...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...

...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...

...want to uninstall newer ones): bundle _1.0.10_ -v Bundler version 1.0.10 An example is rails 3.2, which freezes bundler at version ~> 1.0: Bundler could not find compatible versions for gem...

In Gemfile: rails (~> 3.2) was resolved to 3.2.0, which depends on bundler (~> 1.0) Current Bundler version: bundler (1.13.6) You can solve this with: gem install bundler -v 1.0.10

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...

...files at once. To activate this feature, set the multiple attribute: Or in a Rails view: <%= file_field_tag "images[]", multiple: true %> This works in IE10+. Make sure that the...

...incoming files into an array. Obviously this naming convention is not compatible with default Rails nested attribute setters, so you'll need to write a form model to adapt...

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...

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.

...code below is a rough equivalent to the simple_format helper that ships with Rails: function simpleFormat(str) { str = str.replace(/\r\n?/, "\n"); str = $.trim(str); if (str.length > 0) {

...str.replace(/\n\n+/g, ' '); str = str.replace(/\n/g, ' '); str = ' ' + str + ' '; } return str; } Unlike the Rails helper, this does not preserve whitespace. You probably don't care...

...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...

JavaScripts and CSS should be minified for production use. In Rails 3.1+ the asset pipeline will take care of this. Thus you're best off using an uncompressed version of...

...be easier and you will still get all the minification love once deployed. In Rails 2.3 and 3.0 you should at least embed external JavaScript libraries in minified form, using...

...false (intercepts invocation), whereas false&.class permits the invocation. &. might also remind you of Rails' Object#try. However, their scopes are different, and in Rails 4 nil-checking is only...

...route that only responds to a given format, here is how you do it: Rails 3 match 'sitemap.xml' => 'feeds#sitemap', :constraints => { :format => 'xml' }, :as => 'sitemap' Rails 2 map.sitemap 'sitemap.xml', :controller...

Katapult 0.3.0 brings Rails 5 and Ruby 2.5 support with a new design, plus a ton of smaller features, fixes and improvements. Features Generating a Rails 5.1.4 app on Ruby...

Remember how Rails 2 came with an awesome feature that broke all code using Time.now or Time.parse? This behavior is now the default for Rails 3. Disable it by adding...

Using Scenic, you can bring the power of SQL views to your Rails application without having to switch your schema format to SQL. Scenic provides a convention for versioning views...

Katapult was an endeavor to dramatically speed up starting a new Rails application. However, it turned out to save less time than expected, while requiring more time for maintenance than...

...code antiquated. Nevertheless, its architecture may remain an inspiration on how to use the Rails generators programmatically...

SSHKit 1.9.0 might fail with the following error, when trying to deploy a Rail application. Upgrading the gem to version 1.21.0 fixed the issue. Traceback (most recent call last...