Extract public body CSV export to its own class

- SRP: Do one thing. PublicBodyCSV converts a
  collection of bodies in to a CSV formatted
  String
- Adds some parenthesis around parameters in
  PublicBodyController#list_all_csv
- Let the controller handle what records to pull
  out for the CSV export

Arguably this doesn't really need to be anything
to do with PublicBody, but it allows us to set
nice defaults.

1 files changed, 95 insertions, 0 deletions

diff --git a/lib/public_body_csv.rb b/lib/public_body_csv.rb
new file mode 100644
index 000000000..afb5d9043
--- /dev/null
+++ b/lib/public_body_csv.rb
@@ -0,0 +1,95 @@
+require 'csv'
+
+# Public: Generate a CSV representation of PublicBody instances
+#
+# Examples
+#
+#   bodies = PublicBody.search('useless')
+#
+#   csv = PublicBodyCSV.new(:fields => [:name, :calculated_home_page],
+#                           :headers => ['Name', 'Home Page'])
+#
+#   bodies.each { |body| csv << body }
+#
+#   csv.generate
+#   # => Name,Home Page
+#        Department for Humpadinking,http://localhost
+#        Ministry of Silly Walks,http://www.localhost
+#        Department of Loneliness,http://localhost
+class PublicBodyCSV
+
+    def self.default_fields
+        [:name,
+         :short_name,
+         :url_name,
+         :tag_string,
+         :calculated_home_page,
+         :publication_scheme,
+         :disclosure_log,
+         :notes,
+         :created_at,
+         :updated_at,
+         :version]
+    end
+
+    # TODO: Generate headers from fields
+    def self.default_headers
+        ['Name',
+         'Short name',
+         'URL name',
+         'Tags',
+         'Home page',
+         'Publication scheme',
+         'Disclosure log',
+         'Notes',
+         'Created at',
+         'Updated at',
+         'Version']
+    end
+
+    attr_reader :fields, :headers, :rows
+
+    def initialize(args = {})
+        @fields = args.fetch(:fields, self.class.default_fields)
+        @headers = args.fetch(:headers, self.class.default_headers)
+        @rows = []
+    end
+
+    def <<(public_body)
+        # Allow join_rows to handle newlines because of differences between
+        # CSV.generate_line in 1.8 / 1.9+
+        if RUBY_VERSION.to_f >= 1.9
+            rows << CSV.generate_line(collect_public_body_attributes(public_body), :row_sep => '')
+        else
+            rows << CSV.generate_line(collect_public_body_attributes(public_body))
+        end
+    end
+
+    # TODO: Just use CSV.generate when Ruby 1.8.7 support is dropped
+    def generate
+        csv = generate_header_row
+        csv << join_rows
+        csv << "\n"
+    end
+
+    private
+
+    def join_rows
+        rows.join("\n")
+    end
+
+    def generate_header_row
+        # Add a newline because of differences between
+        # CSV.generate_line in 1.8 / 1.9+
+        row = CSV.generate_line(headers)
+        row += "\n" unless RUBY_VERSION.to_f >= 1.9
+        row
+    end
+
+    def collect_public_body_attributes(public_body)
+        fields.map do |field|
+            public_body.respond_to?(field) ? public_body.send(field) : ''
+        end
+    end
+
+end