症状：PHP curl调用https出错
排查方法：在命令行中使用curl调用试试。
原因：服务器所在机房无法验证SSL证书。
解决办法：跳过SSL证书检查。
curl_setopt($ch,CURLOPT_SSL_VERIFYPEER,false); 症状：PHP curl调用curl_exec返回bool(false)，命令行curl调用正常。

排查方法：

var_dump(curl_error($ch));
返回：
string(23) "Empty reply from server"

再排查：

curl_setopt($ch,CURLOPT_HEADER,true);
curl_setopt($ch,CURLOPT_RETURNTRANSFER,false);

返回：

HTTP/1.1 100 Continue
Connection: close
原因：PHP curl接收到HTTP 100就结束了，应该继续接收HTTP 200

解决方案：

curl_setopt($ch,CURLOPT_HTTPHEADER,array('Expect:'));

PHP and cURL: Disabling 100-continue header

Published June 15th,2006
I've been using cURL (through PHP) to build a sort of proxy for a project I'm working on. I need to parse the returned headers (to recover the HTTP status),so had included a very simple script to do so. It had worked fine in the past,but for some reason barfed in this case. A closer look at what was being returned revealed that for some reason,Apache was prepending the ‘normal' headers with an extra response header: HTTP/1.1 100 Continue HTTP/1.1 200 OK Date: Fri,09 Jun 2006 15:23:42 GMT
Server: Apache
...A bit of Googling revealed that this was to do with a header that cURL sends by default: Expect: 100-continue …which in turns tells Apache to send the extra header. I poked around a fair bit but couldn't quite find a workable solution short of manually removing the header in PHP,which seemed a bit clumsy. Finally,on a hunch I tried this: curl_setopt( $curl_handle,array( 'Expect:' ) ); …which basically overrides the original ‘Expect:' header with an empty one. Hope this helps someone.