from the _POST array. CakePHP did that for you. You didn't have to check each field
for an error and conditionally display each message individually. CakePHP did that
for you. You didn't have to make sure you formatted your tags into valid xhtml.
CakePHP did that for you, too.
Helper notes
Getting started

This tutorial barely scratches the surface of helpers. A whole tutorial could be written
on the subject. Learning how to use helpers well will go a long way toward helping
speed up your development in CakePHP. CakePHP includes helpers for Ajax (using
prototype.js), JavaScript, number conversion, text handling, dates, times, and more.
Review the manual (see Resources) to get more familiar with some of these helpers.
Section 5. CakePHP data validation
You now have a brief look at CakePHP data validation by putting in some basic
validation for users based on defined regular expressions. By defining your own
regular expressions for data validation, you can exercise more control over the
pass/fail criteria for individual form fields within Tor.
The Tor user model
Take another look at the user model.
Listing 21. The user model
<?php
{
var $name = 'User';
'username' => VALID_NOT_EMPTY,
'password' => VALID_NOT_EMPTY,
);
}
?>
This is a good start, but it's not enough. You'll want to make sure the field lengths
are honored and that the user name does not already exist. You will accomplish this
by defining your own regular expressions for validation and defining a function to
check the users table for a user name before saving the user.
Regular expressions (briefly)
A full discussion about how regular expressions is outside the scope of this tutorial.
The PHP Manual contains information about regular expressions in PHP and should
be reviewed before going too far in rolling your own data validation regular
expressions. See Resources for some helpful links.
A regular expression is basically a pattern of characters used for comparing one
string to another. For example, the character * in a regular expression will match
Getting started

any character, any number of times. If you don't know anything about regular
expressions, don't worry. The example below should help get you started.
Roll your own validation
CakePHP provides some built-in data validation regular expressions, including
VALID_NOT_EMPTY, VALID_NUMBER, VALID_EMAIL, and VALID_YEAR. These
constants are defined in cake/libs/validators.php and shouldn't be modified. You may
find it helpful to review them.
For the user name and password fields, you need to validate that the submitted data
is no longer than 40 characters. It is also helpful to verify that the user name and
password are at least six characters. A regular expression to match strings with a
length between six and 40 characters would look something like this:
/^.{6,40}$/.
Reading that regular expression from left to right:
• / — Marks the beginning of the regular expression
• ^ — Says from the beginning of the string
• . — Says any one character
• {6,40} — Says at least six times, but no more than 40 times
• $ — Says and the string ends
• / — Marks the end of the regular expression
So, read altogether, this regular expression says "from the beginning of the string,
one or more characters, at least six but not more than 40, and the string ends."
To put the regular expression to use (see Listing 22), replace the instances of
VALID_NOT_EMPTY with the regular expression, in single quotes (to prevent PHP
from trying to interpret any of the special characters).
Listing 22. Regular expression in PHP script
<?php
{
var $name = 'User';
'username' => '/^.{6,40}$/',
'password' => '/^.{6,40}$/',
);
}
?>
Make sure you've saved all your files, go back to http://localhost/users/register, and
try to register a user with a four-character user name. You should see something like
Getting started

Figure 11.
Figure 11. Data validation
Regular expressions are versatile, but they can't do things like tell you if a user name
has already been registered.
Taking validation further
Sometimes you can't tell if data is valid just by looking at it. For example, the user
name may be between six and 40 characters, but you will have to check the
database to see if the user name is already taken. CakePHP provides the ability to
manually mark a field as invalid. Take a look at the beforeValidate method in
Listing 23. This method would be added to the User model.
Listing 23. Validate the user name
Getting started

Good data validation is an important step in creating any secure application. As you
build the Tor application, look for opportunities to improve the data validation. Don't
be afraid to put in more data validation than this tutorial demonstrates. Never
assume your users are sending you the data you asked for. Validate everything.
CakePHP makes it easy.
Section 6. Filling in the gaps
So far, users can register for your application and see who has already registered.
The application needs some filling in. Using the skills you've learned so far, try filling
in some more functionality. Check out Part 2 for examples of the following.
Getting started

Login
The login view should gather the user login information and submit it to the users
controller. The users controller should look to see if the user is in the database and
verify that the password is correct. If the user has correctly logged in, write the user
name to session and send the user to the index action.
Hints:
• Use the built-in
$this->User->findByUsername($your_username_variable_here)
to search for the user in the database.
• Write the user's name to Session with
$this->Session->write('user',
$your_username_variable_here).
The index action
The index action should check to see if the user's name has been written to the
session. If the user's name has been written to the session, pull that information from
the database and present the user with a customized greeting. If the user has not
logged in, direct him to the login action.
Logout
The logout action should delete the user's user name from the session and
forward the user to the login action.
Bonus
Modify the register action to automatically log the user into the system and
forward the user to the index action. Modify the register and login actions to
use hashed passwords, rather than saving your passwords in the database as plain
text.
Don't worry too much if you get stuck. Part 2 provides sample solutions to these
problems. Then you'll jump right in and build out the Tor application product gallery.
Happy coding!
Section 7. Summary
Getting started

This tutorial has taught you how to install and configure CakePHP, the basics of
MVC design, how to validate user data in CakePHP, how to use CakePHP helpers,
and how to get an application up and running quickly using CakePHP. Part 2 covers
writing plug-ins for your application and using CakePHP's access-control lists
(ACLs).
Getting started

Downloads
Description Name Size Download method
Part 1 source code os-php-cake1.source.zip2KB HTTP
Information about download methods
Getting started

Resources
Learn
• Visit CakePHP.org to learn more.
• The CakePHP API has been thoroughly documented. This is the place to get
the most up-to-date documentation.
• There's a ton of information available at The Bakery, the CakePHP user
community.
• CakePHP Data Validation uses PHP Perl-compatible regular expressions.
• Read a tutorial titled "How to use regular expressions in PHP."
• Want to learn more about design patterns? Check out Design Patterns:
Elements of Reusable Object-Oriented Software , also known as the "Gang Of
Four" book.
• Check out some Source material for creating users.
• Check out Wikipedia's Model-View-Controller.
• Here is more useful background on the Model-View-Controller.
• Check out a list of software design patterns.
• Read more about Design Patterns.
• PHP.net is the central resource for PHP developers.
• Check out the "Recommended PHP reading list."
• Browse all the PHP content on developerWorks.
• Expand your PHP skills by checking out IBM developerWorks' PHP project
resources.
• To listen to interesting interviews and discussions for software developers,
check out developerWorks podcasts.
• Using a database with PHP? Check out the Zend Core for IBM, a seamless,
out-of-the-box, easy-to-install PHP development and production environment
that supports IBM DB2 V9.
• Stay current with developerWorks' Technical events and webcasts.
• Check out upcoming conferences, trade shows, webcasts, and other Events
around the world that are of interest to IBM open source developers.
• Visit the developerWorks Open source zone for extensive how-to information,
tools, and project updates to help you develop with open source technologies
and use them with IBM's products.
• Watch and learn about IBM and open source technologies and product
functions with the no-cost developerWorks On demand demos.
Getting started

Get products and technologies
• Innovate your next open source development project with IBM trial software,
available for download or on DVD.
• Download IBM product evaluation versions, and get your hands on application
development tools and middleware products from DB2®, Lotus®, Rational®,
Tivoli®, and WebSphere®.
Discuss
• Participate in developerWorks blogs and get involved in the developerWorks
community.
• Participate in the developerWorks PHP Forum: Developing PHP applications
with IBM Information Management products (DB2, IDS).
About the author
Duane O'Brien
Duane O'Brien has been a technological Swiss Army knife since the Oregon Trail
was text only. His favorite color is sushi. He has never been to the moon.
Getting started

Manual 5

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