Full PHP application / 4 layer model - start here

Designing PHP-Based Solutions: Best Practice example from a Well House Consultants training course
More on Designing PHP-Based Solutions: Best Practice [link]

This example is described in the following article(s):
   • Larger applications in PHP - [link]
   • Application design in PHP - multiple step processes - [link]
   • Improving the structure of your early PHP programs - [link]

If you're searching for a page where you can try this code, select here

This example references the following resources:
http://www.wellho.net/course/ph.html)

Source code: 4lm_top.php Module: H115


<?php

/* If you're writing a full application (perhaps a number
of them!) in PHP, you'll want it to be easy to write, easy
to maintain, easy to modify, and robust and consistend for
the user.  Using the "4 layer model" will help you achieve
these aims - you'll write each piece of logic only once,
keep it encapsulated in simple functions that you can easily
test and amend, and share between applications.

The four layers are:
1. The Web helper functions
2. The business logic
3. The template (look at feel) of the page(s)
4. The top layer - this file - that pulls it all together

Our PHP programming course (http://www.wellho.net/course/ph.html)
covers this 4 layer model and gives you an opportunity to try
it out - tailoring our shell to provide a simple but complete
application.  This file - like all other source on our courses -
is available for free download on the Internet and you are
welcome to make use of it if you wish. However, to make the
best of it we stongly advise to come along to the training;
there is a limit to just how much of a manual we can write in
here in order to tell you how it all fits together! */

#----------------------------------------------------

# Globals!

$includepath = "." ;
# for demo, include files in current dir

# $includepath = "$_SERVER[DOCUMENT_ROOT]/../demoprivate";
# for a practical installation - use something like

$sessname = "rupert";
# unique identifier to keep session apps apart

#----------------------------------------------------

# Load in the web helpers and business logic
include ("$includepath/4lm_webhelpers.inc");
include ("$includepath/4lm_business.inc");

// Shell for general purpose session based application

session_name($sessname);
session_start();

// Set up for a new session if needed

if (! $_SESSION[current]) {
        $_SESSION[current] = 0;
        }

// Provide a reset capability for use during testing
if ($_REQUEST[reset]) {
        $_SESSION = array();
        $_SESSION[current] = 0;
        }

######################### Handler responses from previous form

$error = 0; # Global flag for error handling in validation functions
$alert = array(); # Array of alerts for next form
$fill = array(); # Array of elements to fill in to template

switch ($_SESSION[current]) {

case 0: // Finish up from initialisation
        $_SESSION[current] = 1;
        break;

case 1: // Finish up from first form
        // (In sample app - ask for name and email)
        checkphase1();
        break;

case 2: // Finish up from second form
        // (In sample app - ask for phone number and postcode)
        checkphase2();
        break;

default:
        print "Oh dear - bust!";
        break;
}

/* At this point, call up any general business logic
that should be run between reading in the previous form
and providing the next form */

$fill[current] = $_SESSION[current];
$fill[phases] = 3;
$fill[copyright] = "Well House Consultants, ".date("Y");

######################### Prepare for next form

switch ($_SESSION[current]) {

case 1: // prepare for phase 1 (name and email in sample)
        prepphase1();
        break;

case 2: // prepare for phase 2 (phone and postal)
        prepphase2();
        break;

case 3: // Confirm data, "Thank You" page and store to database
        prepphase3();
        session_destroy(); // Avoid echo being re-submitted
        break;

default:
        print "Oh dear - failed!";
        break;
}
######################### Send response

$fill[errmsg] = $error ?
        "<b>Error - please correct as indicated</b><br />" :
        "";
$html = filltemplate("$includepath/4lm_template.htp");
print $html;

?>

Learn about this subject

This module and example are covered on the following public courses:
* Deploying LAMP - Linux, Apache, MySQL, Perl/PHP
* Linux Web Server
* Learning to program in PHP
* PHP Programming
* Intermediate PHP - weekend course / hobby / club / leisure users
* PHP Programming
* Learning to program in PHP
Also available on on site courses for larger groups

Books covering this topic

Yes. We have over 700 books in our library. Books covering PHP are listed here and when you've selected a relevant book we'll link you on to Amazon to order.

Other Examples

This example comes from our "Designing PHP-Based Solutions: Best Practice" training module. You'll find a description of the topic and some other closely related examples on the "Designing PHP-Based Solutions: Best Practice" module index page.

Full description of the source code

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