启动 Rails 服务器的 Rails 真的很奇怪

Question

I just initiated a new rails app with Rails new, changed the default database settings into PostgresSQL. I start the server with bin/rails s and I get this weird

2016-04-21 05:00:33] INFO  WEBrick 1.3.1
[2016-04-21 05:00:33] INFO  ruby 2.1.3 (2014-09-19) [i686-linux]
[2016-04-21 05:00:33] INFO  WEBrick::HTTPServer#start: pid=12160 port=3000


Started GET "/socket.io/?EIO=3&transport=polling&t=LGtCFqz" for 10.0.2.2 at 2016-04-21 05:00:38 +0000

ActionController::RoutingError (No route matches [GET] "/socket.io"):
  actionpack (4.1.6) lib/action_dispatch/middleware/debug_exceptions.rb:21:in `call'
  actionpack (4.1.6) 

lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
  railties (4.1.6) lib/rails/rack/logger.rb:38:in `call_app'
  railties (4.1.6) lib/rails/rack/logger.rb:20:in `block in call'
  activesupport (4.1.6) lib/active_support/tagged_logging.rb:68:in `block in tagged'
  activesupport (4.1.6) lib/active_support/tagged_logging.rb:26:in `tagged'
  activesupport (4.1.6) lib/active_support/tagged_logging.rb:68:in `tagged'
  railties (4.1.6) lib/rails/rack/logger.rb:20:in `call'
  actionpack (4.1.6) lib/action_dispatch/middleware/request_id.rb:21:in `call'
  rack (1.5.5) lib/rack/methodoverride.rb:21:in `call'
  rack (1.5.5) lib/rack/runtime.rb:17:in `call'
  activesupport (4.1.6) lib/active_support/cache/strategy/local_cache_middleware.rb:26:in `call'
  rack (1.5.5) lib/rack/lock.rb:17:in `call'
  actionpack (4.1.6) lib/action_dispatch/middleware/static.rb:64:in `call'
  rack (1.5.5) lib/rack/sendfile.rb:112:in `call'
  railties (4.1.6) lib/rails/engine.rb:514:in `call'
  railties (4.1.6) lib/rails/application.rb:144:in `call'
  rack (1.5.5) lib/rack/lock.rb:17:in `call'
  rack (1.5.5) lib/rack/content_length.rb:14:in `call'
  rack (1.5.5) lib/rack/handler/webrick.rb:60:in `service'
  /usr/local/rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/webrick/httpserver.rb:138:in `service'
  /usr/local/rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/webrick/httpserver.rb:94:in `run'
  /usr/local/rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/webrick/server.rb:295:in `block in start_thread'

This line in the stack trace really concerns me:

Started GET "/socket.io/?EIO=3&transport=polling&t=LGtCFqz" for 10.0.2.2 at 2016-04-21 05:00:38 +0000

I had a websocket gem installed called em-websockets as well as the thin gem. I uninstalled both from Ruby but I still get this error.

source 'https://rubygems.org'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.1.6'
# postgres db
gem 'pg'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 4.0.3'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# Use CoffeeScript for .js.coffee assets and views
gem 'coffee-rails', '~> 4.0.0'
# See https://github.com/sstephenson/execjs#readme for more supported runtimes
# gem 'therubyracer',  platforms: :ruby

# Use jquery as the JavaScript library
gem 'jquery-rails'
# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.0'
# bundle exec rake doc:rails generates the API under doc/api.
gem 'sdoc', '~> 0.4.0',          group: :doc

# Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
gem 'spring',        group: :development

# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'

# Use unicorn as the app server
# gem 'unicorn'

# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development

# Use debugger
# gem 'debugger', group: [:development, :test]

This is my gemfile. It has nothing with websockets as far as I can tell. Does anyone have any insight on this?

Thank you.

Answer 1

For Anyone who is really interested to know what is really happening here.

This is not a Rails application issue.

Rails is running on port http://localhost:3000 by default.

Like Rails App, you may have another server (Ex: Gulp / NodeJS ) run on the same port 3000. This server has been stopped and you started Rails server on the port 3000 instead.

Now the funny part coming into play. One of your old server's client is still requesting to your old Gulp / NodeJS server, assuming that it is still on port 3000 ( but it is hitting Rails on port 3000 :) ).

Actually the client is requesting to Gulp / NodeJS server, in that port you have Rails app running.

socket.io is a realtime application that work well with NodeJS.

That is why you see these weird GET requests in your Rails logs.

GET "/socket.io/?EIO=3&transport=polling&t=LGtCFqz" => this is not supposed to come into Rails application

And you blame Rails application and think why this error is happening !!

What you can do is just make sure that all the browser tabs apart from Rails app, that connecting to 3000 is closed.

Answer 2

I rebooted and restarted the server in default rails(0.0.0.0:3000). It fixed itself.

Thanks for all the help.