Flash messages appearing twice in rails

Question

My flash messages are appearing twice and my web research tells me this is due to render and redirect displaying the messages. I think I need to use flash.now[] or flash[] somewhere to sort this but I can't work out where it needs to go

guidelines_controller.rb

def update
  @guideline = Guideline.find(params[:id])

  respond_to do |format|
    if @guideline.update_attributes(params[:guideline])
      @guideline.update_attribute(:updated_by, current_user.id)
      format.html { redirect_to @guideline, notice: 'Guideline was successfully updated.' }
      format.json { head :no_content }
    else
      format.html { render action: "show" }
      format.json { render json: @guideline.errors, status: :unprocessable_entity }
    end
  end
end

layouts/application.html.erb

<div class="container">

    <% flash.each do |type, message| %>

        <div class="alert <%= flash_class type %>">
            <button class="close" data-dismiss="alert">x</button>
            <%= message %>
        </div>
    <% end %>
</div>

application_helper.rb

def flash_class(type)
  case type
  when :alert
    "alert-error"
  when :notice
    "alert-success"
  else
    ""
  end
end

guideline_controller.rb

def show
    @guideline = Guideline.find(params[:id])
    if @guideline.updated_by
     @updated = User.find(@guideline.updated_by).profile_name
   end

      if User.find(@guideline.user_id)
     @created = User.find(@guideline.user_id).profile_name
      end

    respond_to do |format|
      format.html # show.html.erb
      format.json { render json: @guideline }

    end
  end

Answer 1

You can do something like this in order to save some lines of code, and display the messages just once:

<%- if flash.any? %>
  <%- flash.keys.each do |flash_key| %>
    <%- next if flash_key.to_s == 'timedout' %>
    <div class="alert-message <%= flash_key %>">
      <a class="close" data-dismiss="alert" href="#"> x</a>
      <%= flash.discard(flash_key) %>
    </div>
  <%- end %>
<%- end %>

By using flash.discard, you show the flash message an avoid rendering twice

Answer 2

Just putting this here for anyone else having trouble.

I had flash messages appearing twice because I had something in application.html.erb telling my app to display flash messages, but I had previously generated views with rails generate scaffold posts etc, so that had automatically added the flash messages to all the views.

So the solution was to remove them from the views.

Here's a great tutorial that demonstrates removal for just one model/view

So basically, if you have something like this in your application.html.erb:

<% if notice %>
  <p class="alert alert-success"><%= notice %></p>
<% end %>
<% if alert %>
  <p class="alert alert-danger"><%= alert %></p>
<% end %>

Then simply remove the equivalent from each of the views. I.e. remove this line from the top of each view

<p id="notice"><%= notice %></p>