JSON - Avoid UNICODE conversion - php

Question

Why is my string converted to UNICODE in JSON?
http://example.com/test/test.php?MyComment=%C4%93
Saved in JSON as {"MyComment":"\u0113 "}
I want to be saved as {"MyComment":"%C4%93"}
PHP:
$MyComment = $_GET["MyComment"];
print_r($MyComment); //%C4%93
$results = array ( array(
"MyComment" => $MyComment,
));
$inp = file_get_contents('Test.json');
$arr = json_decode($inp);
$results = array_merge($results, $arr);
$fp_login = fopen('Test.json', w);
fwrite($fp_login, json_encode($results));
fclose($fp_login);

Answer 1

If you just want to have the urlencoded value, you have to replace this:
$MyComment = $_GET["MyComment"];
with this (updated due to the comments below):
$MyComment = urlencode( $_GET["MyComment"] );
For your Swift problem you should use :
$MyComment = rawurlencode( $_GET["MyComment"] );
The whitespace will be encoded as %20 so you can decode it at the Swift side.
console output:
Object {MyComment: "%C4%93"}

Answer 2

You have to pass the constant JSON_UNESCAPED_UNICODE to avoid it.
$json = json_encode($data, JSON_UNESCAPED_UNICODE);

Answer 3

In php 5.4+, php's json_encode does have the JSON_UNESCAPED_UNICODE option for plain output. On older php versions, you can roll out your own JSON encoder that does not encode non-ASCII characters.