retful上传文件php的实现

项目中要使用restful上传文件到服务器，一直不能成功，后生成相关串后在postman中上传成功，利用这个工具生成php curl的代码，后逐步比对产生以下代码。   

/**
     * 上传文件
     * @param unknown $filename
     */
    function fileUpload($filename,$type)
    {
        $serviceName='imageup';
        $contents = file_get_contents($filename);
        //content boundary
        $boundary   = md5(time());
        $postStr  = "";
        $postStr .="-----".$boundary." ";
        $postStr .="Content-Disposition: form-data; name="file"; filename="".$filename."" ";
        $postStr .="Content-Type: jpg ";     
        $postStr .=$contents." ";
        $postStr .="-----".$boundary."--";
       
        $timestamp=$this->getMillisecond();
        $signstr=$this->sign('', $timestamp, $this->prikey);
        $post_data=array("v"=>$this->ver,
            "ts"=>$timestamp,
            "sign"=>$signstr,
            "user"=>$this->userSn
        );
        $o = "";
        foreach ( $post_data as $k => $v )
        {
            $o.= "$k=" . urlencode( $v ). "&" ;
        }
        $post_data = substr($o,0,-1);
        $timeout = 30;      
        $postUrl = $this->url_province.$serviceName."/".$type."/" .'?' . $post_data;
       
        $ch = curl_init();
        $boundary = md5(time());
        curl_setopt_array($ch, array(
            CURLOPT_URL => $postUrl,
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_MAXREDIRS => 10,
            CURLOPT_TIMEOUT => 300,
            CURLOPT_CUSTOMREQUEST => "POST",
            CURLOPT_POSTFIELDS => $postStr,
            CURLOPT_HTTPHEADER => array(
                "cache-control: no-cache",
                "content-type: multipart/form-data; boundary=---".$boundary,
            ),
        ));
        $result = curl_exec($ch);
        curl_close($ch);
 
        return $result;              
    }

$boundary 的格式不能改变，“-----”、“ "上面程序已经过测试