Why is $_POST array empty in PHP after an a request with post data

Question

I make a post request to the the page getremote.php with post data but the $_POST array seems to be empty. Would be grateful if anyone can tell me what I've done wrong.

The javascript code to make the request is

var postdata = "Content-Type: application/x-www-form-urlencoded\n\nedits=" + this.createEditXMLtext(this.editXMLstruct);
 var xmlhttp;
 if (window.XMLHttpRequest)
   {// code for IE7+, Firefox, Chrome, Opera, Safari
   xmlhttp=new XMLHttpRequest();
   }
 else
   {// code for IE6, IE5
   xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
   }
  dispmes("processing edits");
 xmlhttp.open("POST",userProfile.homeurl + "?remoteurl=" + userProfile.homeurl + "&cmdeditprofile&password=password",false);

 xmlhttp.send(postdata);

 var response = xmlhttp.responseXML;

where this.createEditXMLtext(this.editXMLstruct) simply creates a string

I haven't had this problem before and don't seem to have the same solution as other people who have posted similar problems. The php code at userProfile.homeurl + " is

header("Content-type: text/xml");
 $query = '';                  
    foreach( $_POST as $key => $value ){ 
  $query .= "$key=$value&";
 }
 echo do_post_request($_GET['remoteurl'] . $qstring,$query);

but the string $query is always empty - I checked it by adding echo $query to the bottom of the file

Are you 100% sure POST is empty? What does a print_r($_POST); yield? — Pekka
– Pekka, Commented Oct 23, 2010 at 11:22
I guess that the Header information must be separated from the body with two \r\n and not only \n. HTTP 1.1 specification: generic-message = start-line *(message-header CRLF) CRLF [ message-body ] start-line = Request-Line | Status-Line CRLF = \r\n — DrDol
– DrDol, Commented Oct 23, 2010 at 11:23
You should certainly consider going to a javascript framework like jQuery, Dojo, or YUI to handle your AJAX requests. — Mitch C
– Mitch C, Commented Oct 23, 2010 at 14:23

Paul Dixon · Accepted Answer · 2010-10-23 11:25:29Z

4

The value you pass to send() should be the entire post body, and you've included a header in it. When that body reaches PHP, it will fail to parse it as encoded form data.

Instead, set the data type by calling setRequestHeader()

 //create the postdata, taking care over the encoding
 var postdata = "edits=" + encodeURI(this.createEditXMLtext(this.editXMLstruct));

 //let server know the encoding we used for the request body
 xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");

 //and here we go 
 xmlhttp.send(postdata);

answered Oct 23, 2010 at 11:25

Paul Dixon

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Nick Craver · Accepted Answer · 2010-10-23 11:25:20Z

1

I've never seen it done this way, try setting your header separately from the POST body via XMLHttpRequest.setRequestHeader(), like this:

var postdata = "edits=" + this.createEditXMLtext(this.editXMLstruct);
var xmlhttp;
if (window.XMLHttpRequest) { // code for IE7+, Firefox, Chrome, Opera, Safari
  xmlhttp = new XMLHttpRequest();
} else { // code for IE6, IE5
  xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded")
dispmes("processing edits");
xmlhttp.open("POST", userProfile.homeurl + "?remoteurl=" + userProfile.homeurl + "&cmdeditprofile&password=password",false);
xmlhttp.send(postdata);
var response = xmlhttp.responseXML;

answered Oct 23, 2010 at 11:25

Nick Craver

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