Awesome

(TL;DR) Gretel is a Ruby on Rails plugin that makes it easy yet flexible to create breadcrumbs. It is based around the idea that breadcrumbs are a concern of the view, so you define a set of breadcrumbs in config/breadcrumbs.rb (or multiple files; see below) and specify in the view which breadcrumb to use. Gretel also supports semantic breadcrumbs (those used in Google results).

Have fun!

Installation

In your Gemfile:

gem "gretel"

And run:

$ bundle install

Example

Start by generating breadcrumbs configuration file:

$ rails generate gretel:install

Then, in config/breadcrumbs.rb:

# Root crumb
crumb :root do
  link "Home", root_path
end

# Issue list
crumb :issues do
  link "All issues", issues_path
end

# Issue
crumb :issue do |issue|
  link issue.title, issue
  parent :issues
end

At the top of app/views/issues/show.html.erb, set the current breadcrumb (assuming you have loaded @issue with an issue):

<% breadcrumb :issue, @issue %>

Then, in app/views/layouts/application.html.erb:

<%= breadcrumbs pretext: "You are here: ",
                separator: " &rsaquo; " %>

This will generate the following HTML (indented for readability):

<div class="breadcrumbs">
  <span class="pretext">You are here:</span>
  <a href="/">Home</a> &rsaquo;
  <a href="/issues">All issues</a> &rsaquo;
  <span class="current">My Issue</span>
</div>

Options

You can pass options to <%= breadcrumbs %>, e.g. <%= breadcrumbs pretext: "You are here: " %>:

Styles

These are the styles you can use with breadcrumbs style: :xx.

Or you can build the breadcrumbs manually for full customization; see below.

If you add other widely used styles, please submit a Pull Request so others can use them too.

More examples

In config/breadcrumbs.rb:

# Root crumb
crumb :root do
  link "Home", root_path
end

# Regular crumb
crumb :projects do
  link "Projects", projects_path
end

# Parent crumbs
crumb :project_issues do |project|
  link "Issues", project_issues_path(project)
  parent project # inferred to :project
end

# Child
crumb :issue do |issue|
  link issue.name, issue_path(issue)
  parent :project_issues, issue.project
end

# Recursive parent categories
crumb :category do |category|
  link category.name, category
  if category.parent
    parent category.parent # inferred to :category
  else
    parent :categories
  end
end

# Product crumb with recursive parent categories (as defined above)
crumb :product do |product|
  link product.name, product
  parent product.category # inferred to :category
end

# Crumb with multiple links
crumb :test do
  link "One", one_path
  link "Two", two_path
  parent :about
end

# Example of using params to alter the parent, e.g. to
# match the user's actual navigation path
# URL: /products/123?q=my+search
crumb :search do |keyword|
  link "Search for #{keyword}", search_path(q: keyword)
end

crumb :product do |product|
  if keyword = params[:q].presence
    parent :search, keyword
  else # default
    parent product.category # inferred to :category
  end
end

# Multiple arguments
crumb :multiple_test do |a, b, c|
  link "Test #{a}, #{b}, #{c}", test_path
  parent :other_test, 3, 4, 5
end

# Breadcrumb without link URL; will not generate a link
crumb :without_link do
  link "Breadcrumb without link"
end

# Breadcrumb using view helper
module UsersHelper
  def user_name_for(user)
    user.name
  end
end

crumb :user do |user|
  link user_name_for(user), user
end

# I18n
crumb :home do
  link t("breadcrumbs.home"), root_path
end

Building the breadcrumbs manually

You can use the breadcrumbs method directly as an array. It will return an array with the breadcrumb links so you can build the breadcrumbs HTML manually:

<% breadcrumbs.tap do |links| %>
  <% if links.any? %>
    You are here:
    <% links.each do |link| %>
      <%= link_to link.text, link.url, class: (link.current? ? "current" : nil) %> (<%= link.key %>)
    <% end %>
  <% end %>
<% end %>

If you use this approach, you lose the built-in semantic breadcrumb functionality. One way to add them back is to use JSON-LD structured data:

<script type="application/ld+json">
  <%= raw breadcrumbs.structured_data(url_base: "https://example.com").to_json %>
</script>

Or, you can infer url_base from request:

<script type="application/ld+json">
  <%= raw breadcrumbs.structured_data(url_base: "#{request.protocol}#{request.host_with_port}").to_json %>
</script>

Getting the parent breadcrumb

If you want to add a link to the parent breadcrumb, you can use the parent_breadcrumb view helper. By default it returns a link instance that has the properties #key, #text, and #url. You can supply options like autoroot: false etc.

If you supply a block, it will yield the link if it is present:

<% parent_breadcrumb do |link| %>
  <%= link_to "Back to #{link.text}", link.url %>
<% end %>

Nice to know

Access to view methods

When configuring breadcrumbs inside a crumb :xx do ... end block, you have access to all methods that are normally accessible in the view where the breadcrumbs are inserted. This includes your view helpers, params, request, etc.

Using multiple breadcrumb configuration files

If you have a large site and you want to split your breadcrumbs configuration over multiple files, you can create a folder named config/breadcrumbs and put your configuration files (e.g. products.rb or frontend.rb) in there. The format is the same as config/breadcrumbs.rb which is also loaded.

Loading breadcrumbs from engines

Breadcrumbs are automatically loaded from any engines' config/breadcrumbs.rb and config/breadcrumbs/**/*.rb. Breadcrumbs defined in your main app will override breadcrumbs from engines.

Inferring breadcrumbs

Breadcrumbs can be automatically inferred if you pass an instance of an object that responds to model_name (like an ActiveRecord model instance).

For example:

<% breadcrumb @product %>

is short for

<% breadcrumb :product, @product %>

Passing options to links

You can pass options to links to be used when you render breadcrumbs manually.

In config/breadcrumbs.rb:

crumb :something do
  link "My Link", my_path, title: "My Title", other: "My Other Option"
end

Example methods you can then use in the view:

breadcrumbs do |links|
  links.each do |link|
    link.title?              # => true
    link.title               # => "My Title"
    link.other?              # => true
    link.other               # => "My Other Option"
    link.nonexisting_option? # => false
    link.nonexisting_option  # => nil
  end
end

ARIA support

You can improve the accessibility of your page with the markup that specified in ARIA. Gretel supports generating aria-current attribute:

<% breadcrumb :issue, @issue %>
<%= breadcrumbs aria_current: "page" %>

This will generate the following HTML (indented for readability):

<div class="breadcrumbs">
  <a href="/">Home</a> &rsaquo;
  <a href="/issues">All issues</a> &rsaquo;
  <span class="current" aria-current="page">My Issue</span>
</div>

Documentation

• Full documentation
• Changelog
• Tutorial on using Gretel (Sitepoint)

Versioning

Follows semantic versioning.

Contributing

You are very welcome to help improve Gretel if you have suggestions for features that other people can use.

To contribute:

1. Fork the project
2. Create your feature branch (git checkout -b my-new-feature)
3. Make your changes
4. Add/Fix tests
5. Prepare database for testing: cd spec/dummy; rake db:migrate; rake db:test:prepare; cd ../..
6. Run rake to make sure all tests pass
7. Be sure to check in the changes to coverage/coverage.txt
8. Commit your changes (git commit -am 'Add new feature')
9. Push to the branch (git push origin my-new-feature)
10. Create new pull request

Thanks.

History

This repository had been a fork of lassebunk/gretel for a long time. However, due to some reasons, the maintenance of this repository was stopped and the official repository of gretel was transferred to WilHall/gretel, which is the fork of lassebunk/gretel. WilHall/gretel was then transferred to kzkn/gretel, where it continues to be maintained. During this time, kzkn/gretel was a fork of lassebunk/gretel, so lassebunk/gretel:master was selected by default when a pull request was made. This caused unnecessary confusion for contributors to gretel.

As mentioned earlier, lassebunk/gretel is no longer maintained. I have decided to detach the fork for the future of gretel, with all due respect to @lassebunk for creating gretel.

Contributors

Gretel was created by @lassebunk and was maintained by @WilHall. And it is maintained by @kzkn.

See the list of contributors

And then

Have fun!

Copyright (c) 2010-2020 Lasse Bunk, released under the MIT license