A simple service layer pattern for plain old Ruby objects.
Yeah, yeah, yeah. Keep yer controllers skinny they always tell us. This is a lot easier to say than do in many cases. Our controllers are supposed to create that user, send them an invitation email, block them from access until they authenticate their email address, etc.
Porch allows you to move the code into a series of steps that execute simple methods on itself or within simple PORO objects.
This was inspired by LightService and the middleware chain by Sidekiq.
gem install porch
Your service object is simply a series of steps.
# app/services/registers_user.rb
require "porch"
module Services
class RegistersUser
include Porch::Organizer
attr_reader :attributes
def initialize(attributes)
@attributes = attributes
end
def register
with(attributes) do |chain|
chain.add CreateUser
chain.add SendWelcomeEmail
chain.add CreateBillingCustomer
end
end
end
end
You can then use your service in your controllers with the result that it returns from the chain.
# app/controllers/users_controller.rb
class UsersController < ApplicationController
def create
result = Services::RegistersUser.new(params[:user]).register
if result.success?
redirect_to dashboard_path(result.user), notice: "Welcome #{result.user.name}."
else
flash[:error] = result.message
render :new
end
end
end
You can define steps as PORO classes that respond to a call method.
# app/services/create_billing_customer.rb
require "stripe"
class CreateBillingCustomer
def call(context)
customer = Stripe::Customer.create email: context.email
User.find_by_email(context.email).update_attributes(billing_id: customer.id)
end
end
You can define steps as blocks on the organizer
# app/services/registers_user.rb
require "porch"
module Services
class RegistersUser
include Porch::Organizer
# ...
def register
with(attributes) do |chain|
# ...
chain.add do |context|
UserMailer.welcome(context.user).deliver_later
end
# ...
end
end
end
end
You can define steps as methods on the organizer.
# app/services/registers_user.rb
require "porch"
module Services
class RegistersUser
include Porch::Organizer
# ...
def register
with(attributes) do |chain|
# ...
chain.add :send_welcome_email
# ...
end
end
private
def send_welcome_email(context)
UserMailer.welcome(context.user).deliver_later
end
end
end
At any step, you can set the Porch::Context as a failure which will stop processing the remaining steps and set the Context as a failed context with an optional message.
class RegistersUser
include Porch::Organizer
# ...
def register
with(attributes) do |chain|
# ...
chain.add :send_welcome_email
# ...
end
end
private
def send_welcome_email(context)
context.fail! "Better luck next time!" if some_failure_condition?
UserMailer.welcome(context.user).deliver_later
end
end
result = RegistersUser.new(email: "[email protected]").register
if result.failure?
puts result.message # => "Better luck next time!"
end
Errors may be raised within your steps at any point and you may want to handle those errors gracefully.
You can use the rescue_from error handlers to handle various errors gracefully. The error handler will be called for the type of error or a descendent of the type of error.
You can rescue_from various errors with a method.
class RegistersUser
include Porch::Organizer
rescue_from [Net::SMTPAuthenticationError, Net::SMTPServerBusy], with: :smtp_error
private
def smtp_error(exception)
logger.error exception
end
end
You can rescue_from various errors with a block.
class RegistersUser
include Porch::Organizer
rescue_from Net::SMTPAuthenticationError do |exception|
logger.error exception
end
end
At any step, you can skip the remaining actions in the organizer. This stops the running of the remaining actions but the Porch::Context will still return a successful Porch::Context.
class RegistersUser
include Porch::Organizer
# ...
def register
with(attributes) do |chain|
# ...
chain.add :save_user
# ...
end
end
private
def save_user(context)
User.create context
context.skip_remaining! if sending_emails_disabled?
end
end
result = RegistersUser.new(email: "[email protected]").register
result.success? # => true
Porch comes with multiple ways that you can validate each step is setup correctly. It uses the DSL provided by dry-validation.
Several helper methods are included in the Porch::Context to guard against an invalid Porch::Context.
Porch::Context#guard can be used and if the validation fails, the Context will skip the remaining actions.
class SomeStep
def call(context)
context.guard_with_skipping { required(:email) }
# The rest of the action will not be performed and the rest of the actions will be
# skipped if the guard fails
end
end
Porch::Context#guard_with_failure (with a bang(!)) can be used and if the validation fails, the Context will be marked as a failure. The failure message for the Context will be set to be a comma-seperated list of the context errors that failed.
class SomeStep
def call(context)
context.guard_with_failure { required(:email) }
# The rest of the action will not be performed and the rest of the actions will be
# skipped and the action will be marked as failed if the guard fails
end
end
At any point, you can use the Porch::GuardRail::Guard helper method to validate any hash (including the Porch::Context).
hash = { email: "test@example" }
result = Porch::GuardRail::Guard.new(hash).against { required(:email).value(format?: RegEx::Email) }
result.success? # => false
result.errors # => { email: ["is invalid"] }
- Clone the repository
git clone https://github.com/jwright/porch - Create a feature branch
git checkout -b my-awesome-feature - Codez!
- Commit your changes (small commits please)
- Push your new branch
git push origin my-awesome-feature - Create a pull request
hub pull-request -b jwright:master -h jwright:my-awesome-feature
- Bump the VERSION in
lib/porch/version.rb - Commit changes and push to GitHub
- run
bundle exec rake release
This project is licensed under the MIT License.