使用ajax的post方式下载excel

项目需求，前端发起ajax请求，后端生成excel并下载，同时需要在header头中，带上token验证信息，参考了很多文章，最终实现如下：

PHP后端使用base64:

$filename = 'demo.xlsx';
$objWriter = PHPExcel_IOFactory::createWriter($objectPHPExcel, 'Excel2007');
ob_start();
$objWriter->save("php://output");
$xlsData = ob_get_contents();
ob_end_clean();
return Api::success(['filename' => $filename, 'file' => "data:application/vnd.ms-excel;base64," . base64_encode($xlsData)]);

JS前端：

$('.download').click(function(){

        var url = "http://xxxx.com/group/bi/export";
        var params = {
            from_date: '2017-09-01',
            to_date: '2017-09-08',
            group_id: 1
        };
        $.ajax({
            type:'POST',
            url: url,
            data: params,
            beforeSend: function(request) {
                request.setRequestHeader("Authorization", "token信息，验证身份");
            },
            success: function(redata) {

                // 创建a标签，设置属性，并触发点击下载
                var $a = $("<a>");
                $a.attr("href", redata.data.file);
                $a.attr("download", redata.data.filename);
                $("body").append($a);
                $a[0].click();
                $a.remove();
            }
        });
    });