✨ create Users::FindByUsername operation

app/controllers/users_controller.rb

@@ -4,8 +4,8 @@ class UsersController < ApplicationController
   skip_before_action :authenticate_user!, only: %i[show]
 
   def show
-    user = UserProfile.find_by(username: params[:username]).user
+    result = Users::FindByUsername.result(username: params[:username])
 
-    render Users::ShowPage.new(user: user)
+    render Users::ShowPage.new(user: result.user)
   end
 end

app/operations/users/find_by_username.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module Users
+  class FindByUsername < Actor
+    input :username, type: String
+
+    output :user, type: User
+
+    def call
+      profile = UserProfile.find_by(username: username)
+
+      fail!(error: :not_found) if profile.blank?
+
+      self.user = profile.user
+    end
+  end
+end

spec/operations/users/find_by_username_spec.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe Users::FindByUsername, type: :operation do
+  context "when user with given username exists" do
+    it "is a success" do
+      user = create(:user)
+      create(:user_profile, username: "johndoe", user: user)
+
+      result = described_class.result(username: "johndoe")
+
+      expect(result.success?).to be true
+    end
+
+    it "returns found user for given username" do
+      user = create(:user)
+      create(:user_profile, username: "johndoe", user: user)
+
+      result = described_class.result(username: "johndoe")
+
+      expect(result.user).to eq(user)
+    end
+  end
+
+  context "when user with given username doesn't exist" do
+    it "is a failure" do
+      result = described_class.result(username: "not-found-username")
+
+      expect(result.failure?).to be true
+    end
+
+    it "returns not found error" do
+      result = described_class.result(username: "not-found-username")
+
+      expect(result.error).to be :not_found
+    end
+  end
+end