prototyping server sent events

app/controllers/api/v1/activity_log_controller.rb

@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+class Api::V1::ActivityLogController < Api::BaseController
+  include ActionController::Live
+
+  # before_action -> { doorkeeper_authorize! :read, :'read:lists' }, only: [:index, :show]
+  # before_action -> { doorkeeper_authorize! :write, :'write:lists' }, except: [:index, :show]
+
+  # before_action :require_user!
+  # before_action :set_list, except: [:index, :create]
+  #
+  #
+  #
+  class Foo
+    attr_accessor :test
+  end
+
+  rescue_from ArgumentError do |e|
+    render json: { error: e.to_s }, status: 422
+  end
+
+  def index
+    render :text => "hello world"
+  end
+
+  def show
+    response.headers['Content-Type'] = 'text/event-stream'
+    # hack to avoid computing Etag, which delays sending of data
+    response.headers['Last-Modified'] = Time.now.httpdate
+
+    sse = SSE.new(response.stream)
+
+    begin
+      100.times {
+        f = Foo.new
+        f.test = "xxx"
+        sse.write f.to_json
+        sleep 1
+      }
+    ensure
+      sse.close
+    end
+  end
+end

app/javascript/mastodon/features/activity_log/index.js

@@ -30,8 +30,25 @@ class Lists extends ImmutablePureComponent {
     multiColumn: PropTypes.bool,
   };
 
+  state = {
+    logs: [],
+  };
+
+  componentDidMount() {
+    this.eventSource = new EventSource('/api/v1/activity_log');
+    this.eventSource.onmessage = (event) => {
+      this.setState({ logs: [...this.state.logs, JSON.parse(event.data)] });
+    };
+  }
+
+  componentWillUnmount() {
+    if (this.eventSource) {
+      this.eventSource.close();
+    }
+  }
+
   render () {
-    return <div>Hello world</div>;
+    return <div>{this.state.logs.map(x => (<div>{JSON.stringify(x)}</div>))}</div>;
   }
 
 }

config/routes.rb

@@ -542,6 +542,8 @@ Rails.application.routes.draw do
         resources :confirmations, only: [:create]
       end
 
+      resource :activity_log, only: [:show], controller: 'activity_log'
+
       resource :instance, only: [:show] do
         resources :peers, only: [:index], controller: 'instances/peers'
         resources :rules, only: [:index], controller: 'instances/rules'