schouk schouk - 9 days ago 6
JSON Question

json_decode returns NULL after webservice call

There is a strange behaviour with

json_encode
and
json_decode
and I can't find a solution:

My php application calls a php web service. The webservice returns json that looks like this:

var_dump($foo):
string(62) "{"action":"set","user":"123123123123","status":"OK"}"


now I like to decode the json in my application:

$data = json_decode($foo, true)


but it returns
NULL
:

var_dump($data):
NULL


I use php5.
The Content-Type of the response from the webservice:
"text/html; charset=utf-8"
(also tried to use
"application/json; charset=utf-8"
)

What could be the reason?

Answer

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)

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