PHP: Get POST JSON

By  on  

My recent work at Mozilla has me creating an OAuth-like authentication transaction between Bugzilla and Phabricator.  This task has thrust me back into the world of PHP, a language I haven't touched much (since version ~5.2) outside of creating WordPress themes and plugins for this blog.  Coming back to a language you haven't touched in years feels like a completely new experience; you notice patterns and methods that you wouldn't have guessed of in years past.

Part of the authentication transaction requires Phabricator to receive a POST request that contains JSON data.  I had expected the data to land in $_POST but the variable was empty; how the hell do I get the POST data?  To get POST JSON with PHP, you use the following:

# Get JSON as a string
$json_str = file_get_contents('php://input');

# Get as an object
$json_obj = json_decode($json_str);

file_get_contents, which I though was only used to retrieve content from local files or traditional URLs, allows you to use the special php://input address to retrieve JSON data as a string.  From there you use json_decode to turn the JSON string into a workable object/array.

It makes sense that the JSON isn't handled via normal $_POST since there's really no key, per se; essentially you just need the "blob" of data as a whole, which is provided by php://input.  You can test the JSON+POST handling with cURL.

Recent Features

  • By
    From Webcam to Animated GIF: the Secret Behind chat.meatspac.es!

    My team mate Edna Piranha is not only an awesome hacker; she's also a fantastic philosopher! Communication and online interactions is a subject that has kept her mind busy for a long time, and it has also resulted in a bunch of interesting experimental projects...

  • By
    Regular Expressions for the Rest of Us

    Sooner or later you'll run across a regular expression. With their cryptic syntax, confusing documentation and massive learning curve, most developers settle for copying and pasting them from StackOverflow and hoping they work. But what if you could decode regular expressions and harness their power? In...

Incredible Demos

  • By
    Animated AJAX Record Deletion Using jQuery

    I'm a huge fan of WordPress' method of individual article deletion. You click the delete link, the menu item animates red, and the item disappears. Here's how to achieve that functionality with jQuery JavaScript. The PHP - Content & Header The following snippet goes at the...

  • By
    MooTools History Plugin

    One of the reasons I love AJAX technology so much is because it allows us to avoid unnecessary page loads.  Why download the header, footer, and other static data multiple times if that specific data never changes?  It's a waste of time, processing, and bandwidth.  Unfortunately...

Discussion

  1. Lorenzo

    I always use this line of code:

    @json_decode(($stream = fopen('php://input', 'r')) !== false ? stream_get_contents($stream) : "{}");

    It does not throw a warning in case there’s no request body, and simply fallback to an empty object instead of null.

  2. @David, you might want to merge $_POST and 'php://input'

    $_POST = array_merge($_POST, (array) json_decode(file_get_contents('php://input')));

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!