Returning JSON from a PHP function - php

Question

I want to transform this PHP function.. that should return JSON data.
<?php
$query = 'SELECT * FROM `' . mix_player::table() . '` a';
if (isset($_GET['cat']) || isset($_GET['order']))
if (isset($_GET['cat'])) {
$query .= ' INNER JOIN `' . mix_player::table_cat_rel() . '` b '
. "ON (a.`id` = b.`idtrack`) WHERE `idcat` = '" . $wpdb->escape($_GET['cat']) . "'";
$random = $wpdb->get_var('SELECT `random`, `order` FROM `' . mix_player::table_categories() . "` WHERE `id` = '"
. $wpdb->escape($_GET['cat']) . "'");
if (!$random)
$order = $wpdb->get_var(NULL, 1);
}
if (isset($_GET['order']))
$order = $_GET['order'];
if ($order != '') {
if (isset($_GET['cat']))
$query .= ' AND ';
else
$query .= ' WHERE ';
$tracks = mix_player::order_list($query, $order);
}
} else {
$random = '0';
}
$query .= ' ORDER BY `id` ASC';
if (isset($tracks) || ($tracks = $wpdb->get_results($query, ARRAY_A))) {
// option "shuffle = true" not always working into mix. Do it our own way...
if ($random == 1) { // shuffle tracks?
list($usec, $sec) = explode(' ', microtime());
mt_srand((float) $sec + ((float) $usec * 100000));
$nrows = count($tracks);
for ($i = 0; $i < $nrows; $i++) {
$j = mt_rand(0, $nrows - 1); // pick j at random
$row = $tracks[$i]; // swap i, j
$tracks[$i] = $tracks[$j];
$tracks[$j] = $row;
}
}
foreach ($tracks as $row) {
$artist = (mix_player::entities($row['artist']));
echo ($artist);
$title = (mix_player::entities($row['title']));
echo ($title);
$url =(xspf_player::entities($row['url']));
echo ($url);
}
}
?>
to display like this json file :
{"title":"title", "artist":"artist","media":"url media.mp3","color":"#56B0E8" },
Can you help me?
Thanks in advance.

Answer 1

You can simply create an array and populate it with your desired values, then return it as JSON:
function tracks2json( $tracks )
{
$retval = array();
foreach( $tracks as $row )
{
$array = array();
$array['artist'] = mix_player::entities($row['artist']);
$array['title'] = mix_player::entities($row['title']);
$array['media'] = 'url '.xspf_player::entities($row['url']);
$array['color'] = '#56B0E8';
$retval[] = $array;
}
return json_encode( $retval );
}
if( isset($tracks) || ($tracks = $wpdb->get_results($query, ARRAY_A)) )
{
// Your MySQL routine here
$json = tracks2json( $tracks );
}

Answer 2

echo json_encode(array("title"=>$title,"artist"=>$artist,"url"=>$url));