OmbuLabs Blog

If you are interested in Ruby and Rails performance, you have definitely read articles by Nate Berkopec from Speedshop. At Ombu Labs we are big fans of his work, his Complete Guide to Rails Performance book and Slack community.

When Nate announced a series of public workshops I didn't hesitate and signed up as quickly as possible. Here are my notes from my experience at the workshop on October 17th.

Some time ago we wrote a couple of Tips for Writing Fast Rails. It was about time we wrote part two so here it is!

We recently spoke with Ryan Findley, Principal at Neomind Labs. We worked with his team to execute a Rails upgrade from 2.3 to 4.2 on one of their applications.

The internet is a wonderful place, but there will always be people that don't have good intentions when they visit our websites. That's why you need to be aware of the vulnerabilities that your application can have and how to avoid them. In this article I'll cover two common security problems in Rails applications (I'll probably make a second part since this is a very extensive topic).

This article is part of our Upgrade Rails series. To see more of them, click here.

This article will cover the most important aspects that you need to know to get your Ruby on Rails application from version 5.1 to 5.2.

Transcript:

Hello and welcome to the first OmbuCast by Ombu Labs. In this screencast we'll be taking a look at the derailed_benchmarks gem, and how you can use it to benchmark your Rails application and find, and hopefully fix bottlenecks in your code.

This article is part of our Upgrade Rails series. To see more of them, click here.

This article will cover the most important aspects that you need to know to get your Ruby on Rails application from version 5.0 to 5.1.

Today we are happy to announce the launch of our new microsite: Gemfile.lock Audit Tool - a tool created to allow users to check their Gemfile.lock for vulnerabilities in a quick and secure manner.

Last month was the fifth edition of the Rails Girls Buenos Aires event, and the third time Ombu Labs participated as a sponsor and part of the coaching team. This time it took place in the impressive offices of Google Argentina where 25 participants attended. All of them were very excited and motivated to start learning new skills.

This article is part of our Upgrade Rails series. To see more of them, click here.

This article will cover the most important aspects that you need to know to get your Ruby on Rails application from version 4.2 to 5.0.

We recently collaborated with Power Home Remodeling on a Rails upgrade for their self-described “monolith CRM/ERP application” and were able to speak to them about their experience with Ombu Labs.

With the release of Rails 5.2 just around the corner (Rails 5.2 RC1 is already available!), we will be taking a look at some of the upcoming changes to the ActiveRecord::Dirty module. If you're running Rails 5.1, you may have already seen some of the deprecation warnings related to the API changes contained in it. Most of them are behavior changes, and there are some new additions as well.

To better understand these modifications, we'll take a look at sample projects in Rails 5.1 and Rails 5.2.

This article is part of our Upgrade Rails series. To see more of them, click here.

This article will cover the most important aspects that you need to know to get your Ruby on Rails application from version 4.1 to 4.2.

This article is part of our Upgrade Rails series. To see more of them, click here.

This article will cover the most important aspects that you need to know to get your Ruby on Rails application from version 4.0 to 4.1.

This article is part of our Upgrade Rails series. To see more of them, click here.

A previous post covered some general tips to take into account for this migration. This article will try to go a bit more in depth. We will first go from 3.2 to 4.0, then to 4.1 and finally to 4.2. Depending on the complexity of your app, a Rails upgrade can take anywhere from one week for a single developer, to a few months for two developers.

This is the third article of our Upgrade Rails series. We will be covering the most important aspects that you need to know to update your Ruby on Rails application from version 3.1 to 3.2.

This is the second article of our Upgrade Rails series. We will be covering the most important aspects that you need to know to update your Ruby on Rails application from version 3.0 to 3.1. If you are in an older version, you can take a look at our previous article.

This article is the first of our Upgrade Rails series. We will be covering the most important aspects that you need to know to update your Ruby on Rails application from version 2.3 to 3.0.

Today we are happy to announce the launch of our first productized service: fastruby.io - Speedy Ruby on Rails Upgrades by Ombu Labs.

We are quite familiar with this sort of projects and decided to package it under its own domain. We have been doing Ruby on Rails upgrades since 2009, for our own products and client projects, and we are looking forward to shipping more of them.

I have been using the capybara-webkit gem for a while now since I first tried it out after making the switch from Capybara + Selenium.

Using capybara-webkit speeds up my Selenium tests due to its headless nature, and it's very straightforward. However, I had some trouble testing a Rails based React app.

In this post, I will explain how I worked around the issues that came up when trying to use capybara-webkit with React.

How many times did you come across a great gem you wanted to try out in a production console, like benchmark-ips or awesome-print?

Be it for performance or for readability, sometimes it's nice to be able to try out something new quickly without going through a pull request + deployment process. This is possible by modifying the $LOAD_PATH Ruby global variable and requiring the gem manually.

When working on a Rails project, you may have seen present? calls on ActiveRecord relationships. This might feel natural, mostly because present? exists on all objects via ActiveSupport, so you expect the relationship to respond to it, but it's actually not a very good idea. If all we want to do is check if the scope returns any results from the database, there are better ways than using present?.

Rails is a powerful framework. You can write a lot of features in a short period of time. In the process you can easily write code that performs poorly.

At Ombu Labs we like to maintain Ruby on Rails applications. In the process of maintaining them, adding features and fixing bugs, we like to improve the code and its performance (because we are good boy scouts!)

Here are some tips based on our experience.

Prefer where instead of select

When you are performing a lot of calculations, you should load as little as possible into memory. Always prefer a SQL query vs. an object's method call.

There are already quite a few guides in the wild to help with the upgrade of Rails 3.2 to Rails 4.0. The official Rails guide for upgrading from Rails 3.2 to 4.0 is very thorough. With the recent release of Rails 5.0, apps currently in production running Rails 3.2 should probably be updated to any stable Rails 4 release as soon as possible.

There is even an e-book about upgrading from Rails 3 to 4, which serves as a useful guide to make this upgrade easier, and also helps understand the advantages & disadvantages of this new (soon to be old) version.

However, if you're using any non-standard gems, you're mostly on your own. Some gems stopped being maintained before Rails 4 was released, as was the case with CanCan, a well known authorization library. After many open pull requests were left unmerged, CanCanCan was released. It is a community driven effort to have a semi-official fork of CanCan. It serves as a drop-in replacement for people who want to use CanCan after upgrading to Rails 4.

I'm a big fan of having small classes. I'm not a big fan of having huge specs for a small class/object. Every time I see an opportunity to DRY my specs, I take it.

Today I wrote a spec to make sure that we gracefully ignore SPAMmy contact requests in the Ombu Labs contact page. It initially looked like this:

test "gracefully ignores spammy requests with valid attributes" do
  @valid_contact = contacts(:two)
  attributes = @valid_contact.attributes
                             .merge(email_confirmation: @valid_contact.email)

  assert_no_difference("Contact.count") do
    post :create, contact: attributes, format: 'js'
  end

  assert_response :success
end

The new behavior adds a simple SPAM trap field that bots will usually fall for. If a bot is submitting the email_confirmation field (which is hidden by a CSS class), then it is SPAM and it gracefully ignores the request.

Sessions provide you a nice little data storage feature where the application does not need to get the information directly from the database. So you do not have to persist data in your database and can easily store info about the user on the fly. This is a nice way to enhance the user experience on your page.

Let's say that you want to show some users a new fancy sign up form and the rest the old form. If you store the version of the sign up form in a session variable, you don't need to persist this info in your database.

Recently, we started using Skylight in production for one of our clients' Rails applications, in an attempt to try to improve the performance of some of the more critical API endpoints.

Skylight reports on:

• Time taken per request
• Breakdown of time taken per SQL query
• Object allocations per request

I noticed an unusually large amount of allocated objects for one request:

This request would take anywhere from 400ms to 3000ms to respond, which is WAY too long.

It will come a time when you will have to decide whether to maintain a Rails project or not.

If you want to seriously consider it, you should follow these 10 steps:

1. Setup the development environment

Git clone the repository and try to start the server. Is the README clear enough? Can you follow the steps in the file and easily get started?

A lot of projects will have a README that is out of date and/or instructions that don't work right off the bat.

Most of the projects will define guidelines like these:

• Configure your config/database.yml
• Configure your .env file
• Setup the database rake db:create db:migrate db:seed
• Start the server rails server

The best projects will have a one-liner that will setup the entire environment for you.

Maybe in the past you stumbled over the two different approaches to setup your test variables. One way is the more programmatical approach by using instance variables, usually initialized in a before block.

When integrating Backbone.js in your Rails App, you might face the problem of the inability to verify the CSRF-Token.

The CSRF Protection secures your app with a token. Rails makes sure that the person who is interacting with your app is someone who started a session in your site, not some random attacker from another site. So you should not turn it off, unless you know what you are doing.

For more information on this Topic, check out the Rails Security Guide.

This problem occurs as soon as you are trying to send form data, without the CSRF-Token provided by Rails.

Started POST "/products" for 127.0.0.1 at 2015-12-16 10:06:05 -0300
Processing by ProductsController#create as JSON
  Parameters: {"product"=>{"name"=>"foo"}}
WARNING: Can't verify CSRF token authenticity
...
Completed 302 Found in 7.6ms (ActiveRecord: 0.8ms)

After this request, Rails will terminate your session and you will have to login again.

This problem is caused by your Backbone.js application, which is sending the data directly to the backend without providing the CSRF-Token.

To solve this problem you need to add the token to your Backbone request. One of the simplest solutions I came across is the following by Anton Shuvalov.

// https://github.com/shuvalov-anton/backbone-rails-sync
Backbone._sync = Backbone.sync;
Backbone.sync = function(method, model, options) {
  if (!options.noCSRF) {
    var beforeSend = options.beforeSend;

    // Set X-CSRF-Token HTTP header
    options.beforeSend = function(xhr) {
      var token = $('meta[name="csrf-token"]').attr('content');
      if (token) { xhr.setRequestHeader('X-CSRF-Token', token); }
      if (beforeSend) { return beforeSend.apply(this, arguments); }
    };
  }
  return Backbone._sync(method, model, options);
};

It grabs the CSRF-Token provided in the meta tags of your Rails application and sets it for the request header field X-CSRF-Token.

After adding this to the Backbone code, it works as expected.

Started POST "/products" for 127.0.0.1 at 2015-12-16 10:08:29 -0300
Processing by ProductsController#create as JSON
  Parameters: {"product"=>{"name"=>"foo"}}
...
Completed 200 OK in 40.6ms (Views: 0.6ms | ActiveRecord: 10.3ms)

default_scope is a method provided by ActiveRecord, which allows you to set a default scope (as its name implies) for all operations done on a given model. It can be useful for allowing soft-deletion in your models, by having a deleted_on column on your model and setting the default scope to deleted_on: nil