[api][webui] Catch backend errors when storing download repositories

This implements exception handling for storing download repository data in
the backend. This is needed to avoid inconsistency between frontend DB and
backend.

src/api/app/controllers/webui/download_on_demand_controller.rb

@@ -4,34 +4,51 @@ class Webui::DownloadOnDemandController < Webui::WebuiController
   def create
     @download_on_demand = DownloadRepository.new(permitted_params)
     authorize @download_on_demand
-    if @download_on_demand.save
-      @project.store
-      redirect_to project_repositories_path(@project), notice: "Successfully created Download on Demand"
-    else
-      redirect_to :back, error: "Download on Demand can't be created: #{@download_on_demand.errors.full_messages.to_sentence}"
+
+    begin
+      ActiveRecord::Base.transaction do
+        @download_on_demand.save!
+        @project.store
+      end
+    rescue ActiveRecord::RecordInvalid, ActiveXML::Transport::Error => exception
+      redirect_to :back, error: "Download on Demand can't be created: #{exception.message}"
+      return
     end
+
+    redirect_to project_repositories_path(@project), notice: "Successfully created Download on Demand"
   end
 
   def update
     @download_on_demand = DownloadRepository.find(params[:id])
     authorize @download_on_demand
-    if @download_on_demand.update_attributes(permitted_params)
-      @project.store
-      redirect_to project_repositories_path(@project), notice: "Successfully updated Download on Demand"
-    else
-      redirect_to :back, error: "Download on Demand can't be updated: #{@download_on_demand.errors.full_messages.to_sentence}"
+
+    begin
+      ActiveRecord::Base.transaction do
+        @download_on_demand.update_attributes!(permitted_params)
+        @project.store
+      end
+    rescue ActiveRecord::RecordInvalid, ActiveXML::Transport::Error => exception
+      redirect_to :back, error: "Download on Demand can't be updated: #{exception.message}"
+      return
     end
+
+    redirect_to project_repositories_path(@project), notice: "Successfully updated Download on Demand"
   end
 
   def destroy
     @download_on_demand = DownloadRepository.find(params[:id])
     authorize @download_on_demand
-    if @download_on_demand.destroy
-      @project.store
-      redirect_to project_repositories_path(@project), notice: "Successfully removed Download on Demand"
-    else
-      redirect_to :back, error: "Download on Demand can't be removed: #{@download_on_demand.errors.full_messages.to_sentence}"
+
+    begin
+      ActiveRecord::Base.transaction do
+        @download_on_demand.destroy!
+        @project.store
+      end
+    rescue ActiveRecord::RecordInvalid, ActiveXML::Transport::Error => exception
+      redirect_to :back, error: "Download on Demand can't be removed: #{exception.message}"
     end
+
+    redirect_to project_repositories_path(@project), notice: "Successfully removed Download on Demand"
   end
 
   private

src/api/app/models/download_repository.rb

@@ -11,4 +11,5 @@ class DownloadRepository < ActiveRecord::Base
   validates :repotype, inclusion: { in: REPOTYPES }
 
   delegate :to_s, to: :id
+
 end

src/api/spec/controllers/webui/download_on_demand_controller_spec.rb

@@ -69,7 +69,7 @@
       end
 
       it { is_expected.to redirect_to(root_path) }
-      it { expect(flash[:error]).to eq("Download on Demand can't be created: Arch can't be blank and Arch is not included in the list") }
+      it { expect(flash[:error]).to eq("Download on Demand can't be created: Validation failed: Arch can't be blank, Arch is not included in the list") }
       it { expect(assigns(:download_on_demand)).to be_kind_of(DownloadRepository) }
       it { expect(DownloadRepository.where(dod_parameters[:download_repository])).not_to exist }
     end