JSON_Decode() Returns Null Issues

PHP json_decode() returns NULL with seemingly valid JSON?

This error means that your JSON string is not valid JSON!

Enable throwing exceptions when an error happens and PHP will throw an exception with the reason for why it failed.

Use this:

$json = json_decode($string, null, 512, JSON_THROW_ON_ERROR);

Php - json_decode returns null

<?php
$data='{
    "id": "1",
    "fields": [{
        "id": "1",
        "value": "asdasd"
    }, {
        "id": "2",
        "value": "asdasd"
    }, {
        "id": "3",
        "value": "asdasd"
    }]
}';

$dataNew=json_decode($data,true);
echo '<pre>';
    print_r($dataNew);

Your json was not valid. The json-keys need to be inside double-quotes. After that json_decode will work fine.

Output is:

Array
(
    [id] => 1
    [fields] => Array
        (
            [0] => Array
                (
                    [id] => 1
                    [value] => asdasd
                )

            [1] => Array
                (
                    [id] => 2
                    [value] => asdasd
                )

            [2] => Array
                (
                    [id] => 3
                    [value] => asdasd
                )

        )

)

json_decode returns NULL after webservice call

EDIT:
Just did some quick inspection of the string provided by the OP. The small "character" in front of the curly brace is a UTF-8 B(yte) O(rder) M(ark) 0xEF 0xBB 0xBF. I don't know why this byte sequence is displayed as here.

Essentially the system you aquire the data from sends it encoded in UTF-8 with a BOM preceding the data. You should remove the first three bytes from the string before you throw it into json_decode() (a substr($string, 3) will do).

string(62) "{"action":"set","user":"123123123123","status":"OK"}"
            ^
            |
            This is the UTF-8 BOM

As Kuroki Kaze discovered, this character surely is the reason why json_decode fails. The string in its given form is not correctly a JSON formated structure (see RFC 4627)

json_decode() returns null, even though file_get_contents() works perfectly, even though json is valid

You can do it like:

//storing json contents in a variable.
$json_contents = file_get_contents('../../Datafiles/allThreads.txt');

//decode json
$currentThreadasList = json_decode($json_contents, TRUE)

Edit-1:

Have you tried the following:

$currentThreadasList = json_decode(file_get_contents('../../Datafiles/allThreads.txt'), TRUE);

json_decode returns null and bool false

$json = preg_replace('/[[:cntrl:]]/', '', $json); $array = json_decode($json, true);

I should preg_replace before decoding JSON