Not storing POST data (json) - php

Question

I have this bit of javascript:
var jsonString = "some string of json";
$.post('proxy.php', { data : jsonString }, function(response) {
var print = response;
alert(print);
and this bit of PHP (in proxy.php):
$json = $_POST['json'];
//set POST variables, THIS IS WHERE I WANT TO POST TO!
$url = 'http://my.site.com/post';
//open connection
$ch = curl_init();
//set the url, number of POST vars, POST data
curl_setopt($ch,CURLOPT_URL, $url);
curl_setopt($ch,CURLOPT_POST, 1);
curl_setopt($ch,CURLOPT_POSTFIELDS, "data=" . urlencode($json));
//execute post (the result will be something like {"result":1,"error":"","pic":"43248234af832048","code":"234920348239048"})
$result = curl_exec($ch);
$response = json_decode($result);
$imageHref = 'http://my.site.com/render?picid=' . $response['picid'];
//close connection
curl_close($ch);
echo $imageHref;
I am trying to post data to an external site using a proxy. From there, I append the picid that the site responds with and append it to the URL to get the image URL.
Am I missing something here? I am not getting anything in response and it seems like my data is not even being posted (when I try echo $json after the first line in proxy.php, I get an empty string). Why am I not able to echo the JSON? Is my implementation correct?
Thanks!

Answer 1

In your Javascript code, you are using this :
{ data : jsonString }
So, from your PHP code, should you not be reading from $_POST['data'], instead of $_POST['json'] ?
If necessary, you can use var_dump() to see what's in $_POST :
var_dump($_POST);
Edit after the comment : if you are getting a JSON result such as this :
{"result":1,"error":"","pic":"43248234af832048","code":"234920348239048"}
This is a JSON object -- which means, after decoding it, you should access it as an object in PHP :
$response = json_decode($result);
echo $response->pic;
Note : I don't see a picid element in that object -- maybe you should instead use pic ?
Here too, though, you might want to use var_dump(), to see how your data looks like :
var_dump($response);

Answer 2

try this:
$json = $_POST['data'];
or even better do
var_dump($_POST);
to see what is actually in your post when you start