Question

I have a gzipped base64 JSON string, after converting this string json_decode() can’t decode it. I think it is an encoding issue, but have been unable to resolve it.

I am running PHP 5.2 which doesn’t support json_last_error().

Does anyone know what is going on here?

<?php 
$gzipped_base64 = "7b0HYBxJliUmL23Ke39K9UrX4HShCIBgEyTYkEAQ7MGIzeaS7B1pRyMpqyqBymVWZV1mFkDM7Z28995777333nvvvfe6O51OJ/ff/z9cZmQBbPbOStrJniGAqsgfP358Hz8ifvGv8dGv8frXaH+N7NeY/hpvf40vf43LXyP/Nepf4/zXKH+N6te4ou8e0f9f0e/4tqHff8mv8f8A";

$json = gzinflate(base64_decode($gzipped_base64));

echo $json; // prints: {"StackOverflow":"Rocks"}

$array = json_decode($json, true);

echo var_dump($array); // prints: NULL
?>

Answer 1

json_decode expects the input to be UTF-8 encoded but your data seems to be encoded with UTF-16:

var_export($json);

The output is:

'{' . "\0" . '"' . "\0" . 'S' . "\0" . 't' . "\0" . 'a' . "\0" . 'c' . "\0" . 'k' . "\0" . 'O' . "\0" . 'v' . "\0" . 'e' . "\0" . 'r' . "\0" . 'f' . "\0" . 'l' . "\0" . 'o' . "\0" . 'w' . "\0" . '"' . "\0" . ':' . "\0" . '"' . "\0" . 'R' . "\0" . 'o' . "\0" . 'c' . "\0" . 'k' . "\0" . 's' . "\0" . '"' . "\0" . '}' . "\0" . ''

So convert the character encoding using mb_convert_encoding or iconv to convert to UTF-8 before calling json_decode.