TL;DR

I have no time to read tons of docs.
Just show me an example use case and I'll quickly craft something similar 😎.

— A lazy developer

# Any source code in the project.
def read_file_content(path)
  result = ReadFileContent.result(path: path)

  if result.success?
    ##
    # Service tried to read the file content and completed it.
    #
    result.data[:content] # File content.
  elsif result.failure?
    ##
    # Service tried to read file content but did NOT complete it due to some expected reason.
    #
    App.logger.warn { result.message.to_s }

    "" # Fallback value or any other reasonable fallback behavior.
  else # result.error?
    ##
    # Service NOT even tried to read file content due to a validation issue or exception.
    #
    App.logger.error { result.message.to_s }

    raise VerboseException, result.message.to_s # Self-explanatory exception or any other reasonable fallback behavior.
  end
end

Standard

require "convenient_service"

Rails

require "active_model" # NOTE: Minimal `active_model` version - `5.2.0`.

require "convenient_service"

ConvenientService::Dependencies.require_assigns_attributes_in_constructor_using_active_model_attribute_assignment
ConvenientService::Dependencies.require_has_attributes_using_active_model_attributes
ConvenientService::Dependencies.require_has_j_send_result_params_validations_using_active_model_validations

Dry

require "dry-initializer" # NOTE: Minimal `dry-initializer` version - `3.0.0`.
require "dry-validation" # NOTE: Minimal `dry-validation` version - `1.5.0`.

require "convenient_service"

ConvenientService::Dependencies.require_assigns_attributes_in_constructor_using_dry_initializer
ConvenientService::Dependencies.require_has_result_params_validations_using_dry_validation

Custom

require "active_model" # NOTE: Minimal `active_model` version - `5.2.0`.
require "dry-initializer" # NOTE: Minimal `dry-initializer` version - `3.0.0`.
require "awesome_print" # NOTE: Minimal `awesome_print` version - `1.0.0`.

require "convenient_service"

ConvenientService::Dependencies.require_has_j_send_result_params_validations_using_active_model_validations
ConvenientService::Dependencies.require_assigns_attributes_in_constructor_using_dry_initializer
ConvenientService::Dependencies.require_rescues_result_unhandled_exceptions
ConvenientService::Dependencies.require_awesome_print_inspect if Rails.env.development? || Rails.env.test?

Standard

module ApplicationService
  module Config
    include ConvenientService::Concern

    included do
      include ConvenientService::Standard::Config
    end
  end
end

Rails

module RailsService
  module Config
    include ConvenientService::Concern

    included do
      include ConvenientService::Standard::Config

      concerns do
        use ConvenientService::Plugins::Common::AssignsAttributesInConstructor::UsingActiveModelAttributeAssignment::Concern
        use ConvenientService::Plugins::Common::HasAttributes::UsingActiveModelAttributes::Concern
        use ConvenientService::Plugins::Service::HasJSendResultParamsValidations::UsingActiveModelValidations::Concern
      end

      middlewares :initialize do
        use ConvenientService::Plugins::Common::AssignsAttributesInConstructor::UsingActiveModelAttributeAssignment::Middleware
      end

      middlewares :result do
        insert_before \
          ConvenientService::Plugins::Service::CanHaveConnectedSteps::Middleware,
          ConvenientService::Plugins::Service::HasJSendResultParamsValidations::UsingActiveModelValidations::Middleware
      end
    end
  end
end

Dry

module DryService
  module Config
    include ConvenientService::Concern

    included do
      include ConvenientService::Standard::Config

      concerns do
        use ConvenientService::Plugins::Common::AssignsAttributesInConstructor::UsingDryInitializer::Concern
        use ConvenientService::Plugins::Service::HasJSendResultParamsValidations::UsingDryValidation::Concern
      end

      middlewares :result do
        insert_before \
          ConvenientService::Plugins::Service::CanHaveConnectedSteps::Middleware,
          ConvenientService::Plugins::Service::HasJSendResultParamsValidations::UsingDryValidation::Middleware
      end
    end
  end
end

Custom

module CustomService
  module Config
    include ConvenientService::Concern

    included do
      include ConvenientService::Standard::Config

      if Rails.env.development? || Rails.env.test?
        include ConvenientService::AwesomePrintInspect::Config
      end

      concerns do
        use ConvenientService::Plugins::Common::AssignsAttributesInConstructor::UsingDryInitializer::Concern
        use ConvenientService::Plugins::Service::HasJSendResultParamsValidations::UsingActiveModelValidations::Concern
      end

      middlewares :result do
        insert_before \
          ConvenientService::Plugins::Service::CanHaveConnectedSteps::Middleware,
          ConvenientService::Plugins::Service::HasJSendResultParamsValidations::UsingActiveModelValidations::Middleware
      end

      if !Rails.env.test?
        middlewares :result do
          use ConvenientService::Plugins::Service::RescuesResultUnhandledExceptions::Middleware
        end

        middlewares :result, scope: :class do
          use ConvenientService::Plugins::Service::RescuesResultUnhandledExceptions::Middleware
        end
      end
    end
  end
end

Standard

class AssertFileExists
  include ApplicationService::Config

  attr_reader :path

  def initialize(path:)
    @path = path
  end

  def result
    return error("Path is `nil`") if path.nil?
    return error("Path is empty") if path.empty?

    return failure("File does not exist at path `#{path}`") unless ::File.exist?(path)

    success
  end
end

Rails

class AssertFileExists
  include RailsService::Config

  attribute :path, :string

  validates :path, presence: true

  def result
    return failure("File does not exist at path `#{path}`") unless ::File.exist?(path)

    success
  end
end

Dry

class AssertFileExists
  include DryService::Config

  option :path

  contract do
    schema do
      required(:path).value(:string)
    end
  end

  def result
    return failure("File does not exist at path `#{path}`") unless ::File.exist?(path)

    success
  end
end

Custom

class AssertFileExists
  include CustomService::Config

  option :path

  validates :path, presence: true

  def result
    return failure("File does not exist at path `#{path}`") unless ::File.exist?(path)

    success
  end
end

result = AssertFileExists.result(path: "Gemfile")

Standard

class AssertFileNotEmpty
  include ApplicationService::Config

  attr_accessor :path

  def initialize(path:)
    @path = path
  end

  def result
    return error("Path is `nil`") if path.nil?
    return error("Path is empty") if path.empty?

    return failure("File is empty at path `#{path}`") if ::File.zero?(path)

    success
  end
end

Rails

class AssertFileNotEmpty
  include RailsService::Config

  attribute :path, :string

  validates :path, presence: true

  def result
    return failure("File is empty at path `#{path}`") if ::File.zero?(path)

    success
  end
end

Dry

class AssertFileNotEmpty
  include DryService::Config

  option :path

  contract do
    schema do
      required(:path).value(:string)
    end
  end

  def result
    return failure("File is empty at path `#{path}`") if ::File.zero?(path)

    success
  end
end

Custom

class AssertFileNotEmpty
  include CustomService::Config

  option :path

  validates :path, presence: true

  def result
    return failure("File is empty at path `#{path}`") if ::File.zero?(path)

    success
  end
end

result = AssertFileNotEmpty.result(path: "Gemfile")

Standard

class ReadFileContent
  include ApplicationService::Config

  attr_reader :path

  step :validate_path
  step AssertFileExists, in: :path
  step AssertFileNotEmpty, in: :path
  step :result, in: :path, out: :content

  def initialize(path:)
    @path = path
  end

  def result
    success(content: ::File.read(path))
  end

  private

  def validate_path
    return error("Path is `nil`") if path.nil?
    return error("Path is empty") if path.empty?

    success
  end
end

Rails

class ReadFileContent
  include RailsService::Config

  attribute :path, :string

  validates :path, presence: true

  step AssertFileExists, in: :path
  step AssertFileNotEmpty, in: :path
  step :result, in: :path, out: :content

  def result
    success(content: ::File.read(path))
  end
end

Dry

class ReadFileContent
  include DryService::Config

  option :path

  contract do
    schema do
      required(:path).value(:string)
    end
  end

  step AssertFileExists, in: :path
  step AssertFileNotEmpty, in: :path
  step :result, in: :path, out: :content

  def result
    success(content: ::File.read(path))
  end
end

Custom

class ReadFileContent
  include CustomService::Config

  option :path

  validates :path, presence: true

  step AssertFileExists, in: :path
  step AssertFileNotEmpty, in: :path
  step :result, in: :path, out: :content

  def result
    success(content: ::File.read(path))
  end
end

result = ReadFileContent.result(path: "Gemfile")

More examples

Source Code	RSpec Specs
lib/convenient_service/examples	spec/lib/convenient_service