allow empty features on ArcGIS server

app/models/data_import.rb

@@ -827,6 +827,7 @@ class DataImport < Sequel::Model
       synchronization = CartoDB::Synchronization::Member.new(id: synchronization_id).fetch
       synchronization.name    = self.table_name
       synchronization.log_id  = log.id
+      byebug
       
       if importer.success?
         imported_table = ::Table.get_by_table_id(self.table_id)

services/importer/lib/importer/datasource_downloader.rb

@@ -127,8 +127,7 @@ module CartoDB
           return if resource_data.size.zero?
           data = resource_data
         else
-          return if resource_data.empty?
-          data = StringIO.new(resource_data)
+          data = resource_data.empty? ? StringIO.new : StringIO.new(resource_data)
         end
         name = filename
 

services/importer/lib/importer/json2csv.rb

@@ -13,6 +13,7 @@ module CartoDB
       end
 
       def run
+        byebug
         data = parse(filepath)
         return self if complex?(data)
         File.open(converted_filepath, 'w') { |file| file.write csv_from(data) }
@@ -54,7 +55,8 @@ module CartoDB
       def parse(filepath)
         return {} unless File.exists?(filepath)
         file  = File.open(filepath)
-        data  = ::JSON.parse(file.read.force_encoding('UTF-8'))
+        raw_content = file.read.force_encoding('UTF-8')
+        data  = raw_content.empty? ? {} : ::JSON.parse(raw_content)
         file.close
         data
       end

services/importer/lib/importer/runner.rb

@@ -156,7 +156,7 @@ module CartoDB
       def import(source_file, downloader, loader_object = nil)
         loader = loader_object || loader_for(source_file).new(@job, source_file)
 
-        raise EmptyFileError if source_file.empty?
+        raise EmptyFileError if source_file.empty? && !can_be_empty(downloader.datasource)
 
         loader.set_importer_stats(@importer_stats) if loader.respond_to?(:set_importer_stats)
         loader.options = @loader_options.merge(tracker: tracker, importer_config: @importer_config)
@@ -256,11 +256,9 @@ module CartoDB
           end
 
           @importer_stats.timing('unpack') do
-            if @downloader.source_file.present?
-              log.append "Unpacking #{@downloader.source_file.fullpath}"
-              tracker.call('unpacking')
-              unpacker.run(@downloader.source_file.fullpath)
-            end
+            log.append "Unpacking #{@downloader.source_file.fullpath}"
+            tracker.call('unpacking')
+            unpacker.run(@downloader.source_file.fullpath)
           end
 
           @importer_stats.timing('import') do
@@ -445,6 +443,10 @@ module CartoDB
       def delete_job_table
         @job.delete_job_table
       end
+
+      def can_be_empty(datasource)
+        return datasource.present? && datasource.is_a?(Datasources::Url::ArcGIS)
+      end
     end
   end
 end