More elegant way of dealing with query string variables - php

Question

The site I am building is a configurator that lets you choose the color of certain items. It will have functionality to share your color config. What it will do is generate a URL with a query string, like ?plate=red&cup=blue&napkin=white My code reads the query string and changes the <img> src value. For example...
<?php
//This stuff is just grabbing the query string values...
$url = "http://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";
$querystring = parse_url($url);
parse_str($querystring['query'], $color);
$availableColors = array("red","blue","white");
?>
This is my HTML where I'm using PHP to put in the query string color values. This code is also checking to make sure the color is in an array of the available colors.
<div data-color="<?php if( in_array($color['plate'],$availableColors) ) {echo $color['plate'];} ?>">
<img src="img/tablesetting/<?php if( in_array($color['dinnerPlate'],$availableColors) ) {echo $color['plate']."_plate.png";} else {echo "dummy.gif";} ?>">
</div>
<div data-color="<?php if( in_array($color['napkin'],$availableColors) ) {echo $color['napkin'];} ?>">
<img src="img/tablesetting/<?php if( in_array($color['napkin'],$availableColors) ) {echo $color['napkin']."_napkin.png";} else {echo "dummy.gif";} ?>">
</div>
<div data-color="<?php if( in_array($color['cup'],$availableColors) ) {echo $color['cup'];} ?>">
<img src="img/tablesetting/<?php if( in_array($color['cup'],$availableColors) ) {echo $color['cup']."_cup.png";} else {echo "dummy.gif";} ?>">
</div>
What I'd like to do is avoid having a conditional statement every time I want to check if the color value is in my array availableColors. I guess just a more concise/elegant way of doing this is what I'm looking for.

Answer 1

function getColorData($color, $type) {
$result = array('color_name' => '', 'color_img' = 'dummy.gif');
$available_colors = array('red', 'blue', 'green');
if (in_array($color, $available_colors))
$result = array('color_name' => $color, 'color_img' = $color . '_' . $type . '.png');
return $result
}
Usage example:
$plate_color_data = getColorData($color['plate'], 'plate');
echo '<pre>',print_r($plate_color_data),'/<pre>'; // just for test)
<div data-color="<?=$plate_color_data['color_name']?>">
<img src="img/tablesetting/<?=$plate_color_data['color_img']?>">
</div>

Answer 2

First off, is there a reason you are using parse_url....can't just just grab the variables via $_GET or $_REQUEST?
Secondly, if you want to validate your data in_array is a good approach. A simple thing to clean things up is to simply move it all to your php area and then simply output the post-validated data to the html.
If I were building this I would run all this stuff from a database so you would query to database if a color was valid.
I would also consider generating the graphics server side via imagick or gd.