Whitelist json and php

Question

I am making a userid whitelist in php and json but it wont work so it should be like this

{ "users": { "ANID": { "ANID": "true" }, 
"97594568": { "isvalid": "true" }, 
"ANID": { "isvalid": "true" }, 
"ANID": { "isvalid": "true" }, 
"ANID": { "isvalid": "true" }, 
"ANID": { "isvalid": "true" }, 
"ANID": { "isvalid": "true" } } } 

and if you go to whitelist.php?uid=ANID it should say succes and if not whitelisted it should say Failed

Answer 1

Use array_key_exists:

whitelist.json:

{
  "users": {
    "0001": {
      "isvalid": "true"
    },
    "0002": {
      "isvalid": "true"
    },
    "0003": {
      "isvalid": "true"
    },
    "0004": {
      "isvalid": "true"
    },
    "0005": {
      "isvalid": "true"
    }
  }
}

whitelist.php

<?php

$data = file_get_contents('whitelist.json');
$json = json_decode($data, true);

if (array_key_exists($_GET['uid'], $json['users'])) {
    echo 'User is whitelisted';
} else {
    echo 'User is NOT whitelisted';
}

whitelist.php?uid=0001 would return User is whitelisted

whitelist.php?uid=0006 would return User is NOT whitelisted