Adding rake tasks time:zones:all, time:zones:us and time:zones:local for finding time zone names for config.time_zone option

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@9074 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

1 files changed, 43 insertions, 0 deletions

diff --git a/railties/lib/tasks/misc.rake b/railties/lib/tasks/misc.rake
index e44ab2cf17..fcd860ae16 100644
--- a/railties/lib/tasks/misc.rake
+++ b/railties/lib/tasks/misc.rake
@@ -8,3 +8,46 @@ desc 'Generate a crytographically secure secret key. This is typically used to g
 task :secret do
   puts Rails::SecretKeyGenerator.new(ENV['ID']).generate_secret
 end
+
+namespace :time do
+  namespace :zones do
+    desc 'Displays names of all time zones recognized by the Rails TimeZone class, grouped by offset. Results can be filtered with optional OFFSET parameter, e.g., OFFSET=-6'
+    task :all => :environment do
+      build_time_zone_list(:all)
+    end
+    
+    desc 'Displays names of US time zones recognized by the Rails TimeZone class, grouped by offset. Results can be filtered with optional OFFSET parameter, e.g., OFFSET=-6'
+    task :us => :environment do
+      build_time_zone_list(:us_zones)
+    end
+    
+    desc 'Displays names of time zones recognized by the Rails TimeZone class with the same offset as the system local time'
+    task :local => :environment do
+      build_time_zone_list(:all, Time.now.beginning_of_year.utc_offset)
+    end
+    
+    # to find UTC -06:00 zones, OFFSET can be set to either -6, -6:00 or 21600
+    def build_time_zone_list(method, offset = ENV['OFFSET'])
+      if offset
+        offset = if offset.to_s.match(/(\+|-)?(\d+):(\d+)/)
+          sign = $1 == '-' ? -1 : 1
+          hours, minutes = $2.to_f, $3.to_f
+          ((hours * 3600) + (minutes.to_f * 60)) * sign
+        elsif offset.to_f.abs <= 13
+          offset.to_f * 3600
+        else
+          offset.to_f
+        end
+      end
+      previous_offset = nil
+      TimeZone.__send__(method).each do |zone|
+        if offset.nil? || offset == zone.utc_offset
+          puts "\n* UTC #{zone.formatted_offset} *" unless zone.utc_offset == previous_offset
+          puts zone.name
+          previous_offset = zone.utc_offset
+        end
+      end
+      puts "\n"
+    end
+  end
+end
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