Implementing Pusher chat in Rails

问题:

Since there is not much up-to-date information with latest versions of Rails and Pusher, how can I implement Pusher in my Rails app to get realtime chat between users? The Pusher documentation shows how to do this with Sinatra, but there isn't anything specific to Rails...

回答1:

Create an initializer file

app/config/initializers/pusher.rb

require 'pusher'

Pusher.url    = 'your-pusher-url'
Pusher.logger = Rails.logger

In your controller, lets assume this is for chat messages:

app/controllers/messages_controller.rb

MessagesController < ApplicationController
  def create
    model = Message.create params_model
    json  = model.to_json
    channel = "private-conversation.#{params[:user_id]}"
    Pusher[channel].trigger 'messages/create', json
  end

  private
    def params_model
      params.require(:message).permit(:id,:body,:user_id)
    end
end

Authorization

app/controllers/pusher_controller.rb

class PusherController < ApplicationController
  protect_from_forgery except: :auth_notify
  skip_before_filter :login_required, only: [:auth_notify]
  def auth
    channel    = params[:channel_name]
    socket_id  = params[:socket_id]

    valid = false
    valid = true if channel =~ /private-conversation\.(\d+)/

    if valid
      response = Pusher[channel].authenticate socket_id
      render json: response
    else
      render text: 'Not authorized', status: '403'
    end
  end
end

Routes:

routes.rb

YourApp::Application.routes.draw do
  resources :messages
  post '/pusher/auth'    => 'pusher#auth'
end

Somewhere in your coffescript, most likely in application.coffee, this assumes you have the pusher cdn js file in your application.html.haml and jquery installed.

$->
    user_id = $('meta[name=user-id]').attr('user_id')
    key     = $('meta[name=pusher-key]').attr('content')
    csrf    = $('meta[name=csrf-token]').attr('content')
    @pusher = new Pusher key,
      auth:
        headers:
          'X-CSRF-Token': csrf
        params:
          user_id: user_id

notice that you should added meta tags to your head so you easily grab csrf token, user_id and pusher key. You of course need csrf token to stop spoofing.

In your application.html.haml

!!! XML
!!! 5
%html
  %head
    = csrf_meta_tag
    = tag :meta, name: 'pusher-key', content: "#{current_user.id}"
    = tag :meta, name: 'pusher-key', content: 'pusher_public_key'
  %body
    = javascript_include_tag '//js.pusher.com/2.2/pusher.min.js'
    = javascript_include_tag :application

current_user assumes you are using some kind of authenication. csrf_meta_tag is a built in rails helper. Notice that I put my js on the last line of body. do not place your js in the head.