Class: Wasserstand::Provider::PegelOnline

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Includes:
Enumerable
Defined in:
lib/wasserstand/provider/pegel_online.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(url = 'http://www.pegelonline.wsv.de/svgz/pegelstaende_neu.xml') ⇒ PegelOnline

Returns a new instance of PegelOnline.



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# File 'lib/wasserstand/provider/pegel_online.rb', line 10

def initialize(url = 'http://www.pegelonline.wsv.de/svgz/pegelstaende_neu.xml')
  @url = url
  @names = []
end

Instance Attribute Details

#cache ⇒ Object 



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# File 'lib/wasserstand/provider/pegel_online.rb', line 36

def cache
  @cache ||= HeapCache.new
end

Instance Method Details

#levels ⇒ Object 



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# File 'lib/wasserstand/provider/pegel_online.rb', line 32

def levels
  waterways.inject([]){|result, ww| result.concat(ww.levels.values)}
end

#waterways ⇒ Object

Cache entries may expire, and simply iterating over the list of current cache entries would render an incomplete picture. Therefore we maintain the knowledge of what waterways exist in a single list, which is the authoritative source of what waterways exist.



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# File 'lib/wasserstand/provider/pegel_online.rb', line 16

def waterways
  replenish if @names.empty?
  @names.map do |name|
    ww = cache.get(name) # no fetch with block in Dalli, so we cannot use it here either ...

    # Not finding the Waterway for a name means it was removed from the cache, but it may or may not exist in the backend. Therefore we need to replenish our cache including our knowledge about the name.
    if ww.nil?
      replenish
      ww = cache.get(name)
      # Still nil? Does not matter. Replenish has auto-removed an outdated name.
    end

    ww
  end.compact # don't return nil entries
end