Rest / HTML - If server stops detect if server starts again?

Question

Something I am playing with at the moment is a Rest / HTML page that dynamically updates via JSON calls.

Now in the case that I want this to run on as low a bandwidth as possible.

So if the server is shut down, then booted up again I want the updates to continue again in most cases this works some cases parts of the javascript won't work and it times out.

So what is a low overhead solution to detect that the Server has started up again?

(Looking for good ideas or other methods to do this)

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thoughts:
So far I have thought of having a status request but this uses bandwidth again to continually run?

Or how to only run this status request once the server had gone down and stop when its up?

Answer 1

You could use the setInterval function to continuously poll the server for updates. Once a request fails you could enter a so called safe-mode by sending only HEAD requests (and as suggested by @sje397 also increase the timeout interval) to reduce bandwidth and once it succeeds you enter again normal mode and continue with GET/POST.

There are also more exotic things like COMET and Web Sockets in HTML 5 that allow the server to push updates to the client.