PHP: Various outcomes based on radio selections

Question

I have this script, which works perfectly well. BUT I will end up creating hundreds of variations if I keep doing it this way.

    <?php

$q1 = $_GET["q1"];
$q2 = $_GET["q2"];
$q3 = $_GET["q3"];
$q4 = $_GET["q4"];


if ( $q1 == "a" && $q2 == "a" && $q3 == "a" && $q4 == "a" ) {
    header("Location: http://www.mostly-a.co.uk");
    exit;    
}

if ( $q1 == "b" && $q2 == "b" && $q3 == "b" && $q4 == "b" ) {
    header("Location: http://www.mostly-b.co.uk");
    exit;    
}

?>

Basically I need the script to echo 1 of 5 possible urls based on which answers are given

So for example, "url-mostly-a" would be echo'd if the user selected: aaaa aaab aaba abaa baaa aaac aaca acaa caaa

etc etc.....

Answer 1

4 lines should do it:

$count = array_count_values($_GET);
arsort($count);
$answers = array_keys($count);
header("Location: http://www.mostly-{$answers[0]}.co.uk");

1. count values occurences
2. reverse sorting of values
3. get an array with the keys (still sorted)
4. use first value of array

Answer 2

If you understood correctly, what you need first is to find the most common value in array $_GET.

For that you need to get a count of duplicates:

array_count_values($_GET);

Then iterate and find the biggest value.

---

Edit:

Then you might be able to use this to get the key "name" with the biggest value:

$arrayCnt = array_count_values($_GET);
$theKey = array_search(max($arrayCnt), $arrayCnt)

Answer 3

Are searching for something like this?:

foreach(array(
    'a' => 'http://aaaaaa...', 
    'b' => 'http:/bbbb',
    // ...
as $check => $url) {
    if($q1 == $check && $q2 == $check && $q3 == $check && $q4 == $check) {
        header("Location: $url");
    }
}

Answer 4

The following is a working code-example. It validated the input and as you can see, input validation is a a large part of any script.

// configuration

$qsValidKeys  = ['q1' => 0, 'q2' => 0, 'q3' => 0, 'q4' => 0];
$qValidValues = ['a', 'b', 'c', 'd'];

// input

$qsGet = array_intersect_key($_GET, $qsValidKeys);

if (!$qsGet) {
    trigger_error('No input given.');
    return;
}

$qsFiltered = [];

foreach ($qsGet as $key => $value) {
    if (in_array($value, $qValidValues, true)) {
        $qsFiltered[$key] = $value;
    } else {
        trigger_error(sprintf('Invalid Input value for "%s".', $key));
    }
}

if (!$qsFiltered) {
    trigger_error('No input given (filtered).');
    return;
}

// processing

$count = array_count_values($qsFiltered);
arsort($count);
$topAnswer = array_keys($count)[0];
$location = sprintf("http://www.mostly-%s.co.uk", $topAnswer);

Answer 5

Thanks M8R-1jmw5r,

I looked into what it all meant and get the basic grasp of it all so thanks for that! The very last part didn't seem to be working though so I changed it too:

$location = printf('Click <a href="http://www.open.ac.uk/'.'%s'.'/">here</a> to view your results', $topAnswer);

This now seems to work perfectly well, I hope its still secure enough!