I installed the 'websocket-rails' gem and after doing the default configuration I just created a JS dispatcher and I get a 404 error on chrome console.
This is my JS:
var dispatcher = new WebSocketRails('localhost:3000/websocket');
This is the message I get:
WebSocket connection to 'ws://localhost:3000/websocket' failed: Error during WebSocket handshake: Unexpected response code: 404
Everything else is as suggested by the first-steps-guide
events.rb
subscribe :test, :to => ChatServerController, :with_method => :test
controller/chat_server_controller.rb
class ChatServerController < WebsocketRails::BaseController
def initialize_session
# perform application setup here
controller_store[:message_count] = 0
end
def test
puts 'Hello'
end
end
There's one potential solution involving a gem dependency posted on github. But, if you look at the repo (151 open issues, 27 pull requests), it doesn't look like this gem is being actively maintained. The closed issues in 2016 are being closed by the same people who opened them.
You can probably make your application work by forcing websockets to use http by including a second parameter, set to false.
var Dispatcher = new WebSocketRails('localhost:3000/websocket', false);
I have concerns about how scalable using http polling will be and about the future of the websocket-rails gem. For me, it seems like the best way forward is to upgrade to Rails 5 and use Action Cable.
Related
What am I doing wrong?
I try to run example code from json-rpc documentation. Togather with EventMachine:
require 'json-rpc'
require 'thin'
class AsyncApp
include JsonRpc
AsyncResponse = [-1, {}, []].freeze
def call env
rpc_call(env)
end
def rpc_sum a, b
result = Rpc::AsyncResult.new
EventMachine::next_tick do
result.reply a + b
result.succeed
end
result
end
end
EM::run do
Thin::Server.start('0.0.0.0', 8999) do
map('/'){ run AsyncApp.new }
end
end
There is no error on this server console appears.
The result is on transport layer on the json-rpc client is:
500 Internal Server Error
I've try same client with jimson gem implememtation - it work fine but does not support EventMachine and async calls. (Show example if you know how it possible)
The problem was at default "welcome" page assigned to route "/".
I do not try to go with browser to "/", but only try to connect by rpc client.
Some how default "welcome" page route "/" rule is not overwrited by map("/"){...} rule.
The solution is rewrite route rule like this map("/rpc"){...}
I have a Rails Application with websocket-rails gem.
Inside my application there is a Daemon that I launch with rails runner MyDaemon.start
I'm using websocket-rails Synchronization, so my config/initializers/websocket_rails.rb looks like this:
WebsocketRails.setup do |config|
config.log_internal_events = false
config.standalone = false
config.synchronize = true
end
Inside MyDaemon, using synchronization, I can trigger event that will reach both my WebsocketRails::BaseController and my javascript WebSocketRails.
What I'm trying to do is to find a way to bind to events from my MyDaemon.
I've tried to implement a plain WebSocket client using both faye-websocket-ruby and websocket-client-simple, but after banging my head on my keyboard for some time, I figured out that there is some kind of "handshake" process using connection_id from the client_connected message. Basically none of the solutions provided in this other so question works for me.
I need to understand if inside my MyDaemon I can subscribe directly to some WebsocketRails callback, even inside an EventMachine, or how should I implement a Websocket Client in Ruby itself.
My last attempt to have a ruby client can be found in this gist, and this is a sample output:
ruby client.rb ws://localhost:3000/websocket
[:open, {"upgrade"=>"websocket", "connection"=>"Upgrade", "sec-websocket-accept"=>"zNTdGvxFKJeP+1PyGf27T4x2PGo="}]
JSON message is
[["client_connected", {"id"=>nil, "channel"=>nil, "user_id"=>nil, "data"=>{"connection_id"=>"4b7b91001befb160d17b"}, "success"=>nil, "result"=>nil, "token"=>nil, "server_token"=>nil}]]
client id is 4b7b91001befb160d17b
[:message, "[[\"client_connected\",{\"id\":null,\"channel\":null,\"user_id\":null,\"data\":{\"connection_id\":\"4b7b91001befb160d17b\"},\"success\":null,\"result\":null,\"token\":null,\"server_token\":null}]]"]
JSON message is
[["websocket_rails.ping", {"id"=>nil, "channel"=>nil, "user_id"=>nil, "data"=>{}, "success"=>nil, "result"=>nil, "token"=>nil, "server_token"=>nil}]]
Sending ["pong",{}]
[:message, "[[\"websocket_rails.ping\",{\"id\":null,\"channel\":null,\"user_id\":null,\"data\":{},\"success\":null,\"result\":null,\"token\":null,\"server_token\":null}]]"]
[:close, 1006, ""]
While the log of websocket-rails is:
I [2015-06-27 02:08:45.250] [ConnectionManager] Connection opened: #<Connection::2b3dddaf3ec4ed5e3550>
I [2015-06-27 02:08:45.251] [Dispatcher] Started Event: client_connected
I [2015-06-27 02:08:45.251] [Dispatcher] Name: client_connected
I [2015-06-27 02:08:45.251] [Dispatcher] Data: {"connection_id"=>"2b3dddaf3ec4ed5e3550"}
I [2015-06-27 02:08:45.251] [Dispatcher] Connection: #<Connection::2b3dddaf3ec4ed5e3550>
I [2015-06-27 02:08:45.251] [Dispatcher] Event client_connected Finished in 0.000174623 seconds
I [2015-06-27 02:09:05.252] [ConnectionManager] Connection closed: #<Connection::2b3dddaf3ec4ed5e3550>
I [2015-06-27 02:09:05.252] [Dispatcher] Started Event: client_disconnected
I [2015-06-27 02:09:05.252] [Dispatcher] Name: client_disconnected
I [2015-06-27 02:09:05.252] [Dispatcher] Connection: #<Connection::2b3dddaf3ec4ed5e3550>
I [2015-06-27 02:09:05.253] [Dispatcher] Event client_disconnected Finished in 0.000236669 seconds
Probably I'm missing somethig very stupid, so I'm here to ask your help!
You can use Iodine as a websocket client (I'm the author):
require 'iodine/http'
# prevents the Iodine's server from running
Iodine.protocol = :timer
# starts Iodine while the script is still running
Iodine.force_start!
options = {}
options[:on_open] = Proc.new {puts 'Connection Open'; write "Hello World!" }
options[:on_close] = Proc.new {puts 'Connection Closed'}
options[:on_message] = Proc.new {|data| puts "I got: #{data}" }
# connect to an echo server for demo. Use the blocking method:
websocket = Iodine::Http::WebsocketClient.connect "wss://echo.websocket.org/", options
websocket << "sending data"
sleep 0.5
websocket.close
As an aside note, reading around I noticed that the websocket-rails gem isn't being updated all that much. See this question
As an alternative, you can run websockets inside your Rails app by using the Plezi framework (I'm the author).
It's quite easy to use both frameworks at the same time on the same server. This way you can use your Rails model's code inside your Plezi Websocket controller.
Because Plezi will manage the websockets and Rails will probably render the 404 Not Found page, Plezi's routes will take precedence... but as long as your routes don't override each other, you're golden.
Notice that to allow both apps to run together, Plezi will force you to use Iodine server as your Rack server. To avoid this you can use the Placebo API and run Plezi on a different process.
You can read more the framework's README file.
so I'm using the Pusher Heroku Add-on for my application. The application has live notifications, so when a user receives a message he will see a pop up notification saying "new message". However, In production I am getting the below error:
Firefox can't establish a connection to the server at ws://ws.pusherapp.com/app/b1cc5d4f400faddcb40b?protocol=7&client=js&version=2.1.6&flash=false.
Reload the page to get source for: http://js.pusher.com/2.1/pusher.min.js
And here's the Pusher controller:
class PusherController < ApplicationController
protect_from_forgery :except => :auth # stop rails CSRF protection for this action
def auth
Pusher.app_id = ENV['PUSHER_APP_ID']
Pusher.key = ENV['PUSHER_KEY']
Pusher.secret = ENV['PUSHER_SECRET']
if current_user && params[:channel_name] == "private-user-#{current_user.id}"
response = Pusher[params[:channel_name]].authenticate(params[:socket_id])
render :json => response
else
render :text => "Not authorized", :status => '403'
end
end
end
And I'm using the figaro gem to push the keys to heroku.
What am I doing wrong?
Kind regards
JS
That looks like a problem with Javascript, rather than Rails
We've got pusher working very well with one of our production apps, and it works by firstly having the pusher gem installed, allowing you to call the pusher JS files from your layout:
#app/views/layouts/application.html.erb
<%= javascript_include_tag "http://js.pusher.com/2.1/pusher.min.js" %>
Rails
You may also wish to put the pusher initialization code into an initializer:
#config/initializers/pusher.rb
Pusher.url = ENV["PUSHER_URL"]
Pusher.app_id = ENV["PUSHER_APP_ID"]
Pusher.key = ENV["PUSHER_KEY"]
Pusher.secret = ENV["PUSHER_SECRET"]
This will ensure app-wide connectivity, rather than controller-specific (allowing for greater flexibility)
Firefox can't establish a connection to the server at ws://ws.pusherapp.com/app/b1cc5d4f400faddcb40b?protocol=7&client=js&version=2.1.6&flash=false.
Reload the page to get source for: http://js.pusher.com/2.1/pusher.min.js
This doesn't necessarily mean anything is wrong. it just means that an unsecured WebSocket connection couldn't be established. Pusher's fallback strategy should result in a successful connection being established via either HTTP fallback (HTTP or HTTPS) or via WSS (a secure WebSocket connection).
Failed connection attempts are logged as console errors. There's nothing that can be done about that.
To test this you can bind to connection events and ensure that you are indeed connecting. The pusher-js JavaScript logging will also help determine what's happening.
You can also try http://test.pusher.com/
For reasons similar to the ones in this discussion, I'm experimenting with messaging in lieu of REST for a synchronous RPC call from one Rails 3 application to another. Both apps are running on thin.
The "server" application has a config/initializers/amqp.rb file based on the Request / Reply pattern in the rubyamqp.info documentation:
require "amqp"
EventMachine.next_tick do
connection = AMQP.connect ENV['CLOUDAMQP_URL'] || 'amqp://guest:guest#localhost'
channel = AMQP::Channel.new(connection)
requests_queue = channel.queue("amqpgem.examples.services.time", :exclusive => true, :auto_delete => true)
requests_queue.subscribe(:ack => true) do |metadata, payload|
puts "[requests] Got a request #{metadata.message_id}. Sending a reply..."
channel.default_exchange.publish(Time.now.to_s,
:routing_key => metadata.reply_to,
:correlation_id => metadata.message_id,
:mandatory => true)
metadata.ack
end
Signal.trap("INT") { connection.close { EventMachine.stop } }
end
In the 'client' application, I'd like to render the results of a synchronous call to the 'server' in a view. I realize this is a bit outside the comfort zone of an inherently asynchronous library like the amqp gem, but I'm wondering if there's a way to make it work. Here is my client config/initializers/amqp.rb:
require 'amqp'
EventMachine.next_tick do
AMQP.connection = AMQP.connect 'amqp://guest:guest#localhost'
Signal.trap("INT") { AMQP.connection.close { EventMachine.stop } }
end
Here is the controller:
require "amqp"
class WelcomeController < ApplicationController
def index
puts "[request] Sending a request..."
WelcomeController.channel.default_exchange.publish("get.time",
:routing_key => "amqpgem.examples.services.time",
:message_id => Kernel.rand(10101010).to_s,
:reply_to => WelcomeController.replies_queue.name)
WelcomeController.replies_queue.subscribe do |metadata, payload|
puts "[response] Response for #{metadata.correlation_id}: #{payload.inspect}"
#message = payload.inspect
end
end
def self.channel
#channel ||= AMQP::Channel.new(AMQP.connection)
end
def self.replies_queue
#replies_queue ||= channel.queue("reply", :exclusive => true, :auto_delete => true)
end
end
When I start both applications on different ports and visit the welcome#index view.
#message is nil in the view, since the result has not yet returned. The result arrives a few milliseconds after the view is rendered and is displayed on the console:
$ thin start
>> Using rack adapter
>> Thin web server (v1.5.0 codename Knife)
>> Maximum connections set to 1024
>> Listening on 0.0.0.0:3000, CTRL+C to stop
[request] Sending a request...
[response] Response for 3877031: "2012-11-27 22:04:28 -0600"
No surprise here: subscribe is clearly not meant for synchronous calls. What is surprising is that I can't find a synchronous alternative in the AMQP gem source code or in any documentation online. Is there an alternative to subscribe that will give me the RPC behavior I want? Given that there are other parts of the system in which I'd want to use legitimately asynchronous calls, the bunny gem didn't seem like the right tool for the job. Should I give it another look?
edit in response to Sam Stokes
Thanks to Sam for the pointer to throw :async / async.callback. I hadn't seen this technique before and this is exactly the kind of thing I was trying to learn with this experiment in the first place. send_response.finish is gone in Rails 3, but I was able to get his example to work for at least one request with a minor change:
render :text => #message
rendered_response = response.prepare!
Subsequent requests fail with !! Unexpected error while processing request: deadlock; recursive locking. This may have been what Sam was getting at with the comment about getting ActionController to allow concurrent requests, but the cited gist only works for Rails 2. Adding config.allow_concurrency = true in development.rb gets rid of this error in Rails 3, but leads to This queue already has default consumer. from AMQP.
I think this yak is sufficiently shaven. ;-)
While interesting, this is clearly overkill for simple RPC. Something like this Sinatra streaming example seems a more appropriate use case for client interaction with replies. Tenderlove also has a blog post about an upcoming way to stream events in Rails 4 that could work with AMQP.
As Sam points out in his discussion of the HTTP alternative, REST / HTTP makes perfect sense for the RPC portion of my system that involves two Rails apps. There are other parts of the system involving more classic asynchronous event publishing to Clojure apps. For these, the Rails app need only publish events in fire-and-forget fashion, so AMQP will work fine there using my original code without the reply queue.
You can get the behaviour you want - have the client make a simple HTTP request, to which your web app responds asynchronously - but you need more tricks. You need to use Thin's support for asynchronous responses:
require "amqp"
class WelcomeController < ApplicationController
def index
puts "[request] Sending a request..."
WelcomeController.channel.default_exchange.publish("get.time",
:routing_key => "amqpgem.examples.services.time",
:message_id => Kernel.rand(10101010).to_s,
:reply_to => WelcomeController.replies_queue.name)
WelcomeController.replies_queue.subscribe do |metadata, payload|
puts "[response] Response for #{metadata.correlation_id}: #{payload.inspect}"
#message = payload.inspect
# Trigger Rails response rendering now we have the message.
# Tested in Rails 2.3; may or may not work in Rails 3.x.
rendered_response = send_response.finish
# Pass the response to Thin and make it complete the request.
# env['async.callback'] expects a Rack-style response triple:
# [status, headers, body]
request.env['async.callback'].call(rendered_response)
end
# This unwinds the call stack, skipping the normal Rails response
# rendering, all the way back up to Thin, which catches it and
# interprets as "I'll give you the response later by calling
# env['async.callback']".
throw :async
end
def self.channel
#channel ||= AMQP::Channel.new(AMQP.connection)
end
def self.replies_queue
#replies_queue ||= channel.queue("reply", :exclusive => true, :auto_delete => true)
end
end
As far as the client is concerned, the result is indistinguishable from your web app blocking on a synchronous call before returning the response; but now your web app can process many such requests concurrently.
CAUTION!
Async Rails is an advanced technique; you need to know what you're doing. Some parts of Rails do not take kindly to having their call stack abruptly dismantled. The throw will bypass any Rack middlewares that don't know to catch and rethrow it (here is a rather old partial solution). ActiveSupport's development-mode class reloading will reload your app's classes after the throw, without waiting for the response, which can cause very confusing breakage if your callback refers to a class that has since been reloaded. You'll also need to ask ActionController nicely to allow concurrent requests.
Request/response
You're also going to need to match up requests and responses. As it stands, if Request 1 arrives, and then Request 2 arrives before Request 1 gets a response, then it's undefined which request would receive Response 1 (messages on a queue are distributed round-robin between the consumers subscribed to the queue).
You could do this by inspecting the correlation_id (which you'll have to explicitly set, by the way - RabbitMQ won't do it for you!) and re-enqueuing the message if it's not the response you were waiting for. My approach was to create a persistent Publisher object which would keep track of open requests, listen for all responses, and lookup the appropriate callback to invoke based on the correlation_id.
Alternative: just use HTTP
You're really solving two different (and tricky!) problems here: persuading Rails/thin to process requests asynchronously, and implementing request-response semantics on top of AMQP's publish-subscribe model. Given you said this is for calling between two Rails apps, why not just use HTTP, which already has the request-response semantics you need? That way you only have to solve the first problem. You can still get concurrent request processing if you use a non-blocking HTTP client library, such as em-http-request.
I'm currently hosting both my rails app and a faye-server app on Heroku. The faye server has been cloned from here (https://github.com/ntenisOT/Faye-Heroku-Cedar) and seems to be running correctly. I have disabled websockets, as they are not supported on Heroku. Despite the claim on Faye's site that:
"Faye clients and servers transparently support cross-domain communication, so your client can connect to a server on any domain you like without further configuration."
I am still running into this error when I try to post to a faye channel:
XMLHttpRequest cannot load http://MYFAYESERVER.herokuapp.com. Origin http://MYAPPURL.herokuapp.com is not allowed by Access-Control-Allow-Origin.
I have read about CORS and tried implementing some solutions outlined here: http://www.tsheffler.com/blog/?p=428 but have so far had no luck. I'd love to hear from someone who:
1) Has a rails app hosted on Heroku
2) Has a faye server hosted on Heroku
3) Has the two of them successfully communicating with each other!
Thanks so much.
I just got my faye and rails apps hosted on heroku communicating within the past hour or so... here are my observations:
Make sure your FAYE_TOKEN is set on all of your servers if you're using an env variable.
Disable websockets, which you've already done... client.disable(...) didn't work for me, I used Faye.Transport.WebSocket.isUsable = function(_,c) { c(false) } instead.
This may or may not apply to you, but was the hardest thing to track down for me... in my dev environment, the port my application is running on will be tacked onto the end of the specified hostname for my faye server... but this appeared to cause a failure to communicate in production. I worked around that by creating a broadcast_server_uri method in application_controller.rb that handles inclusion of a port when necessary, and then use that anywhere I spin up a new channel.
....
class ApplicationController < ActionController::Base
def broadcast_server
if request.port.to_i != 80
"http://my-faye-server.herokuapp.com:80/faye"
else
"http://my-faye-server.herokuapp.com/faye"
end
end
helper_method :broadcast_server
def broadcast_message(channel, data)
message = { :ext => {:auth_token => FAYE_TOKEN}, :channel => channel, :data => data}
uri = URI.parse(broadcast_server)
Net::HTTP.post_form(uri, :message => message.to_json)
end
end
And in my app javascript, including
<script>
var broadcast_server = "<%= broadcast_server %>"
var faye;
$(function() {
faye = new Faye.Client(broadcast_server);
faye.setHeader('Access-Control-Allow-Origin', '*');
faye.connect();
Faye.Transport.WebSocket.isUsable = function(_,c) { c(false) }
// spin off your subscriptions here
});
</script>
FWIW, I wouldn't stress about setting Access-Control-Allow-Origin as it doesn't seem to be making a difference either way - I see XMLHttpRequest cannot load http://... regardless, but this should still works well enough to get you unblocked. (although I'd love to learn of a cleaner solution...)
Can't say I have used Rails/Faye on Heroku but have you tried setting the Access-Control-Allow-Origin header to something like Access-Control-Allow-Origin: your-domain.com?
For testing you could also do Access-Control-Allow-Origin: * to see if that helps
Custom headers
Some services require the use of additional HTTP headers to connect to
their Bayeux server. You can add these headers using the setHeader()
method, and they will be sent if the underlying transport supports
user-defined headers (currently long-polling only).
client.setHeader('Authorization', 'OAuth abcd-1234');
Source: http://faye.jcoglan.com/browser.html
So try client.setHeader('Access-Control-Allow-Origin', '*');