json_decode() Not Working in PHP?

Posted in Code, Tips and Tricks

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This took me a few minutes today to work out and find an answer on Google so I thought I’d share it.

I had a string that I was posting from a form and while Firebug on the client said that the string was valid, on the server side PHP’s json_decode() function was returning me a NULL indicating invalid JSON. I spit out the string using good old var_dump() and I could see straight away that I would need to strip some slashes from it, but I couldn’t figure out why.

I don’t like to simply know how to fix something, I like to know why it was broken in the first place! A bit of Googling gave me the answer, it turned out to be because of the magic_quotes setting in PHP.

Instead of just wrapping everything in a stripslashes() call I decided to write a wrapper function that will take into account whether magic_quotes is on or off. It will also allow me to do whatever I want later one if I wanted to parse a particular type of data or something.

Here is the code. As you can see it’s nothing fancy, but it works and hopefully it saves people some time.

function _json_decode($string) {
	if (get_magic_quotes_gpc()) {
		$string = stripslashes($string);
	}

	return json_decode($string);
}

27 Comments

Declan

Dec 31, 2008

Excellent – this has saved me some time. I was having trouble working out why a json_encoded object could not then be immediately json_decoded.
Manny Calavera

Feb 4, 2009

You are the MAN! I’ve spent a lot of time trying to figure out why json_decode was working great on my local server but once moved to my webserver it kept coming out NULL.

Thank you!
Miklós Kriván

Feb 10, 2009

Thanks for this simple but excellent help :-)
I had big headache this night. But now it works again :-)

God bless you!
Henrik Petersson

Feb 20, 2009

Magic quotes are evil, can’t imagine why anyone would leave it on by default.

Thanks for the info. I switched PHP distribution (to entropy) for my local server and couldn’t figure out why json_encode stopped working. Turned out magic quotes was turned on. *shudders*
JM

Feb 23, 2009

Muchas gracias amigo !
tim

Mar 19, 2009

Thank you a lot, this fixed my site!
Jaime

Jun 23, 2009

Thanks dude, after an hour googling you gave me the correct answer… :)
menslow

Jul 24, 2009

Yes! Thank you!! I owe you a beer next time I’m in Perth.
Arthur Kay

Aug 24, 2009

This has taken me hours to figure out, and I’ve utter more swear words at this damn thing than I care to admit.

Problem solved. Thanks for posting this!
Gordon

Jan 10, 2010

Hi, Thanks for this post. I’ve been scratching my head for the afternoon on this one, a piece of code using json_decode() was working on my local server but not when I put it online.
Greg

Jan 11, 2010

just a little modification :)

function _json_decode($string, $flag = false) {
if (get_magic_quotes_gpc()) {
$string = stripslashes($string);
}

return json_decode($string, $flag);
}
Mark

Feb 26, 2010

You da man! I don’t enjoy debugging AJAX, and this saved my butt.
Justin

Mar 8, 2010

Awesome! Thanks for preventing me from banging my head.
kulish

Mar 11, 2010

thanks dear, its really helpfull…
James Beaule

Mar 24, 2010

You wouldnt believe how long ive been searching for something like this. Browsed through 5 pages of Yahoo results couldnt find diddly squat. Quick search on bing. There this is…. Really have to start using it more often!
Mazeb

Apr 24, 2010

Thx a lot man that was giving me a headache i knew it was something related to the server but couldn’t figure out what. And now it works like a charm
Kashish

Jun 30, 2010

Hey,
Thank you very very much.I was very stuck up with that problem as I am new to php.Searched a lot but coudn’t make out.Your code helped me a lot.Thank you once again.
virtualme123

Aug 13, 2010

Thanks Aaron, this was a great help. Was racking my brain for a while on this issue.
ZIOM

Sep 14, 2010

DUDE>< THANKS< LOVE U DAAAAMN
David

Oct 10, 2010

Thanks a lot man, it really helps
Joost

Oct 12, 2010

Thanks! Helped me out today :-)
gurunathan

Jan 24, 2011

$notes = json_decode($data);
$handle = fopen(‘patients/in_file.txt’, ‘r’);

$notes1 = json_decode(fgets($handle));

fclose($handle);

both fgets($handle) and $data has the same value

[{"ID":1,"LEFT":"70.87087087087087","TOP":"22.8","WIDTH":"4.804804804804805","HEIGHT":"3.2","DATE":{"Y":"2011","M":"01","D":"23","H":"22","I":"42"},"NOTE":"dsfs","AUTHOR":"","LINK":"","COLOR":"orange"}]

but $notes return NULL, where $notes1 returns Array ( [0] => stdClass Object ( [ID] => 1 [LEFT] => 70.87087087087087 [TOP] => 22.8 [WIDTH] => 4.804804804804805 [HEIGHT] => 3.2 [DATE] => stdClass Object ( [Y] => 2011 [M] => 01 [D] => 23 [H] => 22 [I] => 42 ) [NOTE] => dsfs [AUTHOR] => [LINK] => [COLOR] => orange ) ).

Please do help..

I tried your solution. But the issue not solved.
Steve

Feb 22, 2011

Thanks very very much,
Finding this solution has saved me from hours of frustration!!

Thanks Again!!!
same

Jun 28, 2011

same here. stupid magic quotes.
AHUOO

Sep 28, 2011

cool, thanks for your sharing.
Khayer

Oct 10, 2011

It save me from my client bullet !!!!! Than you very much..
Rachana

Dec 15, 2011

Hey mate! Thanks for sharing. This help me a lot.