Easy breadcrumbs for RESTful rails application

问题:

Is there any helper method (Other than default rails breadcrumb) that generates bread crumb navigation dynamically for a particular page without having to pass trivial parameters in RESTful application? That is, something that figures out automatically where the user is based on the REST url she is visiting?

For above mentioned implementation, we need to pass parameters like

REST

<% add_crumb(‘Profile’, user_profile_path) %>

Current page

<% add_crumb(“My Incoming Messages”, request.path) %>

There must be a way to generalize the code so that no parameter passing is required and should work for all RESTful apps with minimal configuration.

回答1:

Developed a simple hack. The method however assumes that there exists a method 'name' for every model object corresponding to each resource in the RESTful url. Whatever that the method 'name' returns is shown as breadcrumb name. If it is not found, it is shown as it is without making it link to anything. Separator used is '->' You may change it to suit your requirement.

def get_bread_crumb(url)
  begin
    breadcrumb = ''
    sofar = '/'
    elements = url.split('/')
    for i in 1...elements.size
      sofar += elements[i] + '/'
      if i%2 == 0
        begin
          breadcrumb += "<a href='#{sofar}'>"  + eval("#{elements[i - 1].singularize.camelize}.find(#{elements[i]}).name").to_s + '</a>'
        rescue
          breadcrumb += elements[i]
        end
      else
        breadcrumb += "<a href='#{sofar}'>#{elements[i].pluralize}</a>"
      end
      breadcrumb += ' -> ' if i != elements.size - 1
    end
    breadcrumb
  rescue
    'Not available'
  end
end

The method generally accepts request.url (Which given url of the current page) as the parameter. The method purposefully accepts the url for customization purposes. To generate the breadcrumb, simply add following code in your view -

<%= get_bread_crumb(request.url) %>

For the url /ideabox/2/idea/1, the bread crumb looks like

alt text http://www.imagechicken.com/uploads/1234855404069992300.png

Excuse me if code quality is not that great. I'm sure this code can be re-factored but I'm also sure you would be able to do that before using it.

Thanks.

回答2:

The solution provided by chirantan is great. If you need breabcrumbs for namespaced controller and need to change the breadcrumbs depending on the namespace as well then try this. This is not perfect but refactor it as you need. It works for my project.

Define a new helper: navigation_helper.rb

module NavigationHelper

  def navigation_add(title, url, namespace)

    if defined? @@namespace and !@@namespace.nil? and @@namespace == namespace
      @@navigation ||= []
    else
      @@navigation = []
    end

    @@navigation << {title: title, url: url} unless title == "Home"

    new_nav = []
    @@navigation.each do |hash|
      new_nav.push hash
      if hash[:title].to_s == title.to_s
        break
      end
    end

    @@navigation = new_nav
    @@navigation.uniq!
    @@namespace = namespace
  end

  def render_navigation
    if (request.path_parameters[:controller].sub('/', '::_').camelize + 'Controller').classify.constantize.action_methods.to_a.include? 'index'
      navigation_add controller_name.camelize.to_s, request.path_parameters.merge({action: 'index'}).except(:id), params[:controller].include?('/') ? params[:controller].split("/").first : nil
    end
    if defined? @@navigation
      render partial: 'navigation/navigation', locals: { navs: @@navigation, namespace: @@namespace }
    else
      render text: ''
    end
  end
end

Then define a view for this helper _navigation.haml

- unless navs.blank?

  %ol.breadcrumb

    - navs.each_with_index do |nav, index|

      - if index == 0

        %li=link_to fa_icon('arrow-left', text: 'Go Back'), :back

        - unless namespace.nil?

          %li

            %h4.inline= request.fullpath.split('/')[1].gsub('-', '_').camelize

            = fa_icon('angle-double-right')

      %li= link_to_unless (nav[:title] == controller_name.camelize and action_name == 'index'),  fa_icon(nav[:title].downcase.singularize, text: nav[:title]), nav[:url]