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Question

I am trying to retrieve a list of items from a mySQL db and insert them as a list in a select object on a webpage. The following is the bit of code that isnt working.

In the first line, I am trying to retrieve a JSON object from a public function called getBrands() in a singleton object I have created called DatabaseInterface.

The second line is then attempting to turn that JSON object into a php array.

Finally, I am running a loop which can option each item in between tags for the webpage.

Where am I going wrong?

<?php 

var $brandArrayJSON = DatabaseInterface::getBrands();
$brandArray = JSON_decode($brandArrayJSON);

for ($loop=0; $loop < sizeof($brandArray); $loop++) {
    echo "<option>$brandArray[$loop]</option>";
}

?>

EDIT: In case it helps, here is my DatabaseInterface singleton. I have included this file at the top of my php file

class databaseInterface {

private static $_instance;

// Private constructor prevents instantiation
private function __construct() {
}

public static function getInstance() {
    if (!self::$_instance) {
        self::$_instance = mysqli_connect(self::databaseHost, self::databaseUsername, self::databasePassword, self::databaseName);
        if (mysqli_connect_errno(self::$_instance)) {
            throw new Exception("Failed to connect to MySQL:" . mysqli_connect_error());
        }
    }
    return self::$_instance;
}

public function getBrands() {

    try {
        $con = DatabaseInterface::getInstance();
    } catch (Exception $e) {
        // Handle exception
        echo $e->getMessage();
    }

    $query = "SELECT psBrandName from brands";
    $result = mysqli_query($con, $query) or die ("Couldn't execute query. ".mysqli_error($con));

    $resultArray[] = array();

    while ($row = mysqli_fetch_assoc($result)) {

        extract($row);
        $resultArray[] = $psBrandName;

    }

    return json_Encode($resultArray);

}

Answer 1

There is nothing "wrong" with the code, in that it should work (provided nothing is broken on the query-side). However, there are several things that should be improved.

First, basically what the getBrands() method is doing is equivalent to this:

$brandArray = json_encode(array('test','test2','test3'));
echo $brandArray; // returns ["test","test2","test3"]

Now, when you decode that you get the same thing you originally put in (an array):

$brandArray = json_decode('["test","test2","test3"]');
var_dump($brandArray); // Will dump an array

Since this is an array (not a PHP object), you can just use a foreach.

foreach($brandArray as $option) {
    echo '<option>', $option, '</option>';
}

If you're worried about it being an object in some instances (maybe you had a non-array JS object which would be mostly the equivalent to a PHP associative array), you could cast the json_decode result into an array.

$brandArray = (array)$brandArray;

Now, in your getBrands() method, I would highly recommend just using $row['psBrandName'] instead of cluttering things up with extract, unless you have a really good reason to do this.