PHP sends an empty Response Payload instead of JSON - php

Question

Sorry if I'm not good at formulating questions or if this isn't a good question, but I've been trying for days and getting no progress on this and I'm ready to effing cry. Please, please help.
So this PHP file:
<?php
header("Content-Type: application/json; charset=UTF-8");
$obj = json_decode($_GET["x"], true);
$conn = new mysqli("localhost", "user", "password", "database");
$i = 1;
$message = array();
while ($i < 31){
$query = $conn->prepare("SELECT dag, maand, jaar, timeslot FROM boeker WHERE dag = $i AND maand = ? AND jaar = ?");
$query->bind_param('ii', $obj["monthQ"], $obj["yearQ"]);
$query->execute();
$result = $query->get_result();
$outp = $result->fetch_all(MYSQLI_ASSOC);
$message = array();
if(empty($result)){
//available
} else if ($result["timeslot"] == null){
array_push($message, "occupied", $i);
} else {
array_push($message, $result["timeslot"], $i);
}
$i++;
}
$package = json_encode($message);
echo $package;
?>
is getting this request:
https://url/file.php?x='{"monthQ":10,"yearQ":2021}'
and the reply is an empty Response Payload, which throws an error, because it can't be JSON.parsed
I would think that $message, even when the array stays empty, would make $package a simple [], which should parse...
Is something wrong with my PHP?
Thanks for any help!

Answer 1

You need to remove the single quotes around the json string in your url. If you have no control over constructing that url, you can just run:
$obj = json_decode(trim($_GET['x'],"'"), true);
I've tested that, and it works.
If you do have control over constructing that url, I recommend that you remove the single quotes AND urlencode the json block.

Answer 2

Leaving breadcrumbs after solving a similar problem here. My php.ini file had a max_post_size set to 2K and I was sending a POST request with size >2K. PHP decided to sweep the problem under the rug and proceed with the request with an empty body.