ROM-Firebase Adapter

This project builds on the excellent rom-http and firebase libraries to provide an interface for communicating with a Firebase Realtime Database.

How this works

To start using this, create a ROM::Configuration like so:

require 'rom/firebase'

configuration = ROM::Configuration.new(
  :firebase,
  uri: 'https://your-firebase-db-name.firebaseio.com',
  headers: { Accept: 'application/json' },
  request_handler: ROM::Firebase::RequestHandler.new(
    File.expand_path('../config/your-firebase-db-name.json', __dir__)
  ), # or your own class
  response_handler: ROM::Firebase::ResponseHandler # or your own class
)

Notes:

You'll need to change the path to your Firebase JSON file to match where it is stored for you.
You can use your own RequestHandler or ResponseHandler class if you want customised interactions.

This configuration can be passed to a repository class which mirrors a schema inside your Firebase Realtime Database's key value store, e.g. let's say we are storing Pages, here is a working example. Note the use of key as the primary key.

class PageRepository < ROM::Firebase::Repository[:pages]
end

class Pages < ROM::Relation[:firebase]
  schema do
    attribute :createdAt, ::ROM::Firebase::Types::Timestamp
    attribute :title, Types::Strict::String
    attribute :description, Types::Strict::String
    attribute :key, Types::Strict::String.meta(primary_key: true)
  end
end

configuration.register_relation(Pages)
container = ROM.container(configuration)
repo = PageRepository.new(container)

Now you can query it:

page = repo.create(
  createdAt: ::Firebase::ServerValue::TIMESTAMP,
  title: 'Hello World',
  description: 'A wild page appears'
)

This should return a ROM::Struct::Page with the created attributes:

=> #<ROM::Struct::Page createdAt=1552999123000 title="Hello World" description="A wild page appears" key="-LaKxW4D8LTpwIWN3N9J">

And, in your Firebase Database console, you'll see a new pages node with one record.

To query this, you can use some of the built in functionality:

repo.where { |page| page.title == 'Hello World' }
=> [#<ROM::Struct::Page createdAt="1552999123000" title="Hello World" description="A wild page appears" key="-LaKxW4D8LTpwIWN3N9J">]

To update it, use a ROM changeset:

repo.by_pk(page.key).changeset(:update, description: 'A wild page is updated').commit
=> [#<ROM::Struct::Page createdAt="1552999123000" title="Hello World" description="A wild page is updated" key="-LaKxW4D8LTpwIWN3N9J">]

To delete our page is simple:

repo.by_pk(page.key).delete
=> nil

You can't currently delete multiple records at once through relations, but there is a workaround on the repository level:

keys = ["-LaKxW4D8LTpwIWN3N9J", "-LaKxW4D8LTpwIWN3N9K"]
repo.delete(keys)

So, for example, if you wanted to delete the last 2 entries you could:

repo.delete(repo.limit(2).to_a.map(&:key))

rom-firebase

Runtime

ROM-Firebase Adapter

How this works