diff --git a/app/controllers/dois_controller.rb b/app/controllers/dois_controller.rb
index b21b9ceb7..17479971b 100644
--- a/app/controllers/dois_controller.rb
+++ b/app/controllers/dois_controller.rb
@@ -7,40 +7,39 @@ class DoisController < ApplicationController
   include Crosscitable
   include MetricsHelper # mixes in your helper method as class method
 
-
   prepend_before_action :authenticate_user!
   before_action :set_include, only: [:index, :show, :create, :update]
   before_action :set_raven_context, only: [:create, :update, :validate]
 
   def index
     sort = case params[:sort]
-          when "name" then { "doi" => { order: 'asc' }}
-          when "-name" then { "doi" => { order: 'desc' }}
-          when "created" then { created: { order: 'asc' }}
-          when "-created" then { created: { order: 'desc' }}
-          when "updated" then { updated: { order: 'asc' }}
-          when "-updated" then { updated: { order: 'desc' }}
-          when "published" then { published: { order: 'asc' }}
-          when "-published" then { published: { order: 'desc' }}
-          when "view-count" then { view_count: { order: 'asc' }}
-          when "-view-count" then { view_count: { order: 'desc' }}
-          when "download-count" then { download_count: { order: 'asc' }}
-          when "-download-count" then { download_count: { order: 'desc' }}
-          when "citation-count" then { citation_count: { order: 'asc' }}
-          when "-citation-count" then { citation_count: { order: 'desc' }}
-          when "relevance" then { "_score": { "order": "desc" }}
-          else { updated: { order: 'desc' }}
-          end
+           when "name" then { "doi" => { order: 'asc' }}
+           when "-name" then { "doi" => { order: 'desc' }}
+           when "created" then { created: { order: 'asc' }}
+           when "-created" then { created: { order: 'desc' }}
+           when "updated" then { updated: { order: 'asc' }}
+           when "-updated" then { updated: { order: 'desc' }}
+           when "published" then { published: { order: 'asc' }}
+           when "-published" then { published: { order: 'desc' }}
+           when "view-count" then { view_count: { order: 'asc' }}
+           when "-view-count" then { view_count: { order: 'desc' }}
+           when "download-count" then { download_count: { order: 'asc' }}
+           when "-download-count" then { download_count: { order: 'desc' }}
+           when "citation-count" then { citation_count: { order: 'asc' }}
+           when "-citation-count" then { citation_count: { order: 'desc' }}
+           when "relevance" then { "_score": { "order": "desc" }}
+           else { updated: { order: 'desc' }}
+           end
 
     page = page_from_params(params)
 
     sample_group_field = case params[:sample_group]
-      when "client" then "client_id"
-      when "data-center" then "client_id"
-      when "provider" then "provider_id"
-      when "resource-type" then "types.resourceTypeGeneral"
-      else nil
-    end
+                         when "client" then "client_id"
+                         when "data-center" then "client_id"
+                         when "provider" then "provider_id"
+                         when "resource-type" then "types.resourceTypeGeneral"
+                         else nil
+                         end
 
     response = nil
 
@@ -419,7 +418,7 @@ def update
       options[:params] = {
         current_ability: current_ability,
         detail: true,
-        affiliation: params[:affiliation]
+        affiliation: params[:affiliation],
       }
 
       render json: DoiSerializer.new(@doi, options).serialized_json, status: exists ? :ok : :created
@@ -431,7 +430,7 @@ def update
 
   def undo
     @doi = Doi.where(doi: safe_params[:doi]).first
-    fail ActiveRecord::RecordNotFound unless @doi.present?
+    fail ActiveRecord::RecordNotFound if @doi.blank?
 
     authorize! :undo, @doi
 
@@ -482,13 +481,13 @@ def random
 
   def get_url
     @doi = Doi.where(doi: params[:id]).first
-    fail ActiveRecord::RecordNotFound unless @doi.present?
+    fail ActiveRecord::RecordNotFound if @doi.blank?
     
     authorize! :get_url, @doi
 
     if !@doi.is_registered_or_findable? || %w(europ crossref medra jalc kisti op).include?(@doi.provider_id) || %w(Crossref mEDRA).include?(@doi.agency)
       url = @doi.url
-      head :no_content and return unless url.present?
+      head :no_content && return if url.blank?
     else
       response = @doi.get_url
 
@@ -512,12 +511,12 @@ def get_url
   def get_dois
     authorize! :get_urls, Doi
 
-    client = Client.where('datacentre.symbol = ?', current_user.uid.upcase).first
+    client = Client.where("datacentre.symbol = ?", current_user.uid.upcase).first
     client_prefix = client.prefixes.first
-    head :no_content and return unless client_prefix.present?
+    head :no_content && return if client_prefix.blank?
 
     dois = Doi.get_dois(prefix: client_prefix.prefix, username: current_user.uid.upcase, password: current_user.password)
-    if dois.length > 0
+    if dois.length.positive?
       render json: { dois: dois }.to_json, status: :ok
     else
       head :no_content
diff --git a/app/models/concerns/helpable.rb b/app/models/concerns/helpable.rb
index 1e36a8c54..4e8bd17d6 100644
--- a/app/models/concerns/helpable.rb
+++ b/app/models/concerns/helpable.rb
@@ -61,6 +61,8 @@ def register_url
         self.__elasticsearch__.index_document
       elsif response.status == 404
         Rails.logger.info "[Handle] Error updating URL for DOI " + doi + ": not found"
+      elsif response.status == 408
+        Rails.logger.warn "[Handle] Error updating URL for DOI " + doi + ": timeout"
       else
         Rails.logger.error "[Handle] Error updating URL for DOI " + doi + ": " + response.body.inspect unless Rails.env.test?
       end
@@ -135,10 +137,10 @@ def https_to_http(url)
 
   module ClassMethods
     def get_dois(options={})
-      return OpenStruct.new(body: { "errors" => [{ "title" => "Prefix missing" }] }) unless options[:prefix].present?
+      return OpenStruct.new(body: { "errors" => [{ "title" => "Prefix missing" }] }) if options[:prefix].blank?
 
-      count_url = ENV['HANDLE_URL'] + "/api/handles?prefix=#{options[:prefix]}&pageSize=0"
-      response = Maremma.get(count_url, username: "300%3A#{ENV['HANDLE_USERNAME']}", password: ENV['HANDLE_PASSWORD'], ssl_self_signed: true, timeout: 60)
+      count_url = ENV["HANDLE_URL"] + "/api/handles?prefix=#{options[:prefix]}&pageSize=0"
+      response = Maremma.get(count_url, username: "300%3A#{ENV['HANDLE_USERNAME']}", password: ENV["HANDLE_PASSWORD"], ssl_self_signed: true, timeout: 60)
 
       total = response.body.dig("data", "totalCount").to_i
       dois = []
@@ -146,10 +148,10 @@ def get_dois(options={})
       if total > 0
         # walk through paginated results
         total_pages = (total.to_f / 1000).ceil
-        
+
         (0...total_pages).each do |page|
-          url = ENV['HANDLE_URL'] + "/api/handles?prefix=#{options[:prefix]}&page=#{page}&pageSize=1000"
-          response = Maremma.get(url, username: "300%3A#{ENV['HANDLE_USERNAME']}", password: ENV['HANDLE_PASSWORD'], ssl_self_signed: true, timeout: 60)
+          url = ENV["HANDLE_URL"] + "/api/handles?prefix=#{options[:prefix]}&page=#{page}&pageSize=1000"
+          response = Maremma.get(url, username: "300%3A#{ENV['HANDLE_USERNAME']}", password: ENV["HANDLE_PASSWORD"], ssl_self_signed: true, timeout: 60)
           if response.status == 200
             dois += (response.body.dig("data", "handles") || [])
           else
@@ -167,16 +169,16 @@ def get_dois(options={})
     end
 
     def get_doi(options={})
-      return OpenStruct.new(body: { "errors" => [{ "title" => "DOI missing" }] }) unless options[:doi].present?
+      return OpenStruct.new(body: { "errors" => [{ "title" => "DOI missing" }] }) if options[:doi].blank?
 
       url = Rails.env.production? ? "https://doi.org" : "https://handle.test.datacite.org"
       url += "/api/handles/#{options[:doi]}"
-      response = Maremma.get(url, username: "300%3A#{ENV['HANDLE_USERNAME']}", password: ENV['HANDLE_PASSWORD'], ssl_self_signed: true, timeout: 10)
+      response = Maremma.get(url, username: "300%3A#{ENV['HANDLE_USERNAME']}", password: ENV["HANDLE_PASSWORD"], ssl_self_signed: true, timeout: 10)
 
       if response.status == 200
         response
       elsif response.status == 404
-        {}
+        OpenStruct.new(status: 404, body: { "errors" => [{ "status" => 404, "title" => "Not found." }] })
       else
         text = "Error " + response.body["errors"].inspect
 
@@ -186,7 +188,7 @@ def get_doi(options={})
     end
 
     def delete_doi(options={})
-      return OpenStruct.new(body: { "errors" => [{ "title" => "DOI missing" }] }) unless options[:doi].present?
+      return OpenStruct.new(body: { "errors" => [{ "title" => "DOI missing" }] }) if options[:doi].blank?
       return OpenStruct.new(body: { "errors" => [{ "title" => "Only DOIs with prefix 10.5072 can be deleted" }] }) unless options[:doi].start_with?("10.5072")
 
       url = "#{ENV['HANDLE_URL']}/api/handles/#{options[:doi]}"
@@ -195,7 +197,7 @@ def delete_doi(options={})
       if response.status == 200
         response
       elsif response.status == 404
-        {}
+        OpenStruct.new(status: 404, body: { "errors" => [{ "status" => 404, "title" => "Not found." }] })
       else
         text = "Error " + response.body["errors"].inspect
 
@@ -214,9 +216,7 @@ def parse_attributes(element, options={})
         element.fetch( CGI.unescapeHTML(content), nil)
       elsif element.is_a?(Array)
         a = element.map { |e| e.is_a?(Hash) ? e.fetch( CGI.unescapeHTML(content), nil) : e }.uniq
-        a = options[:first] ? a.first : a.unwrap
-      else
-        nil
+        options[:first] ? a.first : a.unwrap
       end
     end
   end