This gem is based on code from:
https://github.com/collectiveidea/interactor
https://github.com/michaelherold/interactor-contracts
https://github.com/tomdalling/value_semantics
I've used the 'interactor' gem for many years but developement on it had slowed down and I wanted more control over defining parameter constraints. 'interactor-contracts' provided a great model for this but it had dependencies on the dry-validation gem which at the time was still pre 1.0 and undergoing a lot of change but also moving very slowly. Due to the complexity of how 'interactor-contracts' dynamically generated schema clases (in combination with a bug in dry-rb) it seemed simpler to combine the code bases than tinker with complex internals that were subject to change anyway.
So this library is a mash up of 'interactor' and 'value_semantics' by @tomdalling, which provided a simpler, more elegant, basis for some basic parameter validation/coercion. For more complex schemas 'dry-validation' or 'parametric' can be laid on top.
Does not demonstrate many of the coercion and validation features.
class AuthenticateUser
include ServiceOperation::Base
param do
email :string
password :string
end
# unless optional, returns are checked via method after `#call` so these values will be fetched
# regardless of whether they're used and the operation will fail if they return nil.
returns do
user :user
token :string
user_id :integer
# the params (email and password) will also be returned
end
before do
# some filter logic (around and after are also implemented)
fail!(email: 'must be valid') if email !~ User::EMAIL_REGEXP
end
around do |op|
# start instrumentation
op.call
# stop instrumentation
end
after do
fail_unless_persisted?(user)
end
# this whole call method is actually unnecessary as :user is a required return value
# so commented out it would fail with { base: 'user cannot be blank' }
def call
fail!(message: 'authenticate_user.failure') unless user
end
private
def user
context.fetch { User.authenticate(email, password) }
end
def user_id
contex.fetch { user.id }
end
def token
context.fetch { user.secret_token }
end
end
class SessionsController < ApplicationController
def create
result = AuthenticateUser.call(session_params)
if result.success?
session[:user_token] = result.token
redirect_to result.user
else
flash.now[:message] = t(result.message)
render :new
end
end
private
def session_params
params.require(:session).permit(:email, :password)
end
end
Example parameter DSL:
params do
# coercion
user :user, coerce: -> (user) {user === User ? user : User.find_by_email(user) }
# optional values will be coerced but not fail if blank.
referrer :string, optional: true
# default values
subject :string, default: 'No Subject'
# Arrays with mixed types
numbers [:integer, :float], default: [1, 1.5, 2]
# The ValueSemantics DSL using mix of actual classes and types
activate Bool, default: false
timestamp Any(DateTime, Time), default: -> { Time.now }
media_assets ArrayOf(Jpg, Mp3)
payload Anything
end
docker-compose run app
or
docker-compose run app guard