dat-polyfill

Add support for the DatArchive API to the web

How to

• Clone the repo git clone git@github.com:RangerMauve/dat-polyfill.git
• npm install the dependencies
• Compile polyfill.js using your favorite build tools
• Embed the bundled JS into your HTML
  • Make sure it gets loaded before any application code
• Set up a dat-gateway on localhost:3000. You'll need to clone the repo since it's not on NPM
• Optionally set a global variable called DEFAULT_DAT_GATEWAY to point to the gateway you want. (Set it up before the polyfill loads)
• Profit!

Limitations

• Since data is stored in IndexedDB, there's a limit on how much you can store
• Synchronizing with a public gateway isn't as secure as using a local one since it can inspect the dat URLs you are trying to load.
• Local gateways can be a lot slower

How it works

It uses a dat-gateway in order to replicate Dats with the rest of the Dat ecosystem over websockets

It uses the following logic to detect a Dat gateway to use:

• If the URL has the parameter DAT_GATEWAY in the query string, parse it out and use it
• If the global variable DEFAULT_DAT_GATEWAY exists, use that
• If the page is being served through dat-gateway (by detecting the subdomain redirection logic), use that
• If localStorage.DAT_GATEWAY is defined, use that
• Use http://localhost:3000

When a new DatArchive is created through either DatArchive.create() or DatArchive.fork(), it gets stored in IndexedDB inside the dat://storage DB. All these dats share the same IndexedDB instance, but they are separated from each other. The list of created archives is stored in localStorage.getItem('dat://storage').

When you use new DatArchive(url), if it was created locally, it will load it from IndexedDB, else it will store it in memory.

It supports an iframe mode, where if it's served from within an iframe, it will delegate storage to the parent frame. Check out demo/server/index.js for how to set that up. The benefit is that storage is de-duplicated between origins.