javascript - 尝试检测下载何时准备就绪

Question

我正在尝试动态创建一个 zip 文件夹。zip 将保存用户从托管在 Amazon S3 上的库中选择的图像。以下是我到目前为止的代码。

从 POST 请求 URL

function download_multi() {

    //$user_id, $files, $project_id, $project_name
    $this->load->library('aws');

    $user = User::get_user();
    $requestedHashes = $this->input->post("files");
    $files = array();

    foreach($requestedHashes as $hash) {
        $files[] = hex_to_string($hash);
    }

    $project_id = $this->input->post("projectid");

    $project = new Project($project_id);

    $project_name = $project->project_name;



    $this->aws->create_zip($user->id, $files, $project_id, $project_name, (int)$this->input->post("downloadToken"));


}

创建邮编

public function create_zip($user_id, $files, $project_id, $project_name, $cookie) {

        //create a random folder name to avoid collision.
        $this->folder = md5(time() . rand());

        if(!mkdir('./files' . '/' . $this->folder, 0777, TRUE)) {
            exit("Folder not created\n");
        }

        //create zipfile

        $this->filename = $this->local_file_path . $this->folder . '/files.zip';

        $zip = new ZipArchive();

        if ($zip->open($this->filename, ZIPARCHIVE::CREATE) !== TRUE) {
            exit("cannot open <$this->filename>\n");
        }

        //create options for downloading each file to the server
        //temporarily to add to archive
        $opt = array('preauth' => '+1 minutes');
        //download each file to the server.
        foreach ($files as $file) {

            //generate a link.
            $response = $this->s3->get_object($this->bucket, $this->_make_path($user_id, $project_id) . $file, $opt);
            //get filename.
            $file_name = explode('?', basename($response));
            //add filename to array
            $local_files[] = $file_name[0];
            //copy the file from aws to local server. 
            if(copy($response, $this->local_file_path . $this->folder . '/' . $file_name[0])) {
                $zip->addFile($this->local_file_path . $this->folder . '/' . $file_name[0], $file_name[0]);
            }
        }
        //close zip
        $zip->close();

        //die(var_dump(file_exists($this->filename)));
        //kill each temp file
        /*foreach ($local_files as $file) {
            unlink($this->local_file_path . $this->folder . '/' . $file);
        }*/
        //load download helper.


        $this->ci->load->helper('download');

        //download
        stream_download("APP_{$project_name}_" . time() . ".zip", $this->filename, $cookie);
    }

下载助手

function stream_download($filename = '', $data = '', $cookie = NULL)
{
    //die($cookie);
    if ($filename == '' OR $data == '')
    {
        return FALSE;
    }

    // Try to determine if the filename includes a file extension.
    // We need it in order to set the MIME type
    if (FALSE === strpos($filename, '.'))
    {
        return FALSE;
    }

    // Grab the file extension
    $x = explode('.', $filename);
    $extension = end($x);

    // Load the mime types
    if (defined('ENVIRONMENT') AND is_file(APPPATH.'config/'.ENVIRONMENT.'/mimes.php'))
    {
        include(APPPATH.'config/'.ENVIRONMENT.'/mimes.php');
    }
    elseif (is_file(APPPATH.'config/mimes.php'))
    {
        include(APPPATH.'config/mimes.php');
    }

    // Set a default mime if we can't find it
    if ( ! isset($mimes[$extension]))
    {
        $mime = 'application/octet-stream';
    }
    else
    {
        $mime = (is_array($mimes[$extension])) ? $mimes[$extension][0] : $mimes[$extension];
    }

    // Generate the server headers
    if (strpos($_SERVER['HTTP_USER_AGENT'], "MSIE") !== FALSE)
    {
        header('Content-Type: "'.$mime.'"');
        header('Set-Cookie: fileDownloadToken="'.$cookie.'"');
        header('Content-Disposition: attachment; filename="'.$filename.'"');
        header('Expires: 0');
        header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
        header("Content-Transfer-Encoding: binary");
        header('Pragma: public');
        header("Content-Length: ".filesize($data));
    }
    else
    {
        header('Content-Type: "'.$mime.'"');
        header('Set-Cookie: fileDownloadToken="'.$cookie.'"');
        header('Content-Disposition: attachment; filename="'.$filename.'"');
        header("Content-Transfer-Encoding: binary");
        header('Expires: 0');
        header('Pragma: no-cache');
        header("Content-Length: ".filesize($data));
    }
    flush();
}

JAVASCRIPT

downloadSelectedFiles: function(e) {

        //window.XmlHttpRequest = new XmlHttpRequest();

        console.log("Block UI");

        var that = this;

        var url = config.base + "projects/download_multi";

        var projectId = $("li.selected").find('li.js-select-file').data('projectid');
        var images = {};
            images.hashes = [];

        var token = new Date().getTime();

        $("li.selected").each(function(i){

            images.hashes.push($(this).find('li.js-select-file').data('filename'));

        });

        //window.location.href = url;
        $.post(url, { files: images.hashes, projectid: projectId, downloadToken: token }, function(data){



            var fileDownloadCheckTimer = window.setInterval(function() {
                console.log("checking...");
                var cookieValue = $.cookie('fileDownloadToken');
                console.log(parseInt(cookieValue), parseInt(token));
                if( parseInt(cookieValue) == parseInt(token) ) {
                    that.finishDownload()
                } else {
                    console.log("Don't Match");
                }

            }, 1000);

            /*var iframe = document.createElement("iframe"); 
            iframe.src = config.base + data; 
            iframe.style.display = "none"; 
            document.body.appendChild(iframe);
            return false;*/

        });

    },

    finishDownload: function() {

        window.clearInterval(fileDownloadCheckTimer);
        $.removeCookie('fileDownloadToken');
        console.log("Unblock UI");


    }

我注意到的一件事是，当我检查 cookie 值和令牌匹配时，一个是字符串，另一个是 int。除此之外，我也不是我只在我的 reposonse 中获得标题，我从未真正获得下载窗口。