How do I parse an XML file from a POST variable in PHP?

Question

I have written a script that posts an XML request to my server. See below:

$xml_request='<?xml version="1.0"?><request><data></data></request>';
$url='http://www.myserver.com/xml_request.php';

//Initialize handle and set options

$ch = curl_init(); 
curl_setopt($ch, CURLOPT_URL, $url); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
curl_setopt($ch, CURLOPT_TIMEOUT, 4); 
curl_setopt($ch, CURLOPT_POSTFIELDS, $xml_request); 
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Connection: close'));

$result = curl_exec($ch); 

curl_close($ch);

Now I'm trying to figure out how to parse that request on the server side. If I do a simple

print_r($_POST);

it returns:

Array
(
    [<?xml_version] => \"1.0\"?><request><data></data></request>
)

which doesn't seem right. I want to be able to pass the post into one of the XML parsers - most likely simplexml_load_string(), so I need access to the clean XML file. How do I access the POST request so I get a clean file?

Answer 1

The problem is with the script that posts the request. You need to encode the XML string before you send it to the server in order to prevent the server from parsing it. Try running your XML through rawurlencode before you post it to the server.

---

Looking into this more, I saw another problem. It looks like the CURLOPT_POSTFIELDS option expects you to form the string yourself. Quoth the manual page (bold is mine):

The full data to post in a HTTP "POST" operation. To post a file, prepend a filename with @ and use the full path. This can either be passed as a urlencoded string like 'para1=val1&para2=val2&...' or as an array with the field name as key and field data as value. If value is an array, the Content-Type header will be set to multipart/form-data.

So in your case, it would be something like

curl_setopt($ch, CURLOPT_POSTFIELDS, 'xmlstring='.rawurlencode($xml_request))

And then in your receiving script, you'd expect to be able to access it as $_POST['xmlstring'].