link_to_unless_current fails when processing forms with error messages in it with restfull routes

Question

Hello,

does anyone know how to prevent the failing mechanism of link_to_unless_current?

f.e.: I have my page navigation with

link_to_unless_current "new task", new_task_path

When I click on the link, i come to the new taks path form... And no link is created -> ok. Then I put incorrect values in the form and submit.

The TasksController processes the "create" action, the validation for the ActiveRecord-model fails because of the incorrect data and the controller renders the "new" action (and includes the error messages for the model).

class TasksController < ApplicationController
    def create
        @task = Task.new(params[:task])

        if @task.save
            flash[:notice] = 'task was successfully created.'
            redirect_to(tasks_url)
          else
            render :action => "new"
        end
    end
end

But here the link gets created! -> Because of the difference between the urls:

  link path = new_task_path

but

  posted path = tasks_path with :method => :post

Does anybody know how to cleanly solve this problem?

Thanks

Answer 1

You can do it with link_to_unless instead of link_to_unless_current:

link_to_unless(controller_name == 'tasks' && 
                 (action_name == 'new' || action_name == 'create'), 
               new_task_path)

Answer 2

Having a quick look at the source for link_to_unless_current...

...it makes use of current_path? such that you should be able to do something like this:

In a helper...

def current_page_in?(*pages)
  pages.select {|page| current_page?(page)}.compact.any? 
end

... and then in your view, you can just supply an array of either named_routes or hashes like Shadwell's answer above.

<%= link_to_unless(current_page_in?(new_thing_path, things_path), "add a thing") %>

You get the idea...

UPDATED

Had a think about this... and it'd be great if you could just use it like you'd hoped that the original method worked. Here we compare the supplied named route (or controller + action hash) with the current page AND its referrer.

def current_page_or_referrer_in(options)
  url_string = CGI.unescapeHTML(url_for(options))
  request = @controller.request
  # We ignore any extra parameters in the request_uri if the
  # submitted url doesn't have any either.  This lets the function
  # work with things like ?order=asc
  if url_string.index("?")
    request_uri = request.request_uri
    referrer_uri = request.referrer
  else
    request_uri = request.request_uri.split('?').first
    referrer_uri = request.referrer.split('?').first
  end

  #referrer_uri always has full path (protocol, host, port) so we need to be sure to compare apples w apples
  if url_string =~ /^\w+:\/\//
    ["#{request.protocol}#{request.host_with_port}#{request_uri}", referrer_uri].include?(url_string)
  else
    referrer_uri = referrer_uri.gsub(request.protocol, '').gsub(request.host_with_port, '')
    [request_uri, referrer_uri].include?(url_string)
  end
end

The beauty is that it now lets you just do this (from your example):

<%= link_to_unless(current_page_or_referrer_in(new_task_path), "Add a task") %>

It'll then display if you're on new_task_path OR a page to which it has been sent (such as the create page