Lab 7: PHP Validation

Validate user input with PHP and regular expressions

Most often, web pages use HTML forms for user input. It is very important to validate user input before storing it in a database or other types of processing

On lab7input.php web page, use an XHTML Form with input widgets to allow the user to
- Enter their name (Required. restrict input to letters or spaces, e.g. Ahmad Sami)
- Enter their company (Optional. allow anything, e.g. W3C)
- Enter their email address (Required. Validate email to match aa@bb.cc where a,b,c are any letters)
- Enter their telephone (Optional. Validate to ddd-ddd-dddd or ddd-dddd if present)
- Enter their website URL (Optional, Validate to valid URLs)
- Select their Project Type (Required. Must select HTML, CSS, PHP, or other)
- Note: to speed up the lab, use the code on this solved lab7input.php page
  - This page contains no PHP yet, but save the HTML code as lab7input.php
On lab7validate.php Web page, use PHP to validate the user input, displaying error message is there is a problem or displaying the user input if everything is correct
- Note: to speed up the lab, download and use this lab7validate.php code
- Complete the PHP function validate_input() that returns a string containing any error messages or an empty string if the user input completely validates
- A tool for testing PHP regular expressions is available online
- 60 standard validation functions is also available online

Lab 7 Screen Snapshots

Note: All HTML elements are laid out using the default browser styling. Inline elements are enclosed inside paragraphs <p>

lab7input.php
lab7 input

lab7validate.php
lab7 validate

Code all-in-one-page processing

A better approach to handling PHP user input validation is to do it all-in-one-page: user input, validation, and processing.

The overall logic to implement all-in-one-page processing is

if this page has just called itself with the user input data
validate the user input data

if the data is valid
process the data (save in db, etc.)
go to a confirmation page

else (the input data has problems)
show the error messages

Display the HTML form (re-display any previously entered user input data values so the user does not need to retype everything)

Modify lab7input.php to do all-in-one-page processing: prompt for input, validate, and process the data (minimally)

Copy and paste your function validate_input() into the start of lab7input.php
Change the action attribute of the PHP form to call itself (action="")
Add the if else logic to take all-in-one-page approach to processing (Code given below)

<?php
// if this page has just called itself with user input data
// (i.e. the user pressed the submit button)
if (isset($_POST['submitButton'])) {

// validate the user input data
$error_messages = validate_input();

// if user input is valid, process the data and go to confirmation page
if ($error_messages == "") {
$_SESSION['name'] = $_POST['name']; // simplified processing
header('Location: thankyou.php'); // go to confirmation page
exit();
}
else {
echo "<p>$error_messages</p>"; // show the error messages
}
}
?>

Use Session Variables

The simplified processing of the data above is to save the user's name as a session variable to re-display on the confirmation page: thankyou.php

To use session variables on the lab machines, we need to reset the session save path to C:\wamp\www\labs\sessiondata (as well as creating the subfolder sessiondata)

Add calls to the session_save_path and session_start php functions to the beginning of lab7input.php

<?php
session_save_path ($_SERVER['DOCUMENT_ROOT'] . "/sessiondata/");
session_start();
?>

Create a short thankyou.php page that displays the welcome message: Thank you name, getting name from the SESSION variable set in lab7input.php

Make previously entered user data re-display in form elements

In order to re-show the form with user input still present, use the input element's value attribute set to the contents of the appropriate $_POST variable. For example,

<input id="name" name="name" type="text" value="<?php echo $_POST['name']; ?>" />;