824e9a13cb
* Add service generator * Finalize service generator * Add documentation * Explicitly require rails/generators * Update Zeitwerk initializer * Remove explicit require * Update docs/backend/service-objects.md Co-authored-by: Ridhwana <Ridhwana.Khan16@gmail.com> Co-authored-by: Ridhwana <Ridhwana.Khan16@gmail.com>
114 lines
2 KiB
Markdown
114 lines
2 KiB
Markdown
---
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title: Service Objects
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---
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## What are Service Objects
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Service objects are Plain Old Ruby Objects (POROs) which encapsulate a whole
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business process/user interaction.
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Our services are located in `app/services` with the corresponding specs in
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`spec/services`. Their main interface is a class level method named `call`, as
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in the following example:
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```ruby
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class ImportUsers
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def self.call(arg1)
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new(arg1).call
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end
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def initialize(arg1)
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@arg1 = arg1
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end
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def call
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# import code goes here
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end
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end
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```
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To distinguish services from models we often give them verb names vs noun
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names, e.g. `ImportUsers` instead of `UserImporter`.
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## Generating Service Objects
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To make our services more consistent we use a custom Rails generator. Some usage
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examples:
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**Generate a non-namespaced service without arguments**
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`$ rails generate service DoTheThing`
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```ruby
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# app/services/do_the_thing.rb
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class DoTheThing
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def self.call
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new.call
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end
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def call
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end
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end
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```
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```ruby
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# spec/services/do_the_thing_spec.rb
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require "rails_helper"
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RSpec.describe DoTheThing, type: :service do
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pending "add some examples to (or delete) #{__FILE__}"
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end
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```
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**Generate a non-namespaced service with arguments:**
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`$ rails generate service DoTheThing arg1 arg2`
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```ruby
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# app/services/do_the_thing.rb
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class DoTheThing
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def self.call(arg1, arg2)
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new(arg1, arg2).call
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end
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def initialize(arg1, arg2)
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@arg1 = arg1
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@arg2 = arg2
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end
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def call
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end
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end
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```
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The generated spec is the same as above.
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**Generate a namespaced service with arguments**
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`$ rails generate service things/dothem arg1 arg2`
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```ruby
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# app/services/things/do_them.rb
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class Things::DoThem
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def self.call(arg1, arg2)
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new(arg1, arg2).call
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end
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def initialize(arg1, arg2)
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@arg1 = arg1
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@arg2 = arg2
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end
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def call
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end
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end
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```
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```ruby
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# spec/services/things/do_them_spec.rb
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require "rails_helper"
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RSpec.describe Things::DoThem, type: :service do
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pending "add some examples to (or delete) #{__FILE__}"
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end
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```
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