Add SWOB-ML Observation download function

README.markdown

@@ -89,7 +89,7 @@ After the base entities have been created in the OGC SensorThings API service, t
 $ transload get observations --source environment_canada --station XCM --cache /datastore/weather
 ```
 
-In this example, observations for the Environment Canada station `XCM` (Cambridge Bay) are downloaded to a local cache in the `/datastore/weather/environment_canada/XCM/YYYY/MM/DD/HHMMSS.xml` file. The year/month/day and hour/minute/second are parsed from the observation file provided by the data source.
+In this example, observations for the Environment Canada station `XCM` (Cambridge Bay) are downloaded to a local cache in the `/datastore/weather/environment_canada/XCM/YYYY/MM/DD/HHMMSS+0000.xml` file. The year/month/day and hour/minute/second/time zone offset are parsed from the observation file provided by the data source.
 
 If a file already exists with the same name, it is **overwritten**.
 

lib/transloader/environment_canada_station.rb

@@ -1,3 +1,5 @@
+require 'date'
+require 'fileutils'
 require 'json'
 require 'nokogiri'
 
@@ -19,6 +21,7 @@ def initialize(id, provider, properties)
       @properties = properties
       @metadata = {}
       @metadata_path = "#{@provider.cache_path}/#{EnvironmentCanadaProvider::CACHE_DIRECTORY}/metadata/#{@id}.json"
+      @observations_path = "#{@provider.cache_path}/#{EnvironmentCanadaProvider::CACHE_DIRECTORY}/#{@id}"
     end
 
     # Parse metadata from the Provider properties and the SWOB-ML file for a
@@ -202,5 +205,21 @@ def put_metadata(server_url)
     def save_metadata
       IO.write(@metadata_path, JSON.pretty_generate(@metadata))
     end
+
+    # Save the SWOB-ML file to file cache
+    def save_observations
+      xml = observation_xml
+
+      # Parse date from SWOB-ML
+      timestamp = DateTime.parse(xml.xpath('//po:identification-elements/po:element[@name="date_tm"]/@value', NAMESPACES).text)
+
+      # Create cache directory structure
+      date_path = timestamp.strftime('%Y/%m/%d')
+      time_path = timestamp.strftime('%H%M%S%z.xml')
+      FileUtils.mkdir_p("#{@observations_path}/#{date_path}")
+
+      # Dump XML to file
+      IO.write("#{@observations_path}/#{date_path}/#{time_path}", xml.to_s)
+    end
   end
 end

transload

@@ -14,6 +14,17 @@ def get_station_metadata(source, station_id, cache)
   end
 end
 
+def get_station_observations(source, station_id, cache)
+  case source
+  when "environment_canada"
+    provider = Transloader::EnvironmentCanadaProvider.new(cache)
+    station = provider.get_station(station_id)
+    station.save_observations
+  else
+    puts "Support for source not implemented"
+  end
+end
+
 def put_station_metadata(source, station_id, cache, destination)
   case source
   when "environment_canada"
@@ -37,7 +48,7 @@ when :get
   when :metadata
     get_station_metadata(args.source, args.station, args.cache)
   when :observations
-    puts "Not yet implemented"
+    get_station_observations(args.source, args.station, args.cache)
   end
 when :put
   case args.object