...up 20160517112656 Migrate pages to page versions up 20160518112023 ********** NO FILE ********** When you tell Rails to roll back, it tries to roll back the latest change that was migrated. In...

...have the corresponding migration file for. Hence, it can not be rolled back and Rails aborts silently. This happens for example when you migrated on the master branch at some...

Before Rails 3.2.14, when supplying an invalid locale to I18n, it would fall back to its config.i18n.default_locale (which is :en by default). Eventually, this will be changed to raise...

...an error by default -- for now, it shows a deprecation warning. Since Rails 3.2.14 and 3.2.15 did not include security updates, you might not have applied them and probably now...

...port and the username (default root) and password (default msandbox). When working on a Rails project, you need to paste all of that into your config/database.yml. Connecting to a sandbox...

We upgraded a Rails 2 application to Rails 3.2 and Ruby 2.1, changed the mysql adapter from mysql to mysql2, but did not activitate the asset pipeline. Instead we used...

...ruby with something like user_ids = ActiveRecord::Base.connection.select_values(Message.select(:user_id).to_sql) # Rails 2 user_ids = Message.all.pluck(:user_id) # Rails 3+ User.where(:id => user_ids).update_all(:has...

Rails has the handy controller method send_file which lets us download files easily. We can decide whether the file should be downloaded (disposition: 'attachment') or shown in the browser...

...only want to compile when needed. This card shows what will cause Webpacker (the Rails/Webpack integration) to compile your assets. When you run a dev server While development it is...

...call any helper that accesses asset paths (e.g. javascript_pack_tag or image_tag), Rails will compile your entire assets within its process before that helper returns. This will cause...

If you are using Angular and want something like Rails' simple_format which HTML-formats a plain-text input into paragraphs and line breaks, this directive is for you.

I believe that when WEBrick has trouble bringing up your Rails application, the WEBrick component that is supposed to print you a pretty error message has a bug and sometimes...

...pointed to the actual problem. Possible causes discovered by looking at the logs A Rails plugin would require the sqlite3 gem, but that gem wasn't in the Gem bundle...

...which requires ApplicationController when loaded. When your ApplicationController requires later-loaded gems when loaded, Rails will not boot. Here is an example for an ApplicationController requiring Aegis::Controller from the...

...In this case aegis must be listed before resource_controller in your Gemfile or Rails will not boot...

Issue: You have an app using jsbundling-rails and esbuild. After deploy, the assets built by esbuild are missing in public/assets. Solution: Add app/builds to your git repo (by adding...

...all will run all RSpec examples and Cucumber features. The report will be written RAILS_ROOT/coverage/index.html. Here is what the task does in detail: Generates aggregated coverage of both RSpec...

Works with Rails 2 and Rails 3 Reports for app/**/*.rb and nothing else If called with an environment variable IGNORE_SHARED_TRAITS=true it ignores Modularity traits...

...you need to make a static web page and find yourself missing all your Rails comforts, take a look at StaticMatic. This works like an extremely stripped down version of...

...Rails, giving you HAML SASS helpers partials When done, everything is simply compiled to static HTML and CSS, so no need to install anything on your server. If you receive...

Note: In Rails 3+ you can use Array.wrap instead of the solution here. In the past you could use Array(...) or #to_a to turn an object into an array...

...you can copy the attached file to config/initializers or require it from a non-Rails project. You can now say: 5.listify # => [5] [5].listify # => [5] Note that this method no...

RSpec 1 (Rails 2) With the most recent spec_candy.rb helpers you can say: User.stub_any_instance(:foo => :bar) user = User.new user.foo # => :bar RSpec 2 (Rails 3) RSpec 2 comes with...

To reload a single-item association in Rails 5+, call #reload_ : post.reload_author In older Railses you can say post.author(true...

...with the following snippet: actors = movie.actors actors.build actors.unshift(actors.pop(1)) # won't work with Rails 4+ Because build_for_form creates new objects and appends them to the one-to...

...many association collection object you only have to reorder the collection objects. Sorting with Rails 3+ = form.fields_for :children, @parent.children.sort_by(&:name) do |fieldsform...

...look at the filter chain in specs. You can do it like that on Rails 2: controller.class.filter_chain.map(&:method) Note that we need to look at the controller's class since...

...objects to scope down to only some of them: controller.class.filter_chain.select(&:before?).map(&:method) For Rails 3, do it like this (warning, ugly!): controller._process_action_callbacks.select { |c| c.kind == :before }.map(&:filter)

...by calling #dup on it: user = User.find(3) user.freeze unfrozen_user = user.dup Notes for Rails 2 users There is a bug in Rails 2.3.x where duping an ActiveRecord instance...

...just upgraded to Bundler 10.0.10 you might get the following error when bringing up Rails: /usr/lib/ruby/1.9.1/psych.rb:148:in `parse': couldn't parse YAML at line 17 column 14 (Psych::SyntaxError...

...This is caused by Rails localization files (en.yml, de.yml, etc.) using symbols for various translation strings, and Bundler 10.0.10 defaults to a new YAML engine which cannot handle symbols.

Once Rails knows a given string is html_safe, it will never escape it. However, there may be times when you still need to escape it. Examples are some safe...

...to turn your string into an unsafe string to get the escaping love from Rails: embed = javascript_tag('var foo = 1337;') # This is an html_safe SafeBuffer embed.to_str # This...

...or from the public folder with javascript_include_tag. The subtle difference that tells rails how to build the path correctly is a single slash at the beginning of the...

...stylesheet in /assets you need to add it to the list of assets that Rails will precompile...