[ActionCable] Filter data based on params

[Stefan Buhrmester]

Hello all,

I've been searching a lot but wasn't able to find a solution for this (what I thought should be a really "simple" thing).

Basically, what I want to do is to create a subscription where the messages that are received by the subscriber are filtered based on the passed params.

For example, something like this:

class PeopleChannel < ApplicationCable::Channel

 # only send people that are older than params[:min_age]
  def subscribed

   stream_for Person do |person|
      person.age > params[:min_age]

   end

 end

end

Or, what would be a kick-ass feature but probably difficult to implement, would be to stream from an active record relation, and send only the records that are included in the relation (even if they have just been created).

class PeopleChannel < ApplicationCable::Channel

 # only send things that are older than some age
  def subscribed
    people = Person.where('age > ?', params[:min_age])

   stream_for people

 end

end

Anybody got any ideas how to do this? Filtering messages seems like such a basic thing but I can't find a way.

Stefan

[Stefan Buhrmester]

Ok, just dug into the source code and think I found a solution:

stream_from 'some_channel', coder: ActiveSupport::JSON do |person|
  transmit(thing) if (person['age'].to_i > params[:min_age])
end