Detect when browser receives file download

Question

I have a page that allows the user to download a dynamically-generated file. It takes a long time to generate, so I\'d like to show a \"waiting\" indicator. The problem is,

Answer 1

Primefaces uses cookie polling, too

https://github.com/primefaces/primefaces/blob/32bb00299d00e50b2cba430638468a4145f4edb0/src/main/resources/META-INF/resources/primefaces/core/core.js#L458

    monitorDownload: function(start, complete, monitorKey) {
        if(this.cookiesEnabled()) {
            if(start) {
                start();
            }

            var cookieName = monitorKey ? 'primefaces.download_' + monitorKey : 'primefaces.download';
            window.downloadMonitor = setInterval(function() {
                var downloadComplete = PrimeFaces.getCookie(cookieName);

                if(downloadComplete === 'true') {
                    if(complete) {
                        complete();
                    }
                    clearInterval(window.downloadMonitor);
                    PrimeFaces.setCookie(cookieName, null);
                }
            }, 1000);
        }
    },