WinstonFassett / y-levelup

LevelDB database adapter for Yjs

levelup database adapter for Yjs

Use the levelup database adapter to store your shared data persistently in NodeJs applications. The changes will persist after restart.

Works with any levelup backend.

For more info see:

• https://github.com/Level/levelup/wiki/Modules#storage
• https://github.com/Level/awesome

How it works

This is a fork of y-leveldb, which uses leveldown to store data in the filesystem.

In order to support remote databases via levelup, a couple of changes have been made:

• Rather than creating a DB per room, use a single database for all rooms and implement rooms as sublevels.
• For optimal room startup, run the OS as an in-memory database whose operations are also streamed to the remote database.

Caveats

• This was an experiment that has turned out to work pretty well.
• so YMMV.
• This is just source code adapted from its original app.
• I haven't worked out the YJS build system yet so there is no dist or NPM package.
• SS and DS are not run in-memory as OS is. It might be worth exploring.

Example

1. Create/connect to levelup root database

var db = require('levelup')(process.env.MONGODB_URI || 'localhost/yjs-rooms', { db: require('mongodown') })

2. Initialize y-levelup with database

require('y-levelup')(Y, db)

3. Create Y instance

Y({
  db: {
    name: 'levelup',
    namespace: 'textarea-example' (optional - defaults to connector.room),
  },
  connector: {
    name: 'websockets-client', // use the websockets connector
    room: 'textarea-example'
  },
  share: {
    textarea: 'Text' // y.share.textarea is of type Y.Text
  }
}).then(function (y) {
  // bind the textarea to a shared text element
  y.share.textarea.bind(document.getElementById('textfield'))
}

License

Yjs is licensed under the MIT License.

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