PHP Request.QueryString - $_GET with conditions not sure how to

Question

I am not familiar with php and want to write a redirect script using php (The server I am working on does not support asp)

I think it needs to be something like this

<?php if ($_GET[id]; == 'test') {echo '<meta http-equiv="refresh" content="0;URL=http://www.test.com" />'} ?>

I want to send a query string like http://www.domain.com?id=test then the page should redirect to http://www.test.com or a query like http://www.domain.com?id=example and it shoud redirect to http://www.theexamplesite.com

Using javascript and classic asp I would have done it like this:

<% if (Request.QueryString("id") == 'test') { %><meta http-equiv="refresh" content="0;URL=http://www.test.com" /><% } %>
<% if (Request.QueryString("id") == 'example') { %><meta http-equiv="refresh" content="0;URL=http://www.theexamplesite.com" /><% } %>

Hope you can help me!

Thanks

Geoffrey Bachelet · Accepted Answer · 2010-12-28 19:05:09Z

5

<?php

$targets = array(
  'test'    => 'http://www.test.com/',
  'example' => 'http://www.theexamplesite.com/',
);

if (isset($_GET['id']) && isset($targets[$_GET['id']]))
{
  header('Location: '.$targets[$_GET['id']]);
  exit;
}

That way you have a good view of your configured redirects and are able to add / remove / update them easily !

edited Dec 28, 2010 at 19:05

answered Dec 28, 2010 at 13:33

Geoffrey Bachelet

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4 Comments

Felix Kling Over a year ago

Nice, but you should check whether $_GET['id'] is set too!

Gerald Ferreira Over a year ago

I Like this solution best as it shows me the variables easily! - Thanks to ALL

Gerald Ferreira Over a year ago

Is it possible to open the site in a new window like target="_blank"

Geoffrey Bachelet Over a year ago

@Gerald no you can't, since all we're doing here is sending an HTTP header to the browser (nor could you using the meta html tag btw)

Felix Kling · Accepted Answer · 2010-12-28 13:34:24Z

3

You have a syntax error. It should be:

if ($_GET['id'] == 'test')

But for the actual redirect, you might want to use header:

if(array_key_exists('id', $_GET) {
    if($_GET['id'] === 'test') {
        header('Location: http://www.test.com');
    }
    else if($_GET['id'] === 'example') {
        header('Location: http://www.theexamplesite.com');
    }
}

Reference: array_key_exists

edited Dec 28, 2010 at 13:34

answered Dec 28, 2010 at 13:23

Felix Kling

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6 Comments

Felix Kling Over a year ago

@Wookai: Thanks, I just was about to fix it :D

Gerald Ferreira Over a year ago

Thanks a million - I did this so far <?php if ($_GET['id'] == 'site') echo '<meta http-equiv="refresh" content="0;URL=site.com" />' ?> <?php if ($_GET['id'] == 'site1') echo '<meta http-equiv="refresh" content="0;URL=site1.com" />' ?> and it seems to work

Felix Kling Over a year ago

@Gerald Ferreira: Yep, but using header is the cleaner way I would say.

Gerald Ferreira Over a year ago

I will test your solution just now as it looks more elegant!

mario Over a year ago

The array_key_exists is unnecessary bloat here. First, a $_GET["id"] can be an empty string or NULL at worst. Hence key presence testing is dumb, an isset() is sufficient. But PHP also is a dynamic and weakly typed language, an unset/NULL value will be interpreted as empty string or false. You only need isset if you keep debugging notices enabled on your production server.

|

user432219 · Accepted Answer · 2010-12-28 13:26:55Z

1

You can simply write:

<?php

if ($_GET[id] == 'test') {
    header('Location: http://www.test.com');
}
else {
    // real output
}

?>

answered Dec 28, 2010 at 13:26

user432219

Comments

Ed Manet · Accepted Answer · 2010-12-28 13:27:49Z

1

This just looks like a target for exploitation. Make sure you do some validation on the value of $_GET['id'] before you start redirecting the users. If someone does http://www.domain.com?id=http://www.maliciouswebsite.com, will your script take them there?

Just be careful with redirects and do a lot of input validation.

answered Dec 28, 2010 at 13:27

Ed Manet

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1 Comment

Gerald Ferreira Over a year ago

It should not I think: I am writing this to hide affiliate links to not pass Page Rank to the sites I am promoting: the id will equal a value that I pre setup: If value = 1 redirect to site 1 if value 2 redirect to site 2 - so if you put malicious site it is not defined and should not work

Salman Arshad · Accepted Answer · 2010-12-28 13:36:59Z

1

I fail to see why were not accomplish the task given that you have ASP/JavaScript knowledge. Just tweak your asp script a little bit:

<?php
    if ($_GET["id"] == 'test')
    {
        ?>
        <meta http-equiv="refresh" content="0;URL=http://www.test.com" />
        <?php
    }
    if ($_GET["id"] == 'example')
    {
        ?>
        <meta http-equiv="refresh" content="0;URL=http://www.theexamplesite.com" />
        <?php
    }
?>

There are other constructs available to do the same job such as switch...case or the ?: operator. The ?: operator can shorten up your code quite a bit:

<meta http-equiv="refresh" content="0;URL=<?php echo $_GET['id'] == 'test' ? 'http://www.test.com' : 'http://www.theexamplesite.com'; ?>" />

answered Dec 28, 2010 at 13:36

Salman Arshad

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1 Comment

Gerald Ferreira Over a year ago

I Think I struggled with the $_GET function - Thanks for the tip

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