Ruby On Rails - 重用错误消息部分视图

Question

Problem

I was trying to reuse the Error Message block in my Views.

Below was the block written in positions/_error_messages.html.erb

<% if @position.errors.any? %>
  <div id="error_explanation">
   <div class="alert alert-error">
     The form contains <%= pluralize(@position.errors.count, "error") %>.
   </div>
   <ul>
    <% @position.errors.full_messages.each do |msg| %>
    <li>* <%= msg %></li>
   <% end %>
   </ul>
 </div>
<% end %>

The problem was I have to created similar partial view in every Model which is kind of repeating the same code with different object ie @user, @client etc.

Remedy

I have created one erb in shared folder shared/_error_messages.html.erb and wrote the below code.

<% def error_message(active_object) %>
 <% if active_object.errors.any? %>
  <div id="error_explanation">
   <div class="alert alert-error">
    The form contains <%= pluralize(active_object.errors.count, "error") %>.
   </div>
   <ul>
    <% active_object.errors.full_messages.each do |msg| %>
     <li>* <%= msg %></li>
    <% end %>
   </ul>
  </div>
 <% end %>
<% end %>

and then in view file. positions/new.html.erb I wrote the below code

<div id="errorbox"> 
 <%= render "shared/error_messages" %>
 <%= error_message(@position) %>
</div>

It means now I can use the same code in all my Create and Update operations.

I want to know, Is that a correct way to do it? Or is there any other option?

Answer 1

No, defining methods in views is not correct way to do it. I think you should rather substitute @position from your first partial with local variable named in more generic way, for example object and render this partial with:

<%= render 'shared/error_messages', object: @position %>

which passes @position as local variable object to the partial.

Answer 2

<%= render partial: 'shared/error_messages', locals: {position: @position} %>

Now in your partial _error_messages.html.erb in the shared folder you can use the position variable.

Refer to http://api.rubyonrails.org/classes/ActionView/PartialRenderer.html for more help.

Answer 3

It's not the best way to do it. replace @position with something more generic like 'obj' (as an example) in your first block of code. So it will look like this.

<% if obj.errors.any? %>
<div id="error_explanation">
<div class="alert alert-error">
The form contains <%= pluralize(obj.errors.count, "error") %>.
</div>
<ul>
<% obj.errors.full_messages.each do |msg| %>
<li>* <%= msg %></li>
<% end %>
 </ul>
</div>
<% end %>

All you did there was replace @position with obj. Now take the above code, and put it inside your shared folder as '_error_messages.html.erb'

Now for every file where you need the error messages you can render the partial and replace obj with whatever instance variable is used in that file. (at this point you would replace any error message code in your files with the code below, depending on which instance variable you are using. examples below) in positions:

<%= render 'shared/error_messages', obj: @position %>

in user:

<%= render 'shared/error_messages', obj: @user %>

in client:

<%= render 'shared/error_messages', obj: @client %>

etc... the obj: @client #or any instance variable switches out the 'obj' of the partial and puts in the instance variable in it's place. Hope that helps!