don't try to register crossref dois in handle system

Gemfile.lock

@@ -109,14 +109,14 @@ GEM
       latex-decode (~> 0.0)
     binding_of_caller (0.8.0)
       debug_inspector (>= 0.0.1)
-    bolognese (1.4.3)
+    bolognese (1.4.5)
       activesupport (>= 4.2.5, < 6)
       benchmark_methods (~> 0.7)
       bibtex-ruby (~> 4.1)
       builder (~> 3.2, >= 3.2.2)
       citeproc-ruby (~> 1.1, >= 1.1.10)
       colorize (~> 0.8.1)
-      concurrent-ruby (~> 1.0.5)
+      concurrent-ruby (~> 1.1, >= 1.1.5)
       csl-styles (~> 1.0, >= 1.0.1.8)
       edtf (~> 3.0, >= 3.0.4)
       faraday (= 0.17.0)
@@ -158,7 +158,7 @@ GEM
     colorize (0.8.1)
     commonmarker (0.17.13)
       ruby-enum (~> 0.5)
-    concurrent-ruby (1.0.5)
+    concurrent-ruby (1.1.5)
     countries (2.1.4)
       i18n_data (~> 0.8.0)
       money (~> 6.9)
@@ -371,7 +371,7 @@ GEM
     pwqgen.rb (0.1.0)
       docopt (~> 0.5)
       sysrandom
-    rack (2.1.2)
+    rack (2.2.1)
     rack-accept (0.4.5)
       rack (>= 0.4)
     rack-cors (1.1.1)

app/models/concerns/crosscitable.rb

@@ -86,7 +86,7 @@ def update_xml
       end.to_h.compact
 
       meta = from.present? ? send("read_" + from, { string: xml, doi: doi, sandbox: sandbox }.merge(read_attrs)) : {}
-      
+
       xml = datacite_xml
 
       write_attribute(:xml, xml)
@@ -125,19 +125,19 @@ def clean_xml(string)
 
     def well_formed_xml(string)
       return nil unless string.present?
-  
+
       from_xml(string) || from_json(string)
 
       string
     end
-  
+
     def from_xml(string)
       return nil unless string.start_with?('<?xml version=') || string.start_with?('<resource ')
 
       doc = Nokogiri::XML(string) { |config| config.strict.noblanks }
       doc.to_xml
     end
-  
+
     def from_json(string)
       linter = JsonLint::Linter.new
       errors_array = []
@@ -156,7 +156,7 @@ def get_content_type(string)
 
       begin
         JSON.parse(string)
-        return "json"
+        "json"
       rescue
         "string"
       end

app/models/doi.rb

@@ -1235,19 +1235,19 @@ def validatable?
   end
 
   # update URL in handle system for registered and findable state
-  # providers europ and ethz do their own handle registration, so fetch url from handle system instead
+  # providers europ, and DOI registration agencies do their own handle registration, so fetch url from handle system instead
   def update_url
     return nil if current_user.nil? || !is_registered_or_findable?
 
-    if %w(europ).include?(provider_id)
+    if %w(ethz europ crossref medra kisti jalc op).include?(provider_id)
       UrlJob.perform_later(doi)
     else
       HandleJob.perform_later(doi)
     end
   end
 
   def update_media
-    return nil unless content_url.present?
+    return nil if content_url.blank?
 
     media.delete_all