module Gem::Net::HTTPHeader

def [](key)
  a = @header[key.downcase.to_s] or return nil
  a.join(', ')
end

def []=(key, val)
  unless val
    @header.delete key.downcase.to_s
    return val
  end
  set_field(key, val)
end

def add_field(key, val)
  stringified_downcased_key = key.downcase.to_s
  if @header.key?(stringified_downcased_key)
    append_field_value(@header[stringified_downcased_key], val)
  else
    set_field(key, val)
  end
end

def append_field_value(ary, val)
al
numerable
each{|x| append_field_value(ary, x)}
= val.to_s
[\r\n]/n.match?(val.b)
ise ArgumentError, 'header field value cannot include CR/LF'
push val

def basic_auth(account, password)
  @header['authorization'] = [basic_encode(account, password)]
end

def basic_encode(account, password)
  'Basic ' + ["#{account}:#{password}"].pack('m0')
end

def capitalize(name)
  name.to_s.split('-'.freeze).map {|s| s.capitalize }.join('-'.freeze)
end

def chunked?
  return false unless @header['transfer-encoding']
  field = self['Transfer-Encoding']
  (/(?:\A|[^\-\w])chunked(?![\-\w])/i =~ field) ? true : false
end

def connection_close?
  token = /(?:\A|,)\s*close\s*(?:\z|,)/i
  @header['connection']&.grep(token) {return true}
  @header['proxy-connection']&.grep(token) {return true}
  false
end

def connection_keep_alive?
  token = /(?:\A|,)\s*keep-alive\s*(?:\z|,)/i
  @header['connection']&.grep(token) {return true}
  @header['proxy-connection']&.grep(token) {return true}
  false
end

def content_length
  return nil unless key?('Content-Length')
  len = self['Content-Length'].slice(/\d+/) or
      raise Gem::Net::HTTPHeaderSyntaxError, 'wrong Content-Length format'
  len.to_i
end

def content_length=(len)
  unless len
    @header.delete 'content-length'
    return nil
  end
  @header['content-length'] = [len.to_i.to_s]
end

def content_range
  return nil unless @header['content-range']
  m = %r<\A\s*(\w+)\s+(\d+)-(\d+)/(\d+|\*)>.match(self['Content-Range']) or
      raise Gem::Net::HTTPHeaderSyntaxError, 'wrong Content-Range format'
  return unless m[1] == 'bytes'
  m[2].to_i .. m[3].to_i
end

def content_type
  main = main_type()
  return nil unless main
  sub = sub_type()
  if sub
    "#{main}/#{sub}"
  else
    main
  end
end

def delete(key)
  @header.delete(key.downcase.to_s)
end

def each_capitalized
  block_given? or return enum_for(__method__) { @header.size }
  @header.each do |k,v|
    yield capitalize(k), v.join(', ')
  end
end

def each_capitalized_name  #:yield: +key+
  block_given? or return enum_for(__method__) { @header.size }
  @header.each_key do |k|
    yield capitalize(k)
  end
end

def each_header   #:yield: +key+, +value+
  block_given? or return enum_for(__method__) { @header.size }
  @header.each do |k,va|
    yield k, va.join(', ')
  end
end

def each_name(&block)   #:yield: +key+
  block_given? or return enum_for(__method__) { @header.size }
  @header.each_key(&block)
end

def each_value   #:yield: +value+
  block_given? or return enum_for(__method__) { @header.size }
  @header.each_value do |va|
    yield va.join(', ')
  end
end

def fetch(key, *args, &block)   #:yield: +key+
  a = @header.fetch(key.downcase.to_s, *args, &block)
  a.kind_of?(Array) ? a.join(', ') : a
end

def get_fields(key)
  stringified_downcased_key = key.downcase.to_s
  return nil unless @header[stringified_downcased_key]
  @header[stringified_downcased_key].dup
end

def initialize_http_header(initheader) #:nodoc:
  @header = {}
  return unless initheader
  initheader.each do |key, value|
    warn "net/http: duplicated HTTP header: #{key}", uplevel: 3 if key?(key) and $VERBOSE
    if value.nil?
      warn "net/http: nil HTTP header: #{key}", uplevel: 3 if $VERBOSE
    else
      value = value.strip # raise error for invalid byte sequences
      if key.to_s.bytesize > MAX_KEY_LENGTH
        raise ArgumentError, "too long (#{key.bytesize} bytes) header: #{key[0, 30].inspect}..."
      end
      if value.to_s.bytesize > MAX_FIELD_LENGTH
        raise ArgumentError, "header #{key} has too long field value: #{value.bytesize}"
      end
      if value.count("\r\n") > 0
        raise ArgumentError, "header #{key} has field value #{value.inspect}, this cannot include CR/LF"
      end
      @header[key.downcase.to_s] = [value]
    end
  end
end

def key?(key)
  @header.key?(key.downcase.to_s)
end

def main_type
  return nil unless @header['content-type']
  self['Content-Type'].split(';').first.to_s.split('/')[0].to_s.strip
end

def proxy_basic_auth(account, password)
  @header['proxy-authorization'] = [basic_encode(account, password)]
end

def range
  return nil unless @header['range']
  value = self['Range']
  # byte-range-set = *( "," OWS ) ( byte-range-spec / suffix-byte-range-spec )
  #   *( OWS "," [ OWS ( byte-range-spec / suffix-byte-range-spec ) ] )
  # corrected collected ABNF
  # http://tools.ietf.org/html/draft-ietf-httpbis-p5-range-19#section-5.4.1
  # http://tools.ietf.org/html/draft-ietf-httpbis-p5-range-19#appendix-C
  # http://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-19#section-3.2.5
  unless /\Abytes=((?:,[ \t]*)*(?:\d+-\d*|-\d+)(?:[ \t]*,(?:[ \t]*\d+-\d*|-\d+)?)*)\z/ =~ value
    raise Gem::Net::HTTPHeaderSyntaxError, "invalid syntax for byte-ranges-specifier: '#{value}'"
  end
  byte_range_set = $1
  result = byte_range_set.split(/,/).map {|spec|
    m = /(\d+)?\s*-\s*(\d+)?/i.match(spec) or
            raise Gem::Net::HTTPHeaderSyntaxError, "invalid byte-range-spec: '#{spec}'"
    d1 = m[1].to_i
    d2 = m[2].to_i
    if m[1] and m[2]
      if d1 > d2
        raise Gem::Net::HTTPHeaderSyntaxError, "last-byte-pos MUST greater than or equal to first-byte-pos but '#{spec}'"
      end
      d1..d2
    elsif m[1]
      d1..-1
    elsif m[2]
      -d2..-1
    else
      raise Gem::Net::HTTPHeaderSyntaxError, 'range is not specified'
    end
  }
  # if result.empty?
  # byte-range-set must include at least one byte-range-spec or suffix-byte-range-spec
  # but above regexp already denies it.
  if result.size == 1 && result[0].begin == 0 && result[0].end == -1
    raise Gem::Net::HTTPHeaderSyntaxError, 'only one suffix-byte-range-spec with zero suffix-length'
  end
  result
end

def range_length
  r = content_range() or return nil
  r.end - r.begin + 1
end

def set_content_type(type, params = {})
  @header['content-type'] = [type + params.map{|k,v|"; #{k}=#{v}"}.join('')]
end

def set_field(key, val)
al
numerable
= []
nd_field_value(ary, val)
der[key.downcase.to_s] = ary
= val.to_s # for compatibility use to_s instead of to_str
al.b.count("\r\n") > 0
ise ArgumentError, 'header field value cannot include CR/LF'
der[key.downcase.to_s] = [val]

def set_form(params, enctype='application/x-www-form-urlencoded', formopt={})
  @body_data = params
  @body = nil
  @body_stream = nil
  @form_option = formopt
  case enctype
  when /\Aapplication\/x-www-form-urlencoded\z/i,
    /\Amultipart\/form-data\z/i
    self.content_type = enctype
  else
    raise ArgumentError, "invalid enctype: #{enctype}"
  end
end

def set_form_data(params, sep = '&')
  query = Gem::URI.encode_www_form(params)
  query.gsub!(/&/, sep) if sep != '&'
  self.body = query
  self.content_type = 'application/x-www-form-urlencoded'
end

def set_range(r, e = nil)
  unless r
    @header.delete 'range'
    return r
  end
  r = (r...r+e) if e
  case r
  when Numeric
    n = r.to_i
    rangestr = (n > 0 ? "0-#{n-1}" : "-#{-n}")
  when Range
    first = r.first
    last = r.end
    last -= 1 if r.exclude_end?
    if last == -1
      rangestr = (first > 0 ? "#{first}-" : "-#{-first}")
    else
      raise Gem::Net::HTTPHeaderSyntaxError, 'range.first is negative' if first < 0
      raise Gem::Net::HTTPHeaderSyntaxError, 'range.last is negative' if last < 0
      raise Gem::Net::HTTPHeaderSyntaxError, 'must be .first < .last' if first > last
      rangestr = "#{first}-#{last}"
    end
  else
    raise TypeError, 'Range/Integer is required'
  end
  @header['range'] = ["bytes=#{rangestr}"]
  r
end

def size   #:nodoc: obsolete
  @header.size
end

def sub_type
  return nil unless @header['content-type']
  _, sub = *self['Content-Type'].split(';').first.to_s.split('/')
  return nil unless sub
  sub.strip
end

def to_hash
  @header.dup
end

def type_params
  result = {}
  list = self['Content-Type'].to_s.split(';')
  list.shift
  list.each do |param|
    k, v = *param.split('=', 2)
    result[k.strip] = v.strip
  end
  result
end