Game-Jaming/Backend/Controllers/FileHandler/GetGameData.php

<?php
require_once "../../../bootstrap.php";
use \Backend\Models\GameData;
use \Backend\Models\Group;

if(isset($_GET['gameDataId'])){
    $openGameDataStream =  GameData::find($_GET['gameDataId']);
}elseif(isset($_GET['groupId'])){
    $openGameDataStream = Group::find($_GET['groupId'])->GameData();
}elseif (isset($_GET['gameJamId'])){
    $gameDataIds = Group::where("game_jam_id",$_GET['gameJamId'])->pluck("game_data_id")->toArray();
    $openGameDataStream = GameData::whereIn("id", $gameDataIds)->get();
}else{
    $openGameDataStream = GameData::all();
}

header("Access-Control-Allow-Methods: GET");
header("Access-Control-Allow-Headers: X-Requested-With, Content-Type, Accept");
header('Content-Type: application/json;charset=UTF-8');
echo json_encode(array('data' => $openGameDataStream->jsonSerialize()));