Most of a web application is pretty standard CRUD. I need some data to be pushed to clients live as it's created. Is it worthwhile to run a separate, more lightweight stack (such as Sinatra or EventMachine) for the AJAX?
If I run one stack, I'll have Rails' overhead. This might require more Rails processes / servers, so how do I communicate between these without database queries? ZeroMQ? Finally, is Rails suited to handle hundreds of concurrent connections?
If I run two stacks, I'll need to duplicate authorization logic.
Which methods have been successful for you?
In Rails 3 you can pretty easily hook in Rack apps using the new routing syntax and inheriting your controllers from ActionController::Metal or just defining self.call.
Have a read (or watch) of Railscast #222 and check out wycats' blog (see below for example excerpts).
You're already aware of the additional cases you'll need to handle if you go down this track, so make sure it's necessary before getting stuck into it. It's usually cheaper to drop $ on servers than on programmers - hardware and bandwidth is pretty cheap.
I personally feel like this falls under 'premature optimization' unless you app is already running and choking up with too much traffic.
A few nice examples:
# config/routes.rb
# Hook in Sinatra
root :to => HomeApp
# Write your own barebones Rack compatible code
match "/processes" => ProcessesApp
# Even specify an inline proc
match "/heartbeat", :to => proc {|env| [200, {}, ["App is running"]] }
# /lib/home_app.rb
class HomeApp < Sinatra::Base
get "/" do
"Hello from Sinatra"
end
end
# lib/processes_app.rb
class ProcessesApp
def self.call(env)
[200, {}, [`ps -axcr -o "pid,pcpu, pmem, time, comm"`]]
end
end
Related
I have a few Rack apps mounted within my routes.rb like so:
mount ImageVise, at: '/ivise'
mount ShaderApiV0, at: '/api/v0'
I am currently migrating from a spaghetti custom Rack stack to Rails, so it makes sense for me to keep those apps. I am noticing that the entire Rails middleware stack that is defined on the application (including my Rack::Cache setup) does function when I call a controller, but does not function when I call URLs controlled by those mini-apps. I am almost certain in Rails 4 it worked however.
For example, if I introduce a custom middleware like so:
class Mittel < Struct.new(:app)
def call(env)
a, b, c = app.call(env)
b['X-Kustom'] = 'olala'
[a,b,c]
end
end
config.middleware.insert_before Rack::Head, Mittel
I do see the X-Kustom response header when I request a URL that is driven by the Rails controllers, but I do not get it when I request one of the URLs controlled by the mounted mini-apps. Consequently conditional GET and things like that do not work etc. How can I make it work aside from replicating a third of the Rails middleware stack in config.rb and moving these apps mounts there?
Found it. Turns out I was mounting one of these apps in config.ru as well, under the same URL - and then of course the entire Rails stack gets bypassed, as it should be. Lesson learned.
I have a typical Rails REST Api written for a http consumers. However, it turns out they need web socket API because of the integration POS Machines.
The typical API looks like this;
class Api::Pos::V1::TransactionsController < ApplicationController
before_action :authenticate
def index
#transactions = #current_business.business_account.business_deposits.last(5)
render json: {
status: 200,
number: #transactions.count,
transactions: #transactions.as_json(only: [:created_at, :amount, :status, :client_card_number, :client_phone_number])
}
end
private
def request_params
params.permit(:account_number, :api_key)
end
def authenticate
render status: 401, json: {
status: 401,
error: "Authentication Failed."
} unless current_business
end
def current_business
account_number = request_params[:account_number].to_s
api_key = request_params[:api_key].to_s
if account_number and api_key
account = BusinessAccount.find_by(account_number: account_number)
if account && Business.find(account.business_id).business_api_key.token =~ /^(#{api_key})/
#current_business = account.business
else
false
end
end
end
end
How can i serve the same responses using web-sockets?
P.S: Never worked with sockets before
Thank you
ActionCable
I would second Dimitris's reference to ActionCable, as it's expected to become part of Rails 5 and should (hopefully) integrate with Rails quite well.
Since Dimitris suggested SSE, I would recommend against doing so.
SSE (Server Sent Events) use long polling and I would avoid this technology for many reasons which include the issue of SSE connection interruptions and extensibility (websockets allow you to add features that SSE won't support).
I am almost tempted to go into a rant about SSE implementation performance issues, but... even though websocket implementations should be more performant, many of them suffer from similar issues and the performance increase is often only in thanks to the websocket connection's longer lifetime...
Plezi
Plezi* is a real-time web application framework for Ruby. You can either use it on it's own (which is not relevant for you) or together with Rails.
With only minimal changes to your code, you should be able to use websockets to return results from your RESTful API. Plezi's Getting Started Guide has a section about unifying the backend's RESTful and Websocket API's. Implementing it in Rails should be similar.
Here's a bit of Demo code. You can put it in a file called plezi.rb and place it in your application's config/initializers folder...
Just make sure you're not using any specific Servers (thin, puma, etc'), allowing Plezi to override the server and use the Iodine server, and remember to add Plezi to your Gemfile.
class WebsocketDemo
# authenticate
def on_open
return close unless current_business
end
def on_message data
data = JSON.parse(data) rescue nil
return close unless data
case data['msg']
when /\Aget_transactions\z/i
# call the RESTful API method here, if it's accessible. OR:
transactions = #current_business.business_account.business_deposits.last(5)
write {
status: 200,
number: transactions.count,
# the next line has what I think is an design flaw, but I left it in
transactions: transactions.as_json(only: [:created_at, :amount, :status, :client_card_number, :client_phone_number])
# # Consider, instead, to avoid nesting JSON streams:
# transactions: transactions.select(:created_at, :amount, :status, :client_card_number, :client_phone_number)
}.to_json
end
end
# don't disclose inner methods to the router
protected
# better make the original method a class method, letting you reuse it.
def current_business
account_number = params[:account_number].to_s
api_key = params[:api_key].to_s
if account_number && api_key
account = BusinessAccount.find_by(account_number: account_number)
if account && Business.find(account.business_id).business_api_key.token =~ /^(#{api_key})/
return (#current_business = account.business)
end
false
end
end
end
Plezi.route '/(:api_key)/(:account_number)', WebsocketDemo
Now we have a route that looks something like: wss://my.server.com/app_key/account_number
This route can be used to send and receive data in JSON format.
To get the transaction list, the client side application can send:
JSON.stringify({msg: "get_transactions"})
This will result in data being send to the client's websocket.onmessage callback with the last five transactions.
Of course, this is just a short demo, but I think it's a reasonable proof of concept.
* I should point out that I'm biased, as I'm Plezi's author.
P.S.
I would consider moving the authentication into a websocket "authenticate" message, allowing the application key to be sent in a less conspicuous manner.
EDIT
These are answers to the questions in the comments.
Capistrano
I don't use Capistrano, so I'm not sure... but, I think it would work if you add the following line to your Capistrano tasks:
Iodine.protocol = false
This will prevent the server from auto-starting, so your Capistrano tasks flow without interruption.
For example, at the beginning of the config/deploy.rb you can add the line:
Iodine.protocol = false
# than the rest of the file, i.e.:
set :deploy_to, '/var/www/my_app_name'
#...
You should also edit your rakefile and add the same line at the beginning of the rakefile, so your rakefile includes the line:
Iodine.protocol = false
Let me know how this works. Like I said, I don't use Capistrano and I haven't tested it out.
Keeping Passenger using a second app
The Plezi documentation states that:
If you really feel attached to your thin, unicorn, puma or passanger server, you can still integrate Plezi with your existing application, but they won't be able to share the same process and you will need to utilize the Placebo API (a guide is coming soon).
But the guide isn't written yet...
There's some information in the GitHub Readme, but it will be removed after the guide is written.
Basically you include the Plezi application with the Redis URL inside your Rails application (remember to make sure to copy all the gems used in the gemfile). than you add this line:
Plezi.start_placebo
That should be it.
Plezi will ignore the Plezi.start_placebo command if there is no other server defined, so you can put the comment in a file shared with the Rails application as long as Plezi's gem file doesn't have a different server.
You can include some or all of the Rails application code inside the Plezi application. As long as Plezi (Iodine, actually) is the only server in the Plezi GEMFILE, it should work.
The applications will synchronize using Redis and you can use your Plezi code to broadcast websocket events inside your Rails application.
You may want to have a look at https://github.com/rails/actioncable which is the Rails way to deal with WebSockets, but currently in Alpha.
Judging from your code snippet, the client seems to only consume data from your backend. I'm skeptical whether you really need WebSockets. Ιf the client won't push data back to the server, Server Sent Events seem more appropriate.
See relevant walk-through and documentation.
I have a basic application running with ruby on rails. I use sqlite3 for development and postgres for production. I recently got access to Orchestrate.io and their student tier.
I would like to know how I could possibly use this with my application. I'm not even sure this is possible. My app is really simple (add-edit-delete). But it would be interesting to have a go at using the tools.
Mostly because I cannot find an efficient and free rails db text search.
You can definitely use Orchestrate as the backend for a Rails application.
A few different options:
The Orchestrate-Ruby client has both a method client & object client. Although the object client is still considered a work-in-progress, the method client provides a solid interface for connecting to the Orchestrate API.
Use an http library (such as rest-client or faraday) to make calls to the Orchestrate API.
There's also the Orchestrate-Rails gem. Your mileage may vary with this (last updated in April).
To use Orchestrate as the only backend (no postgres/mysql), I've found the best approach is to disable ActiveRecord:
When creating a new application, you can use -O to skip ActiveRecord:
rails new my_app -O
For existing applications:
1. Remove database adapter gems from your Gemfile (pg, mysql2, sqlite3, etc.)
2. Change your config/application.rb
Remove require 'rails/all line and require frameworks you want to use, for example:
require "action_controller/railtie"
require "action_mailer/railtie"
require "sprockets/railtie"
require "rails/test_unit/railtie"
3. Delete your database.yml file, db/schema.rb and migrations (if any)
4. Delete migration check in test/test_helper.rb
5. Delete any ActiveRecord configuration from your config/environments files (this is what is causing your error)
If you run into problems/errors, stack trace should give you sufficient information on what you need to change. You might for example have some ActiveRecord configuration in your initializers.
With the Orchestrate-Ruby client, you can define a model like so:
class Foo < Orchestrate::Collection
...
end
I'm still undecided on what the best approach for defining the Application object is, but one way I've done it is by making a global object with an initializer:
# /config/initializers/orchestrate.rb
$App = Orchestrate::Application.new(ENV['ORCHESTRATE_KEY']) # using dotenv gem
$App = Orchestrate::Application.new('your_key_here') # without dotenv
From here, you can then access the $App object in your controllers (to initialize the collection object):
class FoosController < ApplicationController
def index
#foos = Foo.new($App, "foos").each
end
end
Leveraging model concerns might be a better way to share the Application object/API key between models. Or you could roll your own classes on top of the method client.
Hope this helps!
I'll be looking into how to accomplish this in a more 'Railsy' way.
EDIT: also, textacular is a ruby gem which provides full-text search and indexing for postgres
My app consists of two rails servers with mostly different concerns sitting behind a reverse proxy. Let's call them Server1 and Server2. Occasionally, Server1 needs to render a link to a url on Server2. Is there a good way to use Rails route helpers for this? Specifically in Rails 2? I came up with this:
ActionController::Routing::Routes.draw do |map|
# other routes omitted
map.with_options(:host => 'server2.example.com') do |add|
# create a named route for 'http://server2.example.com/thingies'
add.server2_thingies '/thingies', :controller => 'fake'
# create a named route for 'http://server2.example.com/thingies/combobulate'
add.enhance_server2_thingies '/thingies/combobulate', :controller => 'fake'
# create a named route for 'http://server2.example.com/mabobs/combobulate'
add.enhance_server2_mabobs '/mabobs/combobulate', :controller => 'fake'
# etc..
end
end
So then I can use server2_thingies_url and such in my views. This works, but it makes me feel like a bad person because there is no FakeController and I certainly have no intention of routing requests to it. I considered making helper methods and placing them in app/controllers/application_controller.rb, but a colleague made the argument that it is best to keep all route helpers in routes.rb, so things like rake routes will be accurate, for instance. Is there a better way?
I think I'd make a counter-argument to your colleague: if you're having to dirty up routes.rb with a "FakeController", then your rake routes is still not going to be accurate. In fact, I'd say that this is exactly the kind of thing that a helper was meant to help: it's taking logic that belongs purely in the view (link generation), and removing it from your view templates. Helpers are also easier to maintain and tweak.
Another advantage to the helper style is that if and when it's time to upgrade to Rails 3.x, the less hackish your routes.rb file is, the happier you will be - and that I can attest to from experience. :)
I'd just pass in :host to your foo_path or foo_url calls.
Seems cleaner than messing around with a FakeController
Let's say I have an image that does not reside in the normal location:
{appname}/public/images/unconventional.gif
But instead here:
{appname}/unconventional.gif
I understand this is a complete violation of Rails conventions, is immoral and you should never do this under any circumstances and, furthermore, why would I even suggest such a foolish thing?
Ok, now that we have that out of the way, assuming I am on Windows and therefore symbolic links are out of the question, how is it possible to set this up?
Rails does not serve these images, it lets the web server do that. You had best change the configuration of your web server to handle this scenario. If you use Apache, for example, it would fairly easy to set up with mod_rewrite.
Making Rails serve these images will be ugly, but it is possible if you provide a route in your routes.rb that matches /public/images/unconventional.gif, and if the file itself does not exist. For example:
map.connect "public/images/unconventional.gif",
:controller => "static_image_controller",
:action => "serve"
And then create a controller StaticImageController:
class StaticImageController < ApplicationController
def serve
image = File.read(File.join(Rails.root, "unconventional.gif"))
send_data image, :type => "image/gif", :disposition => "inline"
end
end
Warning: if you use the above concept, note that if you use input from the URL to decide which file to serve (with params[:file], for example), you need to thoroughly sanitize the input, because you are risking exposing your entire file system to the outside world.