最近对接百度营销的信息流接口，上传视频那块，我们使用的是自己的视频库，对应表里存的都是地址，所以需要转存到百度，后端需要用curl请求接口，故此拼接

//推送文件流
    public static function putPart($url, $param){
        $delimiter = uniqid();
        $imageInfo = pathinfo($param['file']);
        //编译请求头格式和数据流
        $data = '';
        $eol = PHP_EOL;
        $upload = file_get_contents($param['file']);
        $param['filename'] = $imageInfo['basename'];
        unset($param['file']);
        foreach ($param as $name => $content) {
            $data .= "--" . $delimiter . PHP_EOL . 'Content-Disposition: form-data; name="' . $name . PHP_EOL . PHP_EOL . $content . PHP_EOL;
        }
        $data .= "--" . $delimiter . $eol . 'Content-Disposition: form-data; name="file"; filename="' . $param['filename'] . '"' . PHP_EOL . 'Content-Type:application/octet-stream'. PHP_EOL . PHP_EOL;
        $data .= $upload . PHP_EOL;
        $data .= "--" . $delimiter . "--" . PHP_EOL;
        $post_data = $data;
        $curl = curl_init($url);
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($curl, CURLOPT_POST, true);
        curl_setopt($curl, CURLOPT_POSTFIELDS, $post_data);
        curl_setopt($curl, CURLOPT_HTTPHEADER, ["Content-Type: multipart/form-data; boundary=" . $delimiter, "Content-Length: " . strlen($post_data)]);
        $response = curl_exec($curl);
        curl_close($curl);
        return json_decode($response, true);
    }

注：拼接时此处分隔符，会有影响，网上版本使用'\r\n'，这个不妥，不同环境的换行符不同，linux使用的是\n，所以使用常量最妥当