php curl常见错误：SSL错误、bool(false)

　　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, CURLOPT_HTTPHEADER, array( 'Expect:' ) );

　　…which basically overrides the original ‘Expect:' header with an empty one.

　　Hope this helps someone.