1 Environment Variables
<html><head><title> Environment Variables </title>
</head><body>
<h3>Environment variables script</h3>
<p> Here are the CGI environment variables that
this PHP script has been called with
<p><hr>
<?php
foreach($_SERVER as $key => $value) {
echo ($key . "=" . $value ."<br>");
}
?>
<h4>How to use just one environment variable:</h4>
<?php
echo "\$_SERVER['REMOTE_ADDR'] = ". $_SERVER['REMOTE_ADDR'];
?>
1.1 Exercises
1) Try the script.
2) Use one of the PHP scripts that you have created earlier in this
semester and that responds to a form. Include a print statement in the PHP script that
prints the environment variables REQUEST_METHOD, QUERY_STRING
and CONTENT_LENGTH. Note: that some of these are only available if the
method for sending the form is "get", others are only available if the
method is "post". (Check the
<form action=... method=... > tag in your form.)
REQUEST_METHOD and CONTENT_LENGTH can be used to
increase the security of your script. CONTENT_LENGTH
should not be longer than a predefined maximum length.
2 Customize Pages with PHP
PHP can show different pages to different users depending on user preferences.
2.1 Exercises
3) Ask a user to input their name into a textfield and
to choose a color from a popup menu. Then display a page with
a short message (e.g. "Thank you $_REQUEST['name'] for your request") in that color.