[SOLVED] How to get the referer from remote file_get

How to get the referer from remote file_get_contents

I set a PHP script that output JSON like the following:

<?php
 // ref.php
print json_encode(array('ref' => $_SERVER["HTTP_REFERER"]), JSON_UNESCAPED_SLASHES);
?>

The above code is all the code in that file. From another file I tried to read the output as follows:

<?php
// ref_index.php
$json = file_get_contents('http://localhost/4test/ref.php'); 
$data = json_decode($json);
var_dump($data);
?>

The above code returns NULL because the ref.php failed to get the $_SERVER["HTTP_REFERER"] value, so when I replace $_SERVER["HTTP_REFERER"] with any fixed value, such as 'blahh blahh` it returns json object.

My question is: How could I get the referral of file_get_contents() i.e the url that it runs from to get data from my application.

Solution

The referrer is transferred using the Origin header in HTTP. You would need to set that header in your file_get_contents() call. To achieve this, you would need to use a customized stream context using stream_context_create() and pass that as the third param to file_get_contents():

$opts = array(
  'http'=>array(
    'method'=>"GET",
    'header'=>"Origin: SET REFERRER URL HERE"
  )
);

echo file_get_contents(
    'http://localhost/4test/ref.php',
    false,
    stream_context_create($opts)
);