Problem:
- Want to have JS Promise-like way of handling logic execution, with ability to chain handlers, plus useful additions like guard adn rollback?
Solution:
- Use wrap execution class within Handle.it block and chain handlers in the Promise manner
Notes:
- Could be good matching in rails controllers, when it is important to have declarative way of handling execution.
- Use guard feature with 'it' method args, like:
def valid?
false
end
Handle.it(when: valid?, not_valid_error: 'User not found')
.with { |r| redirect_to wellcome(user), notice: 'Welcome!' }
.on_fail { |e| pp e.message }
=> 'User not found'if valid returns 'false', it goes to on_fail block with specific error message
- Use rollback feature with 'with' method args, like:
Handle.it { "Ruby rules" }
.with(on_fail: :rollback) { |res| res.upcase.split.unknow_method_call }
.result
=> 'Ruby rules'if you want to have last successful result neglecting errors.
gem install handleitgem 'handleit', require: %w[handle]class UsersController < ApplicationController
def auth
Handle.it(when: valid?, not_valid_error: 'User not found') do
AuthService.authenticate!
end
.with { |res| redirect_to wellcome(user), notice: 'Welcome!'}
.on_fail { |e| redirect_to login(user), notice: "Authentication error: #{e.message}" }
end
def valid?
# some validation logic
end
end
# ...
class Service
class << self
def some_cool_logic
"some_cool_string"
end
def error_raiser
raise StandardError
end
end
end
# ...
# Handle.it with
pry(main)> Handle.it { Service.some_cool_logic }
pry(main)> .with { |res| res + " bla" }
pry(main)> .with { |res| pp res }
pry(main)> .on_fail { |e| pp e }
pry(main)> .result
=> "some_cool_string bla"
# Handle.it shortcut methods
pry(main)> H.it { Service.some_cool_logic }
pry(main)> .> { |res| res + " bla" }
pry(main)> .> { |res| pp res }
pry(main)> .e { |e| pp e }
pry(main)> .<=
=> "some_cool_string bla"
# Handle.it on_fail
pry(main)> Handle.it { Service.error_raiser }
pry(main)> .with { |res| res + " bla" }
pry(main)> .with { |res| pp res }
pry(main)> .on_fail { |e| pp e }
=> #<StandardError: StandardError>
# pipelining result
pry(main)> Handle.it { "Elixir rocks" }
pry(main)> .with { |res| res.size - 1 }
pry(main)> .with { |res| res.upcase.split.first }
pry(main)> .result
=> 5
# rollback result instead of sending it into on_fail block, so it returns latest successful
pry(main)> Handle.it { "Elixir rocks" }
pry(main)> .with { |res| res.size - 1 }
pry(main)> .with(on_fail: :rollback) { |res| res.upcase.split.unknow_method_call }
pry(main)> .on_fail { |e| pp e }
pry(main)> .result
=> 11