JSON ["data","pre database"] - php

Question

So, I put my php page to connect to my android app on a hosted server (Hostgator). Now my PHP script for the JSON data seems to not be returning properly.This was working on my wamp server just fine. Example below of issue...
["data","pre database"][{"email":"thomas#wiregrass.edu","password":"test","fname":"Thomas","lname":"Cummings","phone":"5052030822","temppass":"15151","alert":"B"}]
Any ides as to what I did wrong or what is going on would be appreciated.
PHP script (might be outdated, this project is old):
<?php
$user = "ab73953_test";
$pass = "H3#ther78";
$db = "ab73953_testdb";
$out = array('data', 'pre database');
echo json_encode($out);
$db = mysqli_connect('localhost', $user, $pass, $db) or die("did not work");
$email=$_POST['username'];
$email = "thomas#wiregrass.edu"; // testing
$qry = 'SELECT * FROM users WHERE email = "'. $email .'"' ;
$result = mysqli_query($db, $qry) or die(" did not query");
$count = mysqli_num_rows($result);
$output = array();
if($count > 0){
while($row = mysqli_fetch_assoc($result))
{
$output[]=$row;
}
echo json_encode($output);
}
else
echo json_encode("Could not find user");
mysqli_close($db);
?>

Answer 1

That's not valid JSON. JSON is basically javascript: If the json you generate would be a javascript syntax error, then it's not valid json.
You have two separate echo json_encode(...) blocks, so you're producing two entirely separate/distinct json strings. Your output can only be one SINGLE json string.
e.g. [...][...] is two separate arrays that have gotten glued together. It's a javascript syntax error, therefore it's also invalid json. If you had something like
$arr1 = array(...);
$arr2 = array(...);
echo json_encode(array($arr1, $arr2));
you'd end up with
[[...],[...]]
and be ok
But you have
echo json_encode($arr1);
echo json_encode($arr2);
and end up with
[...][...]
which is an outright syntax error.
And note that you're vulnerable to sql injection attacks.