cURL and Drupal: Storing Remote Cookies Per User - php

Question

I've got a web application in Drupal that is basically acting as a proxy to a multi-page HTML form somewhere else. I am able to retrieve the page with cURL and parse it with DOMDocument, then embed the contents of the <form> inside a Drupal form:
<?php
function proxy_get_dom($url, $method = 'get', $arguments = array()) {
// Keep a static cURL resource for speed.
static $web = NULL;
if (!is_resource($web)) {
$web = curl_init();
// Don't include any HTTP headers in the output.
curl_setopt($web, CURLOPT_HEADER, FALSE);
// Return the result as a string instead of echoing directly.
curl_setopt($web, CURLOPT_RETURNTRANSFER, TRUE);
}
// Add any GET arguments directly to the URL.
if ($method == 'get' && !empty($arguments)) {
$url .= '?' . http_build_arguments($arguments, 'n', '&');
}
curl_setopt($web, CURLOPT_URL, $url);
// Include POST data.
if ($method == 'post' && !empty($arguments)) {
curl_setopt($web, CURLOPT_POST, TRUE);
curl_setopt($web, CURLOPT_POSTFIELDS, http_build_query($arguments));
}
else {
curl_setopt($web, CURLOPT_POST, FALSE);
}
$use_errors = libxml_use_internal_errors(TRUE);
try {
$dom = new DOMDocument();
$dom->loadHTML(curl_exec($web));
}
catch (Exception $e) {
// Error handling...
return NULL;
}
if (!isset($dom)) {
// Error handling...
return NULL;
}
libxml_use_internal_errors($use_errors);
return $dom;
}
function FORM_ID($form, &$form_state) {
// Set the initial URL if it hasn't already been set.
if (!isset($form_state['remote_url'])) {
$form_state['remote_url'] = 'http://www.example.com/form.faces';
}
// Get the DOMDocument
$dom = proxy_get_dom($form_state['remote_url'], 'post', $_POST);
if (!isset($dom)) {
return $form;
}
// Pull out the <form> and insert it into $form['embedded'].
$nlist = $dom->getElementsByTagName('form');
// assert that $nlist->length == 1
$form['embedded']['#markup'] = '';
foreach ($nlist->item(0)->childNodes as $childnode) {
// It would be better to use $dom->saveHTML but it does not accept the
// $node parameter until php 5.3.6, which we are not guaranteed to be
// using.
$form['embedded']['#markup'] .= $dom->saveXML($childnode);
}
// Apply some of the attributes from the <form> element onto our <form>
// element.
if (isset($element->attributes)) {
foreach ($nlist->item(0)->attributes as $attr) {
if ($attr->nodeName == 'action') {
$form_state['remote_action'] = $attr->nodeValue;
}
elseif ($attr->nodeName == 'class') {
$form['#attributes']['class'] = explode(' ', $attr->nodeValue);
}
elseif ($attr->nodeName != 'method') {
$form['#attributes'][$attr->nodeName] = $attr->nodeValue;
}
}
}
return $form;
}
function FORM_ID_submit($form, &$form_state) {
// Use the remote_action as the remote_url, if set.
if (isset($form_state['remote_action'])) {
$form_state['remote_url'] = $form_state['remote_action'];
}
// Rebuilt the form.
$form_state['rebuild'] = TRUE;
}
?>
However, the embedded form will not move past the first step. The issue seems to be that the page behind the proxy is setting a session cookie which I am ignoring in the above code. I can store the cookies with CURLOPT_COOKIEFILE and CURLOPT_COOKIEJAR, but I'm not sure where the file should be. For one thing it should definitely be a different location for each user, and it definitely should not be a publicly accessible location.
My question is: How do I store and send cookies from cURL per-user in Drupal?

Answer 1

Assuming you're using sessions, then use the user's session ID to name the cookie files. e.g.
curl_setopt(CURLOPT_COOKIEFILE, 'cookies.txt');
would give EVERYONE the same cookie file and they'll end up sharing the same cookie. But doing
curl_setopt(CURLOPT_COOKIEFILE, 'cookie-' . session_id() . '.txt');
will produce a unique session file for every user. You will have to manually remove that file, otherwise you're going to end up with a HUGE cookie filer repository. And if you're changing session ID's (e.g. session_regenerate_id(), you'll "lose" the cookie file because the session ID's won't be the same anymore.