How to use one partial in different contexts - ruby-on-rails

Question

i am new to rails and try to do the following:
I would like, because i use Bootstrap, to have a partial for a input field, with it's label and a little icon i called symbol in this case.
Here is my view:
<%= form_for(#user, :class => "form-horizontal" ) do |f| %>
<fieldset>
<%= render 'shared/text_field', function: f, tag: :name, symbol: '<i class="icon-user"></i>' %>
<%= render 'shared/text_field', function: f, tag: :email, symbol: "#" %>
<%= render 'shared/password_field', function: f, tag: :password, symbol: '<i class="icon-log"></i>' %>
<%= render 'shared/password_field', function: f, tag: :password_confirmation, alt: "Passwort wiederholen", symbol: '<i class="icon-log"></i>' %>
<!-- SUBMIT -->
<%= f.submit "Anmeldung", :class => "btn btn-primary" %>
</fieldset>
<% end %>
Here a subpartial for normal input fields:
<%= render 'shared/bootstrap/input_field' %>
<% content_for :label do %>
<%= function.label tag, :class => "control-label", :for => "prependedInput" %>
<% end %>
<%content_for :symbol do %>
<%= raw(symbol) %>
<% end %>
<% content_for :field do %>
<%= function.text_field tag, :class => "input-xlarge", :id => "prependedInput", :size => "6" %>
<% end %>
(there is also a subpartial for password fields, basicly exchanging function.text_field with function.input_field)
And here is the input_field which is rendered:
<div class="control-group">
<%= yield :label %>
<div class="controls">
<div class="input-prepend">
<span class="add-on"><%= yield :symbol %> </span>
<%= yield :field %>
</div>
</div>
</div>
So my question is: how can i solve this Problem in a nice and easy way (this things happend while refactoring and it got even worse then better) and how can i make it work, because by now something like this happens: http://pastebin.com/bNsgT9AR so yield puts with each content_for the content and the content before into the place (except the last one)
It would be great to hear nice solutions from you, there has to be a so much nicer way as almost always in Rails.
Greetings form Germany ;)

Answer 1

As the author of The Rails View, I agree with Ben Taitelbaum's post on this and say that Formtastic is totally a great option for this kind of complexity.
With regards to the code you posted, as developers we want to avoid that kind of view writing across the board, as it ends up an unmanageable mess. There's too many files involved in editing a form, and at some point, some other dev will come in and overwrite our shared partial, not knowing where else it was used, to change the way a different form behaves. Any benefit of code reuse that we can get out of this kind of abstraction is completely obliterated by the potential for it to go sour very quickly with mutliple developers.
While Formtastic is great, I've also been using SimpleForm a lot in my recent apps, especially when I don't need the full power of Formtastic.
SimpleForm will handle your label, and it also supports i18n as well. With this it would be:
<%= simple_form_for #user do |f| %>
<%= f.input :name, :input_html => { :class => 'user-icon' } %>
<%= f.input :email %>
<%= f.input :password, :as => :password, :input_html => { :class => 'log-icon' } %>
<%= f.input :password_confirmation, :as => :password, :input_html => { :class => 'log-icon' } %>
<%= f.button :submit %>
<% end %>
Then in your I18n file, you can have:
en:
simple_form:
labels:
user:
username: 'User name'
password: 'Password'
password_confirmation: 'Password confirmation'
de:
simple_form:
labels:
user:
username: 'Benutzername'
password: 'Passwort'
password_confirmation: 'Passwort wiederholen'
And more as you need it. You can define your hints and placeholders in the i18n file as well.
Also, think about adding the icon as a CSS pseudo class :after, and do so for each class that you need to add in the code)
input.user-icon:after {
// image as background, positioned properly, etc etc
}
input.log-icon:after {
// image as background, positioned properly, etc etc
}
And that way, you can remove this kind of stuff from your ERB/HTML and put it where it belongs: In the CSS (presentation layer).

Answer 2

There's a great section on forms in The Rails View, where they recommend using FormBuilders for this type of thing (they also discuss formtastic, which is worth checking out).
The biggest lesson I got out of this book (and I can't recommend it enough!) is that it's important to keep views as simple as possible, since they tend to be the least fun part of a rails app to debug, especially as the app grows large. So from this perspective, I would want the view to be nice and simple, something like:
<%= semantic_form_for(#user) do |f| %>
<%= f.inputs do %>
<%= f.input :name, class: 'icon-user' %>
<%= f.input :email %>
<%= f.input :password %>
<%= f.input :password_confirmation %>
<% end %>
<%= f.buttons %>
<% end %>
Start with a nice readable view as the goal, and add the necessary helpers and formbuilders as needed for custom field types.
I'd recommend using I18n for setting the submit button text to be "Anmeldung" instead of hardcoding that as well.
I haven't used it, but you might want to check out formtastic-bootstrap for getting the integration you want..

Answer 3

I feel that's a bit too much generalization overhead for a simple input field.
Have you considered simply creating one shared input field partial and just passing in the field name (you named it tag) and the type of field (text_field or password_field) as parameters? I can see that your approach might be more general, but if you just need those two options for now, keep it as simple as possible.
Addition in reply to comment:
You can simply pass parameters to your partial like so:
<%= render 'shared/error_messages', object: f.object %>
And then use the the variables in your partial. in your case you could
<%= render 'shared/bootstrap/input_field', function: f, tag: :name, input_field_type: :text_field %>
and then in _input_field.html.erb
<div class="control-group">
<%= function.label tag, :class => "control-label", :for => "prependedInput" %>
...