extracted cell formatting into module

which also enables adding new formats simply by defining a new module

lib/open_project/xls_export/formatters.rb

@@ -0,0 +1,78 @@
+module OpenProject::XlsExport
+  module Formatters
+    def self.all
+      self.constants.map do |const|
+        Kernel.const_get("OpenProject::XlsExport::Formatters::#{const}")
+      end.select do |const|
+        const.is_a?(Class) && const != DefaultFormatter
+      end + [DefaultFormatter]
+    end
+
+    ##
+    # Returns a Hash mapping columns to formatters to be used.
+    def self.for_columns(columns)
+      formatters = self.all
+      entries = columns.map do |column|
+        [column, formatters.find { |formatter| formatter.apply? column }.new]
+      end
+      Hash[entries]
+    end
+
+    class DefaultFormatter
+      ##
+      # Takes a QueryColumn and returns true if this formatter should be used to handle it.
+      def self.apply?(column)
+        true
+      end
+
+      ##
+      # Takes a WorkPackage and a QueryColumn and returns the value to be exported.
+      def format(work_package, column)
+        column.value work_package
+      end
+
+      ##
+      # Takes a QueryColumn and returns format options for it.
+      def format_options(column)
+        {}
+      end
+    end
+
+    class TimeFormatter < DefaultFormatter
+      def self.apply?(column)
+        h = column.caption
+        h =~ /.*hours.*/ || h == "spent_time"
+      end
+
+      def format_options(column)
+        {:number_format => "0.0 h"}
+      end
+    end
+
+    class CostFormatter
+      include Redmine::I18n
+      include ActionView::Helpers::NumberHelper
+
+      def self.apply?(column)
+        column.name.to_s =~ /.*cost.*/
+      end
+
+      def format(work_package, column)
+        column.real_value work_package
+      end
+
+      def format_options(column)
+        {:number_format => excel_format_string}
+      end
+
+      def excel_format_string
+        # [$CUR] makes sure we have an actually working currency format with arbitrary currencies
+        curr = "[$CUR]".gsub "CUR", ERB::Util.h(Setting.plugin_openproject_costs['costs_currency'])
+        format = ERB::Util.h Setting.plugin_openproject_costs['costs_currency_format']
+        number = '#,##0.00'
+
+        format.gsub("%n", number).gsub("%u", curr)
+      end
+    end
+  end
+end

lib/open_project/xls_export/patches/work_packages_controller_patch.rb

@@ -37,27 +37,24 @@ module OpenProject::XlsExport
           columns = query.columns
 
           sb = SpreadsheetBuilder.new("#{I18n.t(:label_work_package_plural)}")
+          formatters = OpenProject::XlsExport::Formatters.for_columns(columns)
 
           headers = columns.collect(&:caption).unshift("#")
           headers << WorkPackage.human_attribute_name(:description) if options[:show_descriptions]
           sb.add_headers headers, 0
 
-          issues.each do |issue|
+          issues.each do |work_package|
             row = (columns.collect do |column|
-                    cv = column.value(issue)
+                    cv = formatters[column].format work_package, column
                     (cv.respond_to? :name) ? cv.name : cv
-                  end).unshift(issue.id)
-            row << issue.description if options[:show_descriptions]
+                  end).unshift(work_package.id)
+            row << work_package.description if options[:show_descriptions]
             sb.add_row(row)
           end
 
-          headers.each_with_index do |h,idx|
-            h = h.to_s.downcase
-            if (h =~ /.*hours.*/ or h == "spent_time")
-              sb.add_format_option_to_column idx, :number_format => "0.0 h"
-            elsif (h =~ /.*cost.*/)
-              sb.add_format_option_to_column idx, :number_format => number_to_currency(0.00)
-            end
+          columns.each_with_index do |column, i|
+            options = formatters[column].format_options column
+            sb.add_format_option_to_column i + 1, options
           end
 
           sb