We were initially working on Firefox 4.0 and Indexed DB, and I thought of writing some tips and tricks on getting it working. It turns out that Indexed DB is not yet supported on Android browsers and iPhone browser, which is a shame, because we want to run our web-app throughout the whole ecosystem of devices that are now available in the market.
Most browsers support a basic subset of HTML5 standards. But Indexed DB, surprisingly, is not yet heavily adopted. So we were faced with the dilemma of how should we get our app running on Linux, Windows, Mac, iOS, Android etc.
We looked at Web database and Indexed DB, both of which have serious limitations, as of now. So I decided that something had to be done. And I clicked upon a great idea of writing my own API for storage, that works on localstorage.
Now local storage is being supported by all browsers. But it is a very simplistic approach of storing client side data in key-value pairs. This means that you can probably store a To-do list using it, but you may not find it convenient for having something like an electronic data-collection app storing electronic forms, data filled in for the forms, users, settings all in local storage. All this complexity needs a database like storage and organization in form of object stores or tables.
So the local storage API came into being. What it does is - it is just a layer above the localstorage of the browser, so that a developer can write statements to create a table, add columns, add records, retrieve records, search on the records, drop tables, drop full database and more. The API actually stores all data in certain specific key formats so that organization is possible and the API can easily do the operations required by the developer.
The advantages of this approach are manifold, some of which were already mentioned, but here they are again:
1. Requires local storage to be working on the browser, something that's supported on all major browsers right now, including mobile phone browsers.
2. Local storage is synchronous in nature. I am not sure since this could be a disadvantage for some, since they may be looking at asynchronous operations. But the thing is, our app needed synchronous operation, and it much easier to write code with synchronous requests.
3. Is somewhat like Indexed DB in implementation, no sql knowledge is needed.
4. Fairly easy to use the API
For more details and for downloading it, please go to:
https://code.google.com/p/gwt-localstorage-db/
