<?php
// INIT CURL
$ch = curl_init();

// SET URL FOR THE POST FORM LOGIN
curl_setopt($ch, CURLOPT_URL, 'http://www.external-site.com/Members/Login.php');

// ENABLE HTTP POST
curl_setopt ($ch, CURLOPT_POST, 1);

// SET POST PARAMETERS : FORM VALUES FOR EACH FIELD
curl_setopt ($ch, CURLOPT_POSTFIELDS, 'fieldname1=fieldvalue1&fieldname2=fieldvalue2');

// IMITATE CLASSIC BROWSER'S BEHAVIOUR : HANDLE COOKIES
curl_setopt ($ch, CURLOPT_COOKIEJAR, 'cookie.txt');

# Setting CURLOPT_RETURNTRANSFER variable to 1 will force cURL
# not to print out the results of its query.
# Instead, it will return the results as a string return value
# from curl_exec() instead of the usual true/false.
curl_setopt ($ch, CURLOPT_RETURNTRANSFER, 1);

// EXECUTE 1st REQUEST (FORM LOGIN)
$store = curl_exec ($ch);

// SET FILE TO DOWNLOAD
curl_setopt($ch, CURLOPT_URL, 'http://www.external-site.com/Members/Downloads/AnnualReport.pdf');

// EXECUTE 2nd REQUEST (FILE DOWNLOAD)
$content = curl_exec ($ch);

// CLOSE CURL
curl_close ($ch);

?>