MetaPresenter is a Ruby gem for writing highly focused and testable Rails view presenter classes. For each controller/action pair you get a presenter class in app/presenters
that you can use in your views with presenter.method_name
. This helps you decompose your helper logic into tight, easily testable classes.
Installation
1. Add this line to your application's Gemfile
gem 'meta_presenter'
2. Bundle from the command line
bundle install
3. Include MetaPresenter::Helpers in ApplicationController
class ApplicationController < ActionController::Base
include MetaPresenter::Helpers
end
# mailers are supported too
class ApplicationMailer < ActionMailer::Base
include MetaPresenter::Helpers
end
Setup
1. Create an ApplicationPresenter
ApplicationPresenter methods can be used anywhere in the app. This example makes presenter.page_title
and presenter.last_login
accessible from all views.
# app/presenters/application_presenter.rb
class ApplicationPresenter < MetaPresenter::BasePresenter
def page_title
"My App"
end
def last_login
# controller methods are available to
# presenters in the same namespace
time = current_user.last_login_at
distance_of_time_in_words_to_now(time)
end
end
2. Create presenters for your controllers
This example makes presenter.tooltip(text)
available for all actions on PagesController
:
# app/presenters/pages_presenter.rb
class PagesPresenter < ApplicationPresenter
def tooltip(text)
content_tag(:p, text, class: "font-body1")
end
end
<!-- app/views/pages/about.html.erb -->
<h1>About</h1>
<p data-tipsy-content="<%= presenter.tooltip("Don't Be Evil") %>">Gloogle</p>
3. Create presenters for specific actions
This example makes presenter.greeting
accessible from views. It also delegates undefined methods to current_user
, so presenter.email
would call current_user.email
:
# app/presenters/pages/home_presenter.rb
class Pages::HomePresenter < PagesPresenter
# can also delegate specific methods. ex:
# delegate :email, :last, to: :current_user
delegate_all_to = :current_user
def greeting
"Hello, #{name}"
end
end
<!-- app/views/pages/home.html.erb -->
<h1>Home</h1>
<p><%= presenter.greeting %></p>
<p>Last login <%= presenter.last_login %></p>
Example directory structure
Note that presenters mirror the namespace of controllers.
app/
controllers/
application_controller.rb
pages_controller.rb
presenters/
application_presenter.rb
pages_presenter.rb
pages/
home_presenter.rb
logs_presenter.rb
views
pages
home.html.erb
logs.html.erb
spec/ (or test/)
presenters/
application_presenter_spec.rb
pages_presenter_spec.rb
pages/
home_presenter_spec.rb
logs_presenter_spec.rb
Aliasing the presenter methods
If you want to customize the presenter
method you can specify a shorthand by adding an alias_method to your controller or mailer:
class ApplicationController < ActionController::Base
including MetaPresenter
# So convenient!
alias_method :presenter, :pr
end
Requirements
MetaPresenter supports Ruby >= 3.0.0 and ActionPack/ActionMailer >= 6, or >= 7.0.1 for Rails 7 (7.0.0 has a bug)
Links
Specs
To run the specs for the currently running Ruby version, run bundle install
and then bundle exec rspec
. To run specs for every supported version of ActionPack, run bundle exec appraisal install
and then bundle exec appraisal rspec
.
Gem release
Make sure the specs pass, bump the version number in meta_presenter.gemspec, build the gem with gem build meta_presenter.gemspec
. Commit your changes and push to Github, then tag the commit with the current release number using Github's Releases interface (use the format vx.x.x, where x is the semantic version number). You can pull the latest tags to your local repo with git pull --tags
. Finally, push the gem with gem push meta_presenter-version-number-here.gem
.
TODO High-Priority
- Add a
rake meta_presenter:install
that generates the scaffolding for you - Make sure directions are clear for manually creating presenters
TODO
- create an example app and link to the repo for it in this README
- add support for layout-level presenters
Contributing
- Fork it
- Create your feature branch (
git checkout -b feature/my-new-feature
) or bugfix branch (git checkout -b bugfix/my-helpful-bugfix
) - Commit your changes (
git commit -am 'Add some feature'
) - Push to the branch (
git push origin feature/my-new-feature
) - Make sure specs are passing (
bundle exec rspec
) - Create new Pull Request
Running the specs
To run specs against different versions of Rails:
bundle exec appraisal install #install dependencies for each ruby version
bundle exec appraisal rails6 rspec #run rails 6 specs on current Ruby
bundle exec appraisal rails7 rspec #run rails 7 specs on current Ruby
License
See the LICENSE file.