Form Processing In Php

PHP – Form Processing in PHP Harit Kothari [email_address]

Agenda

Reading data from a page

$_REQUEST, $_GET & $_POST

Isset() & array_key_exists()

Validating data

Reading data from a page

HTML Forms

Use of text box, text area, radio button, check box

Data (inserted or selected as per above objects) can be sent either of 2 ways – GET or POST request

So, a request is like a box, in which selected items are packed and sent

Practical Applications

You are developing a web based form to collect user data

User fills data and when Submit button is pressed, the data should be inserted in database, or something like that

User login management

$_REQUEST

Represents HTTP request as an array

Is automatically created when a Get or POST is made, superset of $_GET & $_POST

Also contains $_COOKIES array

Request type can be checked by: $_SERVER['REQUEST_METHOD'] It should return either 'GET' or 'POST'

See an example next

$_REQUEST Example

Assuming that some data has been sent via a form. It can be interpreted in PHP as under: <?php if ($_SERVER['REQUEST_METHOD'] == 'GET') { echo “This is a get request”; } else echo “This is a post request”; // extract values from $_REQUEST // uName & pWord areTextBoxs in HTML $username = $_REQUEST['uName']; $password = $_REQUEST['pWord']; ?>

$_GET

Parameters are appended to URL

Less secure

URL length limitation

See an example next

$_GET Example

If you are accepting name and age from a form, you can give output like following: Welcome <?php echo $_GET["name"]; ?>.<br /> You are <?php echo $_GET["age"]; ?> years old!

$_POST

Parameters are encoded as request body

More secure

No length limitation

Mostly used

See an example next

$_POST Example

If you are accepting name and age from a form, you can give output like following: Welcome <?php echo $_GET["name"]; ?>.<br /> You are <?php echo $_GET["age"]; ?> years old!

So, what's the difference? - apparently that, it includes name & age parameters in request body!

isset()

Check a particular variable is set or not

Typically used to check existance, and so to give respective error message if the value is required

Example : if(isset($name) == true) echo “name entered”; else echo “please enter your name”;

array_key_exists()

Similar to isset(), checks if value exists in array

Initially known as key_exists()

if (array_key_exists(key, array)) { ... }

Example : if (array_key_exists('name', $person)) echo "name entered"; else echo "please enter your name";

Validating data

User input via form, as we have seen

Accept data, check its validity and report to the user

How? See next!

Example 1 - simple

index.htm <html> <body> <form name =”test_form1” method = “POST” action = “form_process.php”> <p/>User Name <input type = “text” name = “name”/> <br/><p>User Name <input type = “text” name = “age”/> <br><input type = “submit” value = “Validate Me”/> </form> <body> </html>

form_process.php <?php $name = $_POST['name']; $age = $_POST['age']; // validity of age $valid_age = strspn($age, "1234567890") == strlen($age); // above can be achieved also, as under: // $valid_age = preg_match('/^d+$/', $age); if(!isset($name)) die(“Name is not given!”); if(!$valid_age) die(“Age is invalid”); ?>

Example 2 – Self Processing

<html> <body> <form action="<?= $PHP_SELF ?>" method="POST"> Name: <input type=text name="name" value="<?= $name ?>" /><br /> Status: <input type="checkbox" name="status" value="active" <?php if($status == 'active') { echo 'checked'; } ?> /> Active<br/> Media: <select name="media_type"> <option value="">Choose one</option> <option value="picture" <?php media_selected('picture') ?> />Picture</optio <option value="audio" <?php media_selected('audio') ?> />Audio</option> <option value="movie" <?php media_selected('movie') ?> />Movie</option> </select><br /> File: <input type="text" name="filename" value="<?= $filename ?>" /><br />Caption: <textarea name="caption"><?= $caption ? ></textarea><br />

<input type="hidden" name="tried" value="yes" /> <input type="submit" value="<?php echo $tried ? 'Continue' : 'Create'; ? >" /> </form> </body> </html>

<?php $name = $_POST['name']; $media_type = $_POST['media_type']; $filename = $_POST['filename']; $caption = $_POST['caption']; $tried = ($_POST['tried'] == 'yes'); if ($tried) { $validated = (!empty($name) && !empty($media_type) && ! empty($filename)); if (!$validated) { ?> <p> The name, media type, and filename are required fields. Please fill them out to continue. </p> <?php }

} if ($tried && $validated) { echo '<p>The item has been created.</p>'; } // was this type of media selected? print "selected" if so function media_selected ($type) { global $media_type; if ($media_type == $type) { echo "selected"; } } ?>

Whats next?