CODEWITHSUNDEEP
javascript
Brecky Morris
Brecky Morris

Reputation: 221

periodic reloading of webpage, but only if the page is available

I've been looking for a solution that will reload the a page at a specified interval, but only if the server from which that page comes from can deliver the page. Network problems, server problems, etc. should prevent the page from trying to reload. I'm a little surprised that there isn't more of a ready solution, since it seems like this would be the preferred behavior most of the time, instead of loading a blank page with an error message.

I tried to add on to a solution already on stackoverflow:

Javascript: Check if server is online?

but I while it does reload periodically, it doesn't stop trying to reload if the network isn't working (I turn WiFi off to simulate this). I did not try to simulate a server problem.

Here is my non-working version of a periodic reload:

function reloadpage() {
   setTimeout(checkServerStatus, 60000);
}

function checkServerStatus() {
   var img = document.body.appendChild(document.createElement("img"));
   img.onload = function() {
      location.reload(true);
   };
   img.src = "http://some/image.jpg";
}

Upvotes: 2

Views: 188

Answers (2)

matcheek
matcheek

Reputation: 5147

function reloadpage() {
    $.ajax({
        url: "your url",
        type: "GET",
        complete: function(e, xhr, settings) {
            if (e.status === 200 || e.status == 304) {
                location.reload();
            } else {
                alert("server unreacheable. Do not reload");
            }
        }
    });
    setTimeout(reloadpage, 10000);
}

setTimeout(reloadpage, 10000);

Upvotes: 1

Wainage
Wainage

Reputation: 5412

Try this

function checkPage(interval) {
    interval = interval || 10*60*1000;  // every 10 minutes
    setTimeout(function(){
        $.ajax({ method: 'HEAD', url: 'http://'})
            .done(function(){           // headers retrieved ... it's alive
                location.reload();
            })
            .fail(function(){           // sorry we failed
                checkPage(6000);        // check again but in 1 min
            })
    }, interval);
}

checkPage(5*60*1000);                   // reload in 5 minutes

This will request server headers after interval milliseconds. If they arrive, server is up and we reload. If not we check again in 1 minute.

If you want to guarantee the page is there, change HEAD to GET and check the html returned is what you expect it to be.

Upvotes: 2

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