localStorage and locking

Question

Since (html5) localStorage and its equivalencies persist in between tabs and windows, I've thought about using it for message passing. The problem is that fetch and store are different operations, and therefore not atomic. I have models that rely on UUID generation, conflict resolutions, and beaconing to do the small subset of what I need to do, but my real question is this:

Since the local storage is a shared memory resource, what are the locking mechanisms available for mutual access?

Answer 1

I think what you really need is Channel Messaging, though as far as I'm aware no-one has implemented it yet. It allows arbitrary client side messaging between scripts.

Answer 2

There aren't any built-in. You'll have to come up with your own locking mechanism. You can off course use any of the existing methods that other people have come up with for other things (like locking in memcache for instance).

Answer 3

Benjamin Dumke-von der Ehe recently came up with some (experimental) locking code for localStorage: http://balpha.de/2012/03/javascript-concurrency-and-locking-the-html5-localstorage/