Merge pull request #6445 from CartoDB/6403-improve_empty_csv_handling

Improve empty CSV files handling

lib/cartodb/import_error_codes.rb

@@ -40,8 +40,8 @@ module CartoDB
       source: ERROR_SOURCE_USER
     },
     1005 => {
-      title: 'Zero byte file',
-      what_about: "The file appears to have no information. Double check using a local tool such as QGIS that the file is indeed correct. If everything appears fine, try uploading it again or <a href='mailto:support@cartodb.com?subject=Zero byte file'>contact us</a>.",
+      title: 'Empty file',
+      what_about: "The file appears to have no processable information. Double check that the file is indeed correct and it contains supported data. If everything appears fine, try uploading it again or <a href='mailto:support@cartodb.com?subject=Empty file'>contact us</a>.",
       source: ERROR_SOURCE_USER
     },
     1006 => {

services/importer/lib/importer/csv_normalizer.rb

@@ -169,7 +169,9 @@ module CartoDB
       end
 
       def single_column?
-        ::CSV.parse(first_line, csv_options).first.length < 2
+        columns = ::CSV.parse(first_line, csv_options)
+        raise EmptyFileError.new if !columns.any?
+        columns.first.length < 2
       end
 
       def multiple_column(row)
@@ -208,8 +210,9 @@ module CartoDB
       def first_line
         return @first_line if @first_line
         stream.rewind
-        @first_line ||= stream.gets
+        @first_line ||= stream.gets || ''
         stream.rewind
+        @first_line
       end
 
       def release

services/importer/spec/unit/csv_normalizer_spec.rb

@@ -9,7 +9,7 @@ include CartoDB::Importer2::Doubles
 describe CartoDB::Importer2::CsvNormalizer do
 
   BUG_COLUMNS_WRONG_SPLIT_FIXTURE_FILE = "#{File.dirname(__FILE__)}/bug_columns_wrong_split.csv"
-  
+
   describe '#run' do
     it 'transforms the file using a proper comma delimiter' do
       fixture = tab_delimiter_factory
@@ -21,6 +21,16 @@ describe CartoDB::Importer2::CsvNormalizer do
       csv.run
       csv.delimiter.should eq ','
     end
+    it 'raise if detects an empty file' do
+      fixture = empty_file_factory
+
+      csv     = CartoDB::Importer2::CsvNormalizer.new(fixture, Log.new)
+      expect {
+        csv.run
+      }.to raise_exception CartoDB::Importer2::EmptyFileError
+
+      FileUtils.rm(fixture)
+    end
   end
 
   describe '#detect_delimiter' do
@@ -215,6 +225,14 @@ describe CartoDB::Importer2::CsvNormalizer do
     filepath
   end
 
+  def empty_file_factory
+    filepath = get_temp_csv_fullpath
+
+    FileUtils.touch(filepath)
+
+    filepath
+  end
+
   def quoted_string_with_delimiter_factory
     filepath = get_temp_csv_fullpath