Share the same cookie between two PHP requests with cURL - php

Question

My first post here... I am handling cookies between get/post pair of requests.
Based on this other question:
share the same cookie between two website using PHP cURL extension
Is my approach correct?
<?php
//set POST variables
$referer = 'http://www.correios.com.br/encomendas/prazo/';
$url = 'http://www.correios.com.br/encomendas/prazo/prazo.cfm';
$fields = array(
'Altura' => '8',
'Comprimento' => '16',
'Formato' => '1',
'Largura' => '15',
'MaoPropria' => 'N',
'avisoRecebimento' => 'N',
'cepDestino' => '99999999',
'cepOrigem' => '99999999',
'data' => '02/12/2012',
'dataAtual' => '02/12/2012',
'embalagem' => '',
'peso' => '1',
'resposta paginaCorreios'=> '',
'servico' => '99999',
'valorD' => '',
'valorDeclarado'=> ''
);
//url-ify the data for the POST
foreach($fields as $key=>$value) { $fields_string .= $key.'='.$value.'&'; }
rtrim($fields_string, '&');
//open connection
$ch = curl_init();
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_HEADER, false);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($ch, CURLOPT_TIMEOUT, '10');
curl_setopt($ch, CURLOPT_AUTOREFERER, true);
curl_setopt($ch, CURLOPT_COOKIEJAR, '/tmp/cookies.txt');
curl_setopt($ch, CURLOPT_COOKIEFILE, '/tmp/cookies.txt');
// Post 1
curl_setopt($ch, CURLOPT_HTTPGET, true);
curl_setopt($ch, CURLOPT_URL, $referer);
$result = trim(curl_exec($ch));
//
$ch = curl_init($url);
//Post 2
curl_setopt($ch,CURLOPT_URL, $url);
curl_setopt($ch,CURLOPT_POST, count($fields));
curl_setopt($ch,CURLOPT_POSTFIELDS, $fields_string);
curl_setopt($ch, CURLOPT_REFERER, $referer);
//execute post
$result = curl_exec($ch);
//
//close connection
curl_close($ch);
echo($result);
?>
What I need is mimic this behavior:
Response Headers:
Content-Type text/html; charset=ISO-8859-1
Date Sun, 02 Dec 2012 20:13:08 GMT
Server Microsoft-IIS/7.5
Set-Cookie JSESSIONID=c6308c7edb989a54edef1b656119101c321b;path=/ CFGLOBALS=urltoken%3DCFID%23%3D33736896%26CFTOKEN%23%3D28355865%26jsessionid%23%3Dc6308c7edb989a54edef1b656119101c321b%23lastvisit%3D%7Bts%20%272012%2D12%2D02%2018%3A13%3A09%27%7D%23timecreated%3D%7Bts%20%272012%2D12%2D02%2002%3A13%3A29%27%7D%23hitcount%3D6%23cftoken%3D28355865%23cfid%3D33736896%23;expires=Tue, 25-Nov-2042 20:13:09 GMT;path=/
Transfer-Encoding chunked
Request Headers:
Accept text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding gzip, deflate
Accept-Language pt-BR,pt;q=0.8,en-US;q=0.5,en;q=0.3
Connection keep-alive
Cookie CFID=33736896; CFTOKEN=28355865; CFGLOBALS=urltoken%3DCFID%23%3D33736896%26CFTOKEN%23%3D28355865%26jsessionid%23%3D983074629e3d7344ff534b12637b7f127163%23lastvisit%3D%7Bts%20%272012%2D12%2D02%2002%3A56%3A48%27%7D%23timecreated%3D%7Bts%20%272012%2D12%2D02%2002%3A13%3A29%27%7D%23hitcount%3D5%23cftoken%3D28355865%23cfid%3D33736896%23
Host www.correios.com.br
User-Agent Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:17.0) Gecko/20100101 Firefox/17.0
Reading from some others topics, I have learned about multi_exec:
PHP cURL multi_exec delay between requests
I mean, what is the correct approach for the this task?
Thanks in advance!
Renato