Class: LiveRecord::ChangesChannel

Inherits:
BaseChannel
  • Object
show all
Defined in:
app/channels/live_record/changes_channel.rb

Overview

This channel streams changes (update/destroy) from records to connected clients, through ActiveRecord callbacks This also supports syncing (old changes) when a client somehow got disconnected (i.e. network problems), through a separate cache ‘live_record_updates` table.

Instance Method Summary collapse

Instance Method Details

#subscribed ⇒ Object 



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# File 'app/channels/live_record/changes_channel.rb', line 6

def subscribed
  find_record_from_params(params) do |record|
    authorised_attributes = authorised_attributes(record, current_user)

    if authorised_attributes.present?
      stream_for record, coder: ActiveSupport::JSON do |message|
        begin
          record.reload
        rescue ActiveRecord::RecordNotFound
        end
        
        authorised_attributes = authorised_attributes(record, current_user)

        # if not just :id
        if authorised_attributes.size > 1
          response = filtered_message(message, authorised_attributes)
          transmit response if response.present?
        else
          respond_with_error(:forbidden)
          reject_subscription
        end
      end
    else
      respond_with_error(:forbidden)
      reject
    end
  end
end

#sync_record(data) ⇒ Object 



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# File 'app/channels/live_record/changes_channel.rb', line 35

def sync_record(data)
  find_record_from_params(data.symbolize_keys) do |record|
    authorised_attributes = authorised_attributes(record, current_user)

    # if not just :id
    if authorised_attributes.size > 1
      live_record_update = LiveRecordUpdate.where(
        recordable_type: record.class.name,
        recordable_id: record.id
      ).where(
        'created_at >= ?', DateTime.parse(data['stale_since']) - LiveRecord.configuration.sync_record_buffer_time
      ).order(id: :asc)
      
      if live_record_update.exists?
        message = { 'action' => 'update', 'attributes' => record.attributes }
        response = filtered_message(message, authorised_attributes)
        transmit response if response.present?
      end
    else
      respond_with_error(:forbidden)
      reject_subscription
    end
  end
end