get posterous site_id, php (either preg_match or json_decode?) = no joy

Question

I'm trying to get a user's site_id from posterous. This data seems to be nowhere in the user's profile, and nothing in the FAQ or help or docs indicates how to find this. The only method I can find is to request a list of sites over API, So, that's what I'm trying to do, and I get back a json response, and, indeed, the site_id of any site the user has on posterous is in there, and I just want to output this.

First I tried with (where $result is the json response)

$siteid = preg_match('"site_id": \d+', $result);
echo $siteid;

I get nothing.

Then I tried with

json_decode($result);
echo $result->site_id;

I still get nothing.

I can see, in the json response ($result),

"site_id": $somenumber;

Why can't I extract this data with either preg_match or json_decode? Is there another, better method?

My full code is pasted at http://tonybaldwin.me/paste/index.php?3u

Answer 1

The Posterous list-of-sites API returns a list (as you might expect) of mappings. Thus, what you need to do is first pick the right item of the list, and then read it's id key.

$result = json_decode($response);
$first_result = $result[0];
$first_result_id = $first_result["id"];
echo $first_result_id;