php - json_decode returns JSON_ERROR_SYNTAX but online formatter says the JSON is OK

Question

I got a very strange problem.

I have a JSON webservice.

When i check it with this website http://www.freeformatter.com/json-formatter.html#ad-output

Everything is OK.

But when i load my JSON with this code :

  $data = file_get_contents('http://www.mywebservice');

if(!empty($data))
{

    $obj = json_decode($data);

 switch (json_last_error()) {
    case JSON_ERROR_NONE:
        echo ' - JSON_ERROR_NONE';
    break;
    case JSON_ERROR_DEPTH:
        echo ' - JSON_ERROR_DEPTH';
    break;
    case JSON_ERROR_STATE_MISMATCH:
        echo ' - JSON_ERROR_STATE_MISMATCH';
    break;
    case JSON_ERROR_CTRL_CHAR:
        echo ' -  JSON_ERROR_CTRL_CHAR';
    break;
    case JSON_ERROR_SYNTAX:
        echo "

 - SYNTAX ERROR 

";
    break;
    case JSON_ERROR_UTF8:
        echo ' - JSON_ERROR_UTF8';
    break;
    default:
        echo ' - Unknown erro';
    break;
}

I got the error : SYNTAX ERROR

WHICH IS NOT HELP FULL AT ALL.

It is a nightmare.

I see that with PHP 5.5 i could use this function : http://php.net/manual/en/function.json-last-error-msg.php

(but i did not succeed to install PHP 5.5 yet, and i m not sure this function will give me more detail)

Answer 1

I faced the same issue, actually there are some hidden characters unseen and you need to remove it. Here's a global code that works for many cases:

<?php
$checkLogin = file_get_contents("http://yourwebsite.com/JsonData");

// This will remove unwanted characters.
// Check http://www.php.net/chr for details
for ($i = 0; $i <= 31; ++$i) { 
    $checkLogin = str_replace(chr($i), "", $checkLogin); 
}
$checkLogin = str_replace(chr(127), "", $checkLogin);

// This is the most common part
// Some file begins with 'efbbbf' to mark the beginning of the file. (binary level)
// here we detect it and we remove it, basically it's the first 3 characters 
if (0 === strpos(bin2hex($checkLogin), 'efbbbf')) {
   $checkLogin = substr($checkLogin, 3);
}

$checkLogin = json_decode( $checkLogin );
print_r($checkLogin);
?>