Lorna Mitchell has taken a look at using JSON in PHP applications in a new post to her blog. More specifically, she looks at how to get it working and a downfall or two that comes with it.

This is a quick outline on working with JSON from PHP, which is actually pretty simple to do. This post has some examples on how to do it and what the results should look like. JSON stands for JavaScript Object Notation, and is widely used in many languages (not just JavaScript) for serialisation. It is particularly popular for use in web services.

She gives an example of the translation between a PHP array (of subarrays) out into a JSON message complete with grouping. She does mention one problem that using this data format has, though - the lack of typing information that comes along with the message details. That can mean the difference between an array being pushed in on the sending side and an object (from json_decode) coming out the other side. As noted in the comments, though, there's a second parameter for json_decode that tells it to force the output as an array instead (along with a mention of another helpful constant in PHP 5.3 - JSON_FORCE_OBJECT).