Altering Firefox "Address not found" page behavior

Question

I have a (mostly) unmanaged computer stuck someplace not easily reachable that has only one purpose: to display a specific web page on a large screen connected to the said computer's video card. This is achieved by running Firefox on bare X11 in full-screen mode.

Now, the page itself has a script that reloads it every X minutes; however, in case of a network/web server outage, which happen quite frequently and cannot be currently avoided, the browser refreshes the page and gets stuck on the "Address not found" page. As soon as it gets there, there's only one way to get things back: to reload the web page manually.

The question: is it possible to modify Firefox's settings in such a way that it automatically attempts to reload the target page every X minutes while being stuck at the "Address not found" error page? Thank you.

Answer 1

One approach you can take is to point Firefox at a frameset instead of directly at your page, then add some javascript in the parent which reloads the frame. Since the parent page doesn't reload it doesn't get stuck when connectivity is lost and continues to attempt to reload the target page.

Another possibility would be to write an addon to Firefox. The ErrorZilla extension replaces the standard error page, it's under the MPL so you could have a look at the code and change the page to do what you want.

Answer 2

When you say "running Firefox on bare X11 in full-screen mode" I immediately assume you are running a *nix locally on this system.

Under this assumption there is an other option: Install Apache locally and simply configure it to proxy the webserver at 'localhost' to the single page you need.

When the network is out or there is an other kind of error you can simply change the local 404, 500, etc. error pages of this Apache.

These 'error pages' can all have a different retry period. Depending on the type of error.

Very simple and no additional programming/plugins needed. All OOTB software.

Answer 3

As well as the frameset option suggested by robertc, you could also make the page refresh most or parts of itself via a HTTP request made by client-side javascript.

This would mean that the page would never be left with an error displaying (or blank, while the browser waits for a timeout to occur if the page is inaccessible) and if the machine is slow this can reduced on-screen flicker during page updates (you can record the last result and not update anything if the information hasn't changed), though it would be a little more work to implement than the simpler frameset option.

Of course if you want an error page to be displayed (instead of the "last known good" information which may at that point be out-of-date) you can display your own message styled to match the theme of the usual display, or perhaps just add a warning to the usual display to the effect that the information shown has not been updated for a while.

Answer 4

The extension TabMixPlus adds automatic page refresh timers to the rclick menu. Just rclick on a blank part of the webpage and choose a setting under 'reload every'. I'm not actually sure what it does if it encounters an error, but it's a simple solution if it works.