Rails - Nov 2005 - Helper or partial?

I often find myself not being able to choose if I should use a partial 
or a helper. They both get the job done but I want to know more about 
why it''s better to use one or the other in certain situations etc.

What do you use, and when?

-- 
Posted via http://www.ruby-forum.com/.

When I first saw helpers in the Todo list tutorial
http://manuals.rubyonrails.com/read/chapter/38#page113 I thought this is an
ugly solution

def display_items(ary)
result_string = ""
ary.each do |@item|
result_string << check_box("item", "done",
"onclick" => "
document.location.href=''/todo/toggle_check/#{@item.id}''")
+ " "
result_string << @item.description + " "
result_string << link_to("Edit", :action => "edit",
:id =>
@item.id<http://item.id>)
+ " "
result_string << link_to("Destroy",
{ :action => "destroy", :id => @item.id <http://item.id>
},
:confirm => "Are you sure you want to delete this entry:
#{@item.description
}")
result_string << "<BR />"
end
return result_string
end


Having all the ''result_string = '' and the ''+"
"'' is not very appealing.

- - - - - - -

In the very next section of the same Todo list tutorial
http://manuals.rubyonrails.com/read/chapter/38#page114 the solutions using
partials is much more appealing. It looks just like a template.

<%= check_box("item", "done", "onclick" =>
"
document.location.href=''/todo/toggle_check/#{@item.id}''")
%>
<%= @item.description %>
<%= link_to("Edit", :action => "edit", :id =>
@item.id <http://item.id>) %>
<%= link_to("Destroy", { :action => "destroy", :id
=> @item.id<http://item.id>},
:confirm => "Are you sure you want to delete this entry:
#{@item.description}")
%>
<br>

- - - - - - - -

I don''t think I would include things like check_box() or link_to() in a
helper. I would use a helper for something very small like the format
dollars helper in the Rails book p98.

module ApplicationHelper
def fmt_dollars(amt)
sprintf("$%0.2f",amt)
end
end

In this helper there is no appending to a string and no other helpers. It
just does a tiny task. The simple call in the template
<%fmt_dollars(%product.price) %> also indicates this is a method as
opposed to
a big chunk of partial template being inserted <%= render_partial
"display",
@item %>.

- Peter


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My very straightforward rule of thumb is this; use partials, and if  
they start to get horribly cluttered with lots of logic, change them  
to helpers. I also sometimes mix the two, so use helpers to contain  
logic and call out to partials to handle the actual rendering.

It''s all a style preference - I don''t like my
templates/partials full
of code as they just get unreadable and horrible to maintain.

On 13 Nov 2005, at 11:01, Per Djurner wrote:
> I often find myself not being able to choose if I should use a partial
> or a helper. They both get the job done but I want to know more about
> why it''s better to use one or the other in certain situations etc.
>
> What do you use, and when?
>
> -- 
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails

Dumb newbie question: Is it possible to output content from a helper
using something like ''h'', or do you have to build up the
string and
return it.

I''d been presuming you have to use a string because the helper might
not be view related.