opensmtpd_rails_frontend/app/controllers/domains_controller.rb

class DomainsController < ApplicationController
  before_action :set_domain, only: %i[ show edit update destroy ]

  # GET /domains or /domains.json
  def index
    @domains = Domain.all
  end

  # GET /domains/1 or /domains/1.json
  def show
  end

  # GET /domains/new
  def new
    @domain = Domain.new
  end

  # GET /domains/1/edit
  def edit
  end

  # POST /domains or /domains.json
  def create
    @domain = Domain.new(domain_params)

    respond_to do |format|
      if @domain.save
        format.html { redirect_to domain_url(@domain), notice: "Domain was successfully created." }
        format.json { render :show, status: :created, location: @domain }
      else
        format.html { render :new, status: :unprocessable_entity }
        format.json { render json: @domain.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /domains/1 or /domains/1.json
  def update
    pre_domain_name = @domain.domain
    respond_to do |format|
      if @domain.update(domain_params)
        # now we need to update the credentials and virtuals

        @domain.credentials.each do |credential|
          credential.email.sub! pre_domain_name, @domain.domain
          credential.save
        end

        @domain.virtuals.each do |virtual|
          virtual.email.sub! pre_domain_name, @domain.domain
          virtual.save
        end

        format.html { redirect_to domain_url(@domain), notice: "Domain was successfully updated." }
        format.json { render :show, status: :ok, location: @domain }
      else
        format.html { render :edit, status: :unprocessable_entity }
        format.json { render json: @domain.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /domains/1 or /domains/1.json
  def destroy
    @domain.destroy

    respond_to do |format|
      format.html { redirect_to domains_url, notice: "Domain was successfully destroyed." }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_domain
      @domain = Domain.find(params[:id])
    end

    # Only allow a list of trusted parameters through.
    def domain_params
      params.require(:domain).permit(:domain)
    end
end