File: README — Documentation for gretel (5.0.1)

Handle breadcrumb trails... like a boss :)

(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: " %>:

Option	Description	Default
:style	How to render the breadcrumbs. Can be `:inline`, `:ol`, `:ul`, or `:bootstrap`. See below for more info.	`:inline`
:pretext	Text to be rendered before breadcrumb, e.g. `"You are here: "`.	None
:posttext	Text to be appended after breadcrumb, e.g. `"Text after breacrumb"`,	None
:separator	Separator between links, e.g. `" &rsaquo; "`.	`" &rsaquo; "`
:autoroot	Whether it should automatically link to the `:root` crumb if no parent is given.	True
:display_single_fragment	Whether it should display the breadcrumb if it includes only one link.	False
:link_current	Whether the current crumb should be linked to.	False
:link_current_to_request_path	Whether the current crumb should always link to the current request path. Note: This option will have no effect unless `:link_current` is set to `true`.	True
:semantic	Whether it should generate semantic breadcrumbs.	False
:id	ID for the breadcrumbs container.	None
:class	CSS class for the breadcrumbs container. Can be set to `nil` for no class.	`"breadcrumbs"`
:fragment_class	CSS class for the fragment link or span. Can be set to `nil` for no class.	None
:current_class	CSS class for the current link or span. Can be set to `nil` for no class.	`"current"`
:pretext_class	CSS class for the pretext, if given. Can be set to `nil` for no class.	`"pretext"`
:posttext_class	CSS class for the posttext, if given. Can be set to `nil` for no class.	`"posttext"`
:link_class	CSS class for the link, if given. Can be set to `nil` for no class.	None
:container_tag	Tag type that contains the breadcrumbs.	`:div`
:fragment_tag	Tag type to contain each breadcrumb fragment/link.	None
:aria_current	Value of `aria-current` attribute.	None
:link_data	Adds data attributes to breadcrumb	`nil`

Styles

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

Style	Description
`:inline`	Default. Renders each link by itself with `&rsaquo;` as the seperator.
`:ol`	Renders the links in `<li>` elements contained in an outer `<ol>`.
`:ul`	Renders the links in `<li>` elements contained in an outer `<ul>`.
`:bootstrap`	Renders the links for use in Bootstrap v3.
`:bootstrap4`	Renders the links for use in Bootstrap v4.
`:bootstrap5`	Renders the links for use in Bootstrap v5.
`:foundation5`	Renders the links for use in Foundation 5.

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">
  <%= breadcrumbs.structured_data(url_base: "https://example.com") %>
</script>

Or, you can infer url_base from request:

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

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.

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

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:

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

Thanks.

Contributors

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

See the list of contributors

And then

After using Gretel, you'll be like this