@startupjs/sharedb-access

Install

yarn add @startupjs/sharedb-access

Usage

const shareDbAccess = require('sharedb-access')
new shareDbAccess(backend, options)

Parameters

options (Object):

backend: your ShareDB backend instance
options (optional):
- dontUseOldDocs: if true then don't save unupdated docs for update action. Default: false.
- opCreatorUserIdPath: path to userId for op's meta

Using sharedb-access you can control create, read, update, and delete database operation for every collection. You can use two types of rules: allow and deny. By default all operations are denied. So, you should add some rules to allow them. If at least one allow rule allows the write, and no deny rules deny the write, then the write is allowed to proceed.

You can call allow and deny rules as many times as you like. The functions should return true if they think the operation should be allowed for allow rules and denied for deny rules. Otherwise they should return false, or nothing at all (undefined).

Create

// Allow create-operation for collection 'items'

// docId - id of your doc for access-control
// doc   - document object
// session - your connect session

backend.allowCreate('items', async (docId, doc, session) => {
  return true
})

// Deny creation if user is not admin
backend.denyCreate('items', async (docId, doc, session) => {
  return !session.isAdmin
})

// So, finally, only admins can create docs in 'items' collection
// the same results is if you just write:

backend.allowCreate('items', async (docId, doc, session) => {
  return session.isAdmin
})

Read

Interface is like create-operation

backend.allowRead('items', async (docId, doc, session) => {
  // Allow all operations
  return true
})

backend.denyRead('items', async (docId, doc, session) => {
  // But only if the reader is owner of the doc
  return doc.ownerId !== session.userId
})

Delete

Interface is like create-operation

backend.allowDelete('items', async (docId, doc, session) => {
  // Only owners can delete docs
  return doc.ownerId === session.userId
})

backend.denyDelete('items', async (docId, doc, session) => {
  // But deny deletion if it's a special type of docs
  return doc.type === 'liveForever'
})

Update

// docId - id of your doc for access-control
// oldDoc  - document object (before update)
// session - your connect session
// ops    - array of OT operations
// newDoc  - document object (after update)

const allowUpdateAll = async (docId, oldDoc, session, ops, newDoc) => {
  return true
}

backend.allowUpdate('items', allowUpdateAll);

@startupjs/sharedb-access