property_file_reader.rb

=begin
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A utility class that reads a properties file and returns a hash containing the
properties.

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=end

class PropertyFileReader
  # Read a properties file and return a hash.
  #
  # Parameters: the path to the properties file
  #
  # The hash includes the special property "properties_file_path", which holds
  # the path to the properties file.
  #
  def self.read(file_path)
    properties = {}
    properties["properties_file_path"] = File.expand_path(file_path)

    if File.exist?(file_path)
      File.open(file_path) do |file|
        file.each_line do |line|
          line.strip!
          if line.length == 0 || line[0] == ?# || line[0] == ?!
            # ignore blank lines, and lines starting with '#' or '!'.
          elsif line =~ /(.*?)\s*[=:]\s*(.*)/
            # key and value are separated by '=' or ':' and optional whitespace.
            properties[$1.strip] = $2
          else
            # No '=' or ':' means that the value is empty.
            properties[line] = ''
          end
        end
      end
    end

    return properties
  end
end