Dynamic Paths in Helper

问题

I'm trying to create a helper method for my admin links. In quite a few views I have the code

<% if current_user %>
<%= link_to "Edit", edit_model_path(model) %>
<%= link_to "New", new_model_path %>
<%= link_to "Delete", model, :confirm => "You're a Noob",  :method
=> :delete %>
<% end %>

that only display these when logged in.

I would like to do something like this in their place

<%= admin_links(model) %>

and pass the current item into the application helper method

def admin_links(m)
 if current_user
  a = "#{link_to "edit" edit_m_path(m)}"
  a << "#{link_to "new" new_m_path}"
  a << "#{link_to "Delete", m, :confirm => "Your a Noob",  :method
=> :delete}"
 end
end

Or something of the like.

回答1:

basically you need to transform the class name of the model into something pointing to the correct path.

model_name = m.class.to_s.underscore

And then use it to call the appropriate path methods

link_to "edit", send("edit_#{model_name}_path", m)

As an aside, you don't need to put the link_tos in #{} because that function simply returns a string.

回答2:

Rails provides polymorphic routes to handle this problem: http://api.rubyonrails.org/classes/ActionDispatch/Routing/PolymorphicRoutes.html

= link_to "Edit", polymorphic_path(model), :method => :put

回答3:

I would use a partial for this - instead of a helper. Wherever you want to display these links in your views, simply render the partial:

<%= render :partial => "admin_links", :locals => { :model => model } %>

In _admin_links.html.erb just paste the original code:

<% if current_user %>
  <%= link_to "Edit", edit_model_path(model) %>
  <%= link_to "New", new_model_path %>
  <%= link_to "Delete", model, :confirm => "Your a Noob", :method => :delete %>
<% end %>

来源：https://stackoverflow.com/questions/1038770/dynamic-paths-in-helper