php如何访问https

在php中使用curl库访问https，具体方法如下：

function curlPost($url, $data = array(), $timeout = 30, $CA = true){ 
$cacert = getcwd() . '/cacert.pem'; //CA根证书 
$SSL = substr($url, 0, 8) == "https://" ? true : false; 
$ch = curl_init(); 
curl_setopt($ch, CURLOPT_URL, $url); 
curl_setopt($ch, CURLOPT_TIMEOUT, $timeout); 
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout-2); 
if ($SSL && $CA) { 
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true); // 只信任CA颁布的证书 
curl_setopt($ch, CURLOPT_CAINFO, $cacert); // CA根证书（用来验证的网站证书是否是CA颁布） 
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2); // 检查证书中是否设置域名，并且是否与提供的主机名匹配 
} else if ($SSL && !$CA) { 
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); // 信任任何证书 
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 1); // 检查证书中是否设置域名 
} 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); 
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Expect:')); //避免data数据过长问题 
curl_setopt($ch, CURLOPT_POST, true); 
curl_setopt($ch, CURLOPT_POSTFIELDS, $data); 
//curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($data)); //data with URLEncode 
$ret = curl_exec($ch); 
//var_dump(curl_error($ch)); //查看报错信息 
curl_close($ch); 
return $ret; 
}