Fixing json_encode() Problem in PHP 5.5 on Ubuntu 13.10

I upgraded to Ubuntu 13.10 over the weekend and everything went pretty well. It automatically brings PHP 5.5 with it, too. When I tried to run a web app I was working on, though, I received this message:

Fatal error: Call to undefined function json_encode()

I subsequently Googled around and came across a highly-ranked blog article which makes it sound like PHP 5.5 drops support for json_encode because of some silly licensing argument. The truth is, PHP 5.5 does NOT drop support for json_encode. For a much better and much clearer explanation, I recommend reading this article.

Now, enough of the balleyhoo! How do we fix it?

It was was easy! Install the php5-json package and restart Apache. Voilà!

sudo apt-get install php5-json
sudo /etc/init.d/apache2 restart

Note that the author of the blog article linked above mentions that re-installing the php5-dev pacakged fixed his woes. While that didn't help me, you may want to give it a try if the above didn't help you.

jQuery's getJSON

I recently had a struggle getting jQuery's $.getJSON function to work on Internet Explorer (IE6 & IE7). I tried and tried to debug the javascript, but was getting no where. After giving up for a while and coming back to it the next day, I thought of checking the target file—the file jQuery was fetching asynchronously—for problems.

It turns out that IE doesn't like JSON encoded documents that are specified as UTF-8. Not sure what the problem is, but the document has to be returned in a format IE likes. If not, IE will not allow jQuery to process it. Now, I had a header on this file that specified the content-type and charset. But, I changed it and instead I put only the content-type at the top of my JSON-returning PHP files:

<?PHP
header("Content-Type: application/json");
?>

Why does IE balk at UTF-8 specified charsets for JSON-encoded responses?? Who knows. But, from the research I've done, specifying the charset in the HTTP header is not something that is required. I am sure there are good reasons to specify the charset, but this (above) works great for me.