php5.6关于curl以＠方式上传文件的变化及解决七牛上传时报file is not specified in multipart的问题

        $ch = curl_init ();
        $fields = $params;
        $fields ["file"] = "@" . $file;
        curl_setopt ( $ch, CURLOPT_URL, $url );
        curl_setopt ( $ch, CURLOPT_POST, 1 );
        curl_setopt ( $ch, CURLOPT_POSTFIELDS, $fields );
        curl_setopt ( $ch, CURLOPT_RETURNTRANSFER, 1 );
        $response = curl_exec ( $ch );

在php5.6之前的版本上以上面的代码上传文件是没有问题的，但从php5.6.0开始，需要加上curl_setopt ( $ch, CURLOPT_SAFE_UPLOAD, false);这行代码方可上传，否则取不到文件。

最终的代码：

        $ch = curl_init ();
        curl_setopt ( $ch, CURLOPT_SAFE_UPLOAD, false);
        $fields = $params;
        $fields ["file"] = "@" . $file;
        curl_setopt ( $ch, CURLOPT_URL, $url );
        curl_setopt ( $ch, CURLOPT_POST, 1 );
        curl_setopt ( $ch, CURLOPT_POSTFIELDS, $fields );
        curl_setopt ( $ch, CURLOPT_RETURNTRANSFER, 1 );
        $response = curl_exec ( $ch );

注意：curl_setopt ( $ch, CURLOPT_SAFE_UPLOAD, false);这行代码必须放在下面这行代码之前<pre name="code" class="plain">curl_setopt ( $ch, CURLOPT_POSTFIELDS, $fields );否则上传到七牛时会报file is not specified in multipart的错误。

php官网上也有此介绍http://cn2.php.net/manual/en/function.curl-setopt.php