I'm trying to convert an array to XML but I am failing to get it 100% correct

Question

I need to output the response from the database in XML. So far I have gotten it to output this:

The outermost tag needs to match the name of the action query, it'll either be <courses> or <students>.

Here is my code:

<?php
require_once('./database.php');

if (isset($_GET['format'])) {
    $format = filter_var($_GET['format']);
}

if (isset($_GET['action'])) {
    $action = filter_var($_GET['action'], FILTER_SANITIZE_STRING);
    $tableName = "sk_$action";
}

$query = "SELECT * FROM $tableName";

if (isset($_GET['course'])) {
    $course = filter_input(INPUT_GET, 'course');
    $query .= " WHERE courseID = :course";
}

function arrayToXml($arr, $i = 1, $flag = false)
{
    $sp = "";
    for ($j = 0; $j <= $i; $j++) {
        $sp .= " ";
    }
    foreach ($arr as $key => $val) {
        echo "$sp&lt;" . $key . "&gt;";
        if ($i == 1) echo "\n";
        if (is_array($val)) {
            if (!$flag) {
                echo "\n";
            }
            arrayToXml($val, $i + 5);
            echo "$sp&lt;/" . $key . "&gt;\n";
        } else {
            echo "$val" . "&lt;/" . $key . "&gt;\n";
        }
    }

}

$statement = $db->prepare($query);
$statement->bindValue(':course', $course);
$statement->execute();

$response = $statement->fetchAll(PDO::FETCH_ASSOC);

$statement->closeCursor();

if ($format == 'json') {
    echo json_encode($response);
}
if ($format == 'xml') {
    arrayToXml($response, 1, true);
}

I'm pretty new to PHP and have never worked with XML. All help is appreciated. Thanks.

Oh my gosh please don't format XML by doing string concatenation. You're sure to write invalid XML. There are several [XML extensions in PHP](http://php.net/manual/en/refs.xml.php) to choose from. — Bill Karwin, Mar 05 '19 at 01:59
I'll try anything at this point, been beating my head against this for a while. I literally tried MOST of the answers that this question got marked as a duplicate as and it either renders nothing or much of the same I have above. I'm not good enough with PHP to parse the docs and figure this out, unfortunately. — MMelvin0581, Mar 05 '19 at 02:02

score 3 · Accepted Answer · answered Mar 05 '19 at 02:36

function arrayToXml($arr, $collectionTag, $singleTag) {
    $collection = new SimpleXMLElement("<$collectionTag/>");
    foreach ($arr as $row) {
        $element = $root->addChild($singleTag);
        foreach ($row as $tag => $value) {
            $element->addChild($tag, $value);
        }
    }
    return $collection;
}

$courses = arrayToXml($response, 'courses', 'course');

echo $courses->asXML();

Tested with PHP 7.1.23. Output:

<?xml version="1.0"?>
<courses>
 <course><courseID>cs601</courseID><courseName>Web Application Development</courseName></course>
 <course><courseId>cs602</courseId><courseName>Server-Side Application Development</courseName></course>
 <course><courseId>cs701</courseId><courseName>Rich Internet Application Development</courseName></course>
</courses>

(I added newlines because by default it doesn't add any.)

I'm trying to convert an array to XML but I am failing to get it 100% correct

1 Answers1