Load iFrame contents via CURL request? - php

Question

I have an application that includes a file (FileX.php) which under certain conditions, will echo an iFrame to the screen which loads a tracking URL (FileY.php). In a production environment where I directly include FileX.php into the main page (FileA.php), the iFrame gets echoed to the screen and FileY.php is successfully called.
In testing though, I need to call multiple versions of FileA.php which each include FileX.php which outputs the iFrame to call FileY.php. I am automating this large number of requests using cURL requests.
When loading FileA.php through a cURL request, it successfully does the include() of FileX.php but because it is happening through cURL, the iFrame never loads it's destination (FileY.php).
The cURL request for fileA looks something like this:
TestFile.php
// URL
$url = "http://www.example.com/FileA.php";
// New Cookie file
$ckfile = tempnam("/tmp", "CURLCOOKIE");
// New Connection
$ch = curl_init();
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt ($ch, CURLOPT_COOKIEJAR, $ckfile);
curl_setopt ($ch, CURLOPT_COOKIEFILE, $ckfile);
curl_setopt($ch, CURLOPT_COOKIESESSION, 0);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($ch, CURLOPT_URL, $url);
curl_exec($ch);
curl_close($ch);
FileA.php:
include_once('FileX.php');
FileX.php:
echo("<iframe src='http://www.example.com/FileY.php' width='0' height='0'></iframe>");
FileY.php
// Contains logging stuff to log the fact that FileY.php was called.
Like I said, if I call FileA.php directly in my browser, FileX.php is included and FileY.php is loaded in the iFrame successfully. When I call FileA.php via cURL the iFrame doesn't load and FileY.php is never called.
I've tried wrapping the echo() in FileX.php with ob_start() and ob_end_flush() to force the output but that didn't work. I've tried adding a sleep(1) in case maybe the request was happening too fast, no luck.
Is there a cURL option I can change to allow this to occur? I can't figure out why it won't load the iFrame src.

Answer 1

Ah, so it turns out I was using an option incorrectly.
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
This should actually be false or 0. When using true or 1, all output is caught and returned via the cURL request rather than being output. So it should be:
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 0);