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);
}