Rails 4 x Bootstrap 3：如何在控制器视图中生成错误警报

Question

I am using Rails 4 and Bootstrap 3 to build a CRUD web app.

I have an Invite model that lets users invite other users to join the app — and this is currently working.

This is my InvitesController :

class InvitesController < ApplicationController
  def create
    # some code
    if @invite.save
      # some code
      redirect_to some_path, notice: 'Invitation was successfully sent.'
    else
      redirect_to another_path, alert: 'Invitation could not be sent: please make sure you enter a valid email address and choose a role.'
    end
  end

end

Now, when a user successfully sends an invite, he is redirected to some path and gets a blue notice telling him precisely that.

However, when a user does not fill the Invite form correctly and the invite cannot be sent successfully, he is redirected to the same view (where the form is) and gets a yellow alert telling him there was an error in his form.

I would like to make the latter a red alert and I thought Bootstrap would allow me to do so by using redirect_to another_path, error: 'Invitation could not be sent: please make sure you enter a valid email address and choose a role.'

This did not work.

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UPDATE : What I am looking for here is a way to use the .alert-danger Bootstrap alert class, I don't want to simply change the color of my alert from yellow to red.

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What is the Rails / Bootstrap way of achieving what I need?

Answer 1

Here is the way I accomplish this:

First I create a helper method to translate the flash message type into bootstrap type

def bootstrap_class_for flash_type
  case flash_type.to_sym
    when :success
      "alert-success"
    when :error
      "alert-danger"
    when :alert
      "alert-warning"
    when :notice
      "alert-info"
    else
      flash_type.to_s
    end
end

Then I create a partial to render the messages stored in the flash session according to its type.

<% flash.each do |type, message| %>
  <div class="alert <%= bootstrap_class_for(type) %> fade in">
   <button class="close" data-dismiss="alert">×</button>
   <%= message.html_safe %>
  </div>
 <% end %> 

Answer 2

If you are using the twitter-bootstrap-rails gem there is a great helper already available for you to use that pretty much handles what you already have in place.

Gemfile

gem 'twitter-bootstrap-rails'

application.html.erb

<%= bootstrap_flash %>

The bootstrap_flash method is used inside your views and is where the flash will display. I prefer to put mine inside the application.html.erb file as it is used across most of my pages. Furthermore, this method pretty much does what Moustafa posted except the gem creator just did it for you.