CommandServiceObject
Rails Generator for command service object.
Theory:
Command Design Pattern consists of Command Object and Service Object (Executor), Command object is responsible for containing Client requests and run input validations on it to ensure that the request is valid and set default values, then Service Object applies the business logic on that command.
Implementation:
Service consists of several objects { Command Object Usecase Object And Error Object (business logic error) }.
- Command Object: the object that responsible for containing
Clientrequests and run input validations it's implemented using Virtus gem and can useactiverecordfor validations and it's existed undercommandsdir. - Usecase Object: this object responsible for executing the business logic, Every
usecaseshould execute one command type only so that command name should be the same as usecase object name, usecase object existed under 'usecases` dir. - Error Object: business logic errors existed user
errorsdir inside the service dir.
Result Object:
In case of successful or failure ApplicationService the responsible object for all services will return service_result object this object contain value! method containing successful call result, and errors method containing failure errors objects.
You can check if the result successful or not by using
ok?method.
Installation
Add this line to your application's Gemfile:
gem 'command_service_object'
And then execute:
$ bundle
Or install it yourself as:
$ gem install command_service_object
Usage
$ rails g service [service_name] [usecases usecases]
Example
$ rails g service user create update delete
output
create app/services/user_service
create app/services/user_service/usecases
create app/services/user_service/commands
create app/services/user_service/errors
create app/services/user_service/usecases/create.rb
create app/services/user_service/commands/create.rb
create app/services/user_service/usecases/update.rb
create app/services/user_service/commands/update.rb
create app/services/user_service/usecases/delete.rb
create app/services/user_service/commands/delete.rb
then you can edit command params
you can read Virtus gem docs for more info.
# app/services/user_service/commands/create.rb module UserService::Commands class Create include Virtus.model
attribute :name, String
attribute :phone, String
attribute :age, Integer
end end
and then add your business logic
```ruby
# app/services/user_service/usecases/create.rb
module UserService::Usecases
class Create < ServiceBase
def call
# your business logic goes here
# keep call method clean by using private methods for Business logic
do_something
do_another_something
end
private
def do_something
# Business logic
# Don't catch errors ApplicationService will do that for you
raise Errors::CustomeError if ERROR
end
def do_another_something
# another business logic
end
end
end
usage from controller
class UsersController < ApplicationController
def create
cmd = UserService::Commands::Create.new(user_params)
result = ApplicationService.call(cmd)
if result.ok?
render json: result.value!.as_json, status: 201
else
render json: { message: result.error }, status: 422
end
end
end
Development
After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.
Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/adham90/command_service_object. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.
License
The gem is available as open source under the terms of the MIT License.
Code of Conduct
Everyone interacting in the CommandServiceObject project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.