ExtJS download utility

util.js

// This utility method allows downloading files with a failure and a success callback.
// It uses the following setting in the fields property:
//
// Key     | Default                   | Description
// ------- | ------------------------- | -----------
// url     | MODx.config.connector_url | The connector url
// timeout | 30                        | Set a polling timeout
// debug   | false                     | Log the polling in the console
// params  | {}                        | Additional params for the connector url
// success | null                      | Callback called after a successful download,
// failure | null                      | Callback called after a failed download

// To use the success callback, the download processor has to set a cookie i.e. by:
// if ($this->getProperty('cookieName')) {
//     setcookie($this->getProperty('cookieName'), 'true', time() + 10, '/');
// }

Packagename.util.FileDownload = function (fields) {
    if (!Ext.isObject(fields)) {
        return;
    }

    let me = this;
    me.clearCookie = function () {
        Ext.util.Cookies.set(cookieName, null, new Date("January 1, 1970"), '/');
        Ext.util.Cookies.clear(cookieName, '/');
    }
    me.randomHex = function (len) {
        const hex = '0123456789ABCDEF';
        let output = '';
        for (let i = 0; i < len; ++i) {
            output += hex.charAt(Math.floor(Math.random() * hex.length));
        }
        return output;
    }
    me.isFinished = function (successCallback, failureCallback) {
        // Check if file is started downloading
        if (Ext.util.Cookies.get(cookieName) && Ext.util.Cookies.get(cookieName) === 'true') {
            me.clearCookie();
            if (typeof successCallback === 'function') {
                successCallback({success: true, message: _('packagename.file_msg_download_success')});
            }
            return;
        }
        // Check for error / IF any error happens the frame will have content
        try {
            var response = frame.dom.contentDocument.body.innerHTML;
            if (response.length > 0) {
                let result = Ext.decode(frame.dom.contentDocument.body.innerHTML);
                result = (result) ? result : {success: false, message: _('packagename.file_msg_download_error')};
                me.failure(failureCallback, result);
                frame.dom.contentDocument.body.innerHTML = "";
                return;
            }
        } catch (e) {
            me.failure(failureCallback, {success: false, message: MODx.util.safeHtml(response)});
            return;
        }

        if (polling) {
            if (debug) {
                console.log('polling ' + polling);
            }
            // Download is not finished. Check again in 100 milliseconds.
            window.setTimeout(function () {
                polling--;
                me.isFinished(successCallback, failureCallback);
            }, 100);
        } else {
            // Polling timeout with no fileDownload cookie set
            me.failure(failureCallback, {success: false, message: _('packagename.file_msg_download_timeout')});
        }
    };
    me.failure = function (failureCallback, result) {
        me.clearCookie();
        if (failureCallback) {
            failureCallback(result);
        }
    }

    const cookieName = 'fileDownload' + me.randomHex(16),
        ident = fields.ident || 'filedownload-' + Ext.id(),
        url = fields.url || MODx.config.connector_url,
        debug = fields.debug || false;

    let params = fields.params || {},
        polling = fields.timeout * 10 || 300,
        successCallback = fields.success || null,
        failureCallback = fields.failure || null,
        body = Ext.getBody();

    let frame = body.createChild({
            tag: 'iframe',
            cls: 'x-hidden',
            id: ident + '-iframe',
            name: ident + '-iframe',
        }),
        form = body.createChild({
            tag: 'form',
            cls: 'x-hidden',
            id: ident + '-form',
            action: url,
            target: ident + '-iframe',
            method: 'post',
        });
    params.HTTP_MODAUTH = MODx.siteId;
    if (typeof successCallback === 'function') {
        params.cookieName = cookieName;
    } else {
        polling = 0;
    }
    Ext.iterate(params, function (name, value) {
        let textarea = form.createChild({
            tag: 'textarea',
            cls: 'x-hidden',
            id: ident + '-' + name,
            name: name
        });
        textarea.dom.innerText = value;
    });
    form.dom.submit();
    if (successCallback || failureCallback) {
        me.isFinished(successCallback, failureCallback);
    }
};