Class: Dropcaster::Channel

Inherits:
Object
  • Object
show all
Includes:
ERB::Util
Defined in:
lib/dropcaster/channel.rb

Overview

Represents a podcast feed in the RSS 2.0 format

Constant Summary collapse

STORAGE_UNITS = 
%w(Byte KB MB GB TB)
MAX_KEYWORD_COUNT = 
12

Instance Method Summary collapse

Constructor Details

#initialize(sources, attributes) ⇒ Channel

Instantiate a new Channel object. sources must be present and can be a String or Array of Strings, pointing to a one or more directories or MP3 files.

attributes is a hash with all attributes for the channel. The following attributes are mandatory when a new channel is created:

  • :title - Title (name) of the podcast

  • :url - URL to the podcast

  • :description - Short description of the podcast (a few words)



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# File 'lib/dropcaster/channel.rb', line 24

def initialize(sources, attributes)
  # Assert mandatory attributes
  [:title, :url, :description].each{|attr|
    raise MissingAttributeError.new(attr) if attributes[attr].blank?
  }

  @attributes = attributes
  @attributes[:explicit] = yes_no_or_input(attributes[:explicit])
  @source_files = Array.new

  # if (sources.respond_to?(:each)) # array
  if sources.is_a? Array
    sources.each do |src|
      add_files(src)
    end
  else
    # single file or directory
    add_files(sources)
  end

  # If not absolute, prepend the image URL with the channel's base to make an absolute URL
  unless @attributes[:image_url].blank? || @attributes[:image_url] =~ /^https?:/
    Dropcaster.logger.info("Channel image URL '#{@attributes[:image_url]}' is relative, so we prepend it with the channel URL '#{@attributes[:url]}'")
    @attributes[:image_url] = (URI.parse(@attributes[:url]) + @attributes[:image_url]).to_s
  end

  # If enclosures_url is not given, take the channel URL as a base.
  if @attributes[:enclosures_url].blank?
    Dropcaster.logger.info("No enclosure URL given, using the channel's enclosure URL")
    @attributes[:enclosures_url] = @attributes[:url]
  end

  # Warn if keyword count is larger than recommended
  assert_keyword_count(@attributes[:keywords])

  channel_template = @attributes[:channel_template] || File.join(File.dirname(__FILE__), '..', '..', 'templates', 'channel.rss.erb')

  begin
    @erb_template = ERB.new(IO.read(channel_template), 0, "%<>")
  rescue Errno::ENOENT => e
    raise TemplateNotFoundError.new(e.message)
  end
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(meth, *args) ⇒ Object

delegate all unknown methods to @attributes



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# File 'lib/dropcaster/channel.rb', line 143

def method_missing(meth, *args)
  m = meth.id2name
  if /=$/ =~ m
    @attributes[m.chop.to_sym] = (args.length < 2 ? args[0] : args)
  else
    @attributes[m.to_sym]
  end
end

Instance Method Details

#humanize_size(number) ⇒ Object

Fixed version of gist.github.com/260184



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# File 'lib/dropcaster/channel.rb', line 122

def humanize_size(number)
  return nil if number.nil?

  storage_units_format = '%n %u'

  if number.to_i < 1024
    unit = number > 1 ? 'Bytes' : 'Byte'
    return storage_units_format.gsub(/%n/, number.to_i.to_s).gsub(/%u/, unit)
  else
    max_exp  = STORAGE_UNITS.size - 1
    number   = Float(number)
    exponent = (Math.log(number) / Math.log(1024)).to_i # Convert to base 1024
    exponent = max_exp if exponent > max_exp # we need this to avoid overflow for the highest unit
    number  /= 1024 ** exponent

    unit = STORAGE_UNITS[exponent]
    return storage_units_format.gsub(/%n/, number.to_i.to_s).gsub(/%u/, unit)
  end
end

#humanize_time(secs) ⇒ Object

from stackoverflow.com/questions/4136248



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# File 'lib/dropcaster/channel.rb', line 112

def humanize_time(secs)
  [[60, :s], [60, :m], [24, :h], [1000, :d]].map{ |count, name|
    if secs > 0
      secs, n = secs.divmod(count)
      "#{n.to_i}#{name}"
    end
  }.compact.reverse.join(' ')
end

#items ⇒ Object

Returns all items (episodes) of this channel, ordered by newest-first.



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# File 'lib/dropcaster/channel.rb', line 80

def items
  all_items = Array.new
  @source_files.each{|src|

    item = Item.new(src)

    Dropcaster.logger.debug("Adding new item from file #{src}")

    # set author and image_url from channel if empty
    if item.artist.blank?
      Dropcaster.logger.info("#{src} has no artist, using the channel's author")
      item.tag.artist = @attributes[:author]
    end

    if item.image_url.blank?
      Dropcaster.logger.info("#{src} has no image URL set, using the channel's image URL")
      item.image_url = @attributes[:image_url]
    end

    # construct absolute URL, based on the channel's enclosures_url attribute
    item.url = (URI.parse(enclosures_url) + URI.encode(item.file_name))

    # Warn if keyword count is larger than recommended
    assert_keyword_count(item.keywords)

    all_items << item
  }

  all_items.sort{|x, y| y.pub_date <=> x.pub_date}
end

#to_rss ⇒ Object

Returns this channel as an RSS representation. The actual rendering is done with the help of an ERB template. By default, it is expected as ../../templates/channel.rss.erb (relative) to channel.rb.



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# File 'lib/dropcaster/channel.rb', line 73

def to_rss
  @erb_template.result(binding)
end