How to "POST" data in an xml file, and then display it after receiving at the other end

Question

I am trying to get used to using cURL, and have hit a wall. Currently I have two php scripts, a "sender" hosted on one site and a "receiver" hosted under a different domain on a totally different site. I want the sender to read in an xml file saved in a folder, and post it to the receiver. Then when I load the receiver page, I want to see the contents of the xml displayed on screen.

Here is my code so far.

SENDER.

     //Load the xml file, into an object called $message.

     if(file_exists('../XML/example.xml')) {
        $message = simplexml_load_file('../XML/example.xml');
     }
     else
     {
        exit ('Could not load the xml file from the specified path location');
   }

      //POST the data using cURL to the receiving page.
      $url = "http://dev.somewhere_else.com/receiver.php";  //destination
      $ch = curl_init();
      curl_setopt($ch, CURLOPT_URL, $url);
      curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
      curl_setopt($ch, CURLOPT_POST, 1);
      curl_setopt($ch, CURLOPT_POSTFIELDS, $message);
      $output = curl_exec($ch);

      curl_close($ch);
      echo $output;

      // The output gets generated and looks like an array

eg:

array(4) { ["@attributes"]=> string(5) "Array" ["header_section"]=> string(23) " " ["application_section"]=> string(18) " " ["name"]=> string(7) "example" }

So far so good? In theory this means the response via cURL is the expected data. However when I go to the other site and load the receiving page, instead of seeing something similar I get.....

          array(0) { }

          result = 

RECEIVER.

      // Display the contents of the super global..
      var_dump($_POST);          

This displays "array(0) {}" here on this page. I suspect because the data is xml, and so $_POST isn't populated. Puzzling though, as the response the sender gets display's correctly. To fix this I added..

       $dataFromPost = file_get_contents('php://input');
       echo"<br><br>result =";
       echo $dataFromPost;

So these last three lines should read the incoming stream from my "sender" and put it in the $dataFromPost variable. It should then display it on the screen, but all i get is blank...

I've read countless examples and followed many different guides, but can't get it to work the way I expect it to. Can anyone please put me out of my misery?

Answer 1

You are setting the post fields incorrectly. Typically, you would want to pass an array with CURLOPT_POSTFIELDS like so:

curl_setopt($ch, CURLOPT_POSTFIELDS, array('message' => $message));

or even better by building a query string with http_build_query():

curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query(array('message' => $message)));

The PHP manual also describes a way of posting the entire file with this setting:

The full data to post in a HTTP "POST" operation. To post a file, prepend a filename with @ and use the full path. The filetype can be explicitly specified by following the filename with the type in the format ';type=mimetype'. This parameter 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. As of PHP 5.2.0, value must be an array if files are passed to this option with the @ prefix. As of PHP 5.5.0, the @ prefix is deprecated and files can be sent using CURLFile. The @ prefix can be disabled for safe passing of values beginning with @ by setting the CURLOPT_SAFE_UPLOAD option to TRUE.

You should then be able to receive the data from $_POST however you decide to send it.

Answer 2

I have not tried the following solution but You can try

Sender code Make a JSON string of your object

$post_data['xmlobj'] = json_encode($message) //or u can use` serialize/unserialize 

pass the post data array in your request

curl_setopt($ch, CURLOPT_POSTFIELDS, $post_data);

Reciever Code.

at the recieving point get Post array use json_decode get the object_string from post array and decode it

$obj = json_decode($_POST['xmlobj']); // if you are using serialize then use unserialize here.

NOTE:

1. if you are using json_decode you will get stdclass obje
2. if you are using unserialize then you will get simplexmlobj

Answer 3

Like we found out in the comments, the script itself seems to work as you are getting the processed XML like you mentioned here:

// The output gets generated and looks like an array eg: array(4) { ["@attributes"]=> string(5) "Array" ["header_section"]=> string(23) " " ["application_section"]=> string(18) " " ["name"]=> string(7) "example" }

So I think you are just missunderstood the POST so I would recommend you to take a look at the manual for $_POST. You already suspected that something is different than you probably thought and you are correct with this.

Just some good and simple information about post:

• POST requests are never cached
• POST requests do not remain in the browser history
• POST requests cannot be bookmarked

Here you can find additional info:

• How PHP Works
• HTTP Methods: GET vs. POST
• Zend: PHP 101

So in your case, you have to save the XML. I don't know what is your intention to do, but here is a small approach:

Just take the XML from the cURL request, save it in file with file_put_contents() and add a condition (if isset post[your key] then file write else show file) to you site or split the files, one which shows only the output and one which takes your request and renews the XML.

I made this (post[your key]) bold, because you have to secure it at least a bit, otherwise I have just to post to your page and it will change.

Note without SSL it is not really possible to secure your requests, but you can at least use some key in your post to validate that this is your script, where the post comes from.

Additional information:

• how to secure POST method without using SSL?
• Fake a $_POST via PHP

To get back to your question: If you post something you can see the content of the post with your var_dump() in the receiver file, If you navigate in your browser to that file $_POST is empty, because of the reason you have not postet anything, you just created a GET request. I don´t want to confuse you but the GET request method has (usually) nothing to do with the PHP $_GET variable => HTTP Request Methods