# module Net::HTTPHeader

The `HTTPHeader` module defines methods for reading and writing `HTTP` headers.

It is used as a mixin by other classes, to provide hash-like access to `HTTP` header values. Unlike raw hash access, `HTTPHeader` provides access via case-insensitive keys. It also provides methods for accessing commonly-used `HTTP` header values in more convenient formats.

### Public Instance Methods

[](key) click to toggle source

Returns the header field corresponding to the case-insensitive key. For example, a key of “Content-Type” might return “text/html”

    # File lib/net/http/header.rb, line 38
    def [](key)
      a = @header[key.downcase.to_s] or return nil
      a.join(', ')
    end

[]=(key, val) click to toggle source

Sets the header field corresponding to the case-insensitive key.

    # File lib/net/http/header.rb, line 44
    def []=(key, val)
      unless val
        @header.delete key.downcase.to_s
        return val
      end
      set_field(key, val)
    end

add_field(key, val) click to toggle source

Ruby 1.8.3

  Adds a value to a named header field, instead of replacing its value. Second argument `val` must be a `String`. See also `[]=`, `[]` and `get_fields`.

      request.add_field 'X-My-Header', 'a'
      p request['X-My-Header']              #=> "a"
      p request.get_fields('X-My-Header')   #=> ["a"]
      request.add_field 'X-My-Header', 'b'
      p request['X-My-Header']              #=> "a, b"
      p request.get_fields('X-My-Header')   #=> ["a", "b"]
      request.add_field 'X-My-Header', 'c'
      p request['X-My-Header']              #=> "a, b, c"
      p request.get_fields('X-My-Header')   #=> ["a", "b", "c"]

    # File lib/net/http/header.rb, line 67
    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

basic_auth(account, password) click to toggle source

`Set` the Authorization: header for “Basic” authorization.

    # File lib/net/http/header.rb, line 468
    def basic_auth(account, password)
      @header['authorization'] = [basic_encode(account, password)]
    end

canonical_each()
Alias for: each_capitalized
chunked?() click to toggle source

Returns “true” if the “transfer-encoding” header is present and set to “chunked”. This is an HTTP/1.1 feature, allowing the the content to be sent in “chunks” without at the outset stating the entire content length.

    # File lib/net/http/header.rb, line 329
    def chunked?
      return false unless @header['transfer-encoding']
      field = self['Transfer-Encoding']
      (/(?:\A|[^\-\w])chunked(?![\-\w])/i =~ field) ? true : false
    end

connection_close?() click to toggle source

    # File lib/net/http/header.rb, line 482
    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

connection_keep_alive?() click to toggle source

    # File lib/net/http/header.rb, line 489
    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

content_length() click to toggle source

Returns an `Integer` object which represents the `HTTP` Content-Length: header field, or `nil` if that field was not provided.

    # File lib/net/http/header.rb, line 310
    def content_length
      return nil unless key?('Content-Length')
      len = self['Content-Length'].slice(/\d+/) or
          raise Net::HTTPHeaderSyntaxError, 'wrong Content-Length format'
      len.to_i
    end

content_length=(len) click to toggle source

    # File lib/net/http/header.rb, line 317
    def content_length=(len)
      unless len
        @header.delete 'content-length'
        return nil
      end
      @header['content-length'] = [len.to_i.to_s]
    end

content_range() click to toggle source

Returns a `Range` object which represents the value of the Content-Range: header field. For a partial entity body, this indicates where this fragment fits inside the full entity body, as range of byte offsets.

    # File lib/net/http/header.rb, line 339
    def content_range
      return nil unless @header['content-range']
      m = %r<bytes\s+(\d+)-(\d+)/(\d+|\*)>i.match(self['Content-Range']) or
          raise Net::HTTPHeaderSyntaxError, 'wrong Content-Range format'
      m[1].to_i .. m[2].to_i
    end

content_type() click to toggle source

Returns a content type string such as “text/html”. This method returns nil if Content-Type: header field does not exist.

    # File lib/net/http/header.rb, line 354
    def content_type
      return nil unless main_type()
      if sub_type()
      then "#{main_type()}/#{sub_type()}"
      else main_type()
      end
    end

content_type=(type, params = {})
Alias for: set_content_type
delete(key) click to toggle source

Removes a header field, specified by case-insensitive key.

    # File lib/net/http/header.rb, line 186
    def delete(key)
      @header.delete(key.downcase.to_s)
    end

each()
Alias for: each_header
each_capitalized() { |capitalize(k), join(', ')| ... } click to toggle source

As for `each_header`, except the keys are provided in capitalized form.

Note that header names are capitalized systematically; capitalization may not match that used by the remote `HTTP` server in its response.

Returns an enumerator if no block is given.

    # File lib/net/http/header.rb, line 211
    def each_capitalized
      block_given? or return enum_for(__method__) { @header.size }
      @header.each do |k,v|
        yield capitalize(k), v.join(', ')
      end
    end

Also aliased as: canonical_each
each_capitalized_name() { |key| ... } click to toggle source

Iterates through the header names in the header, passing capitalized header names to the code block.

Note that header names are capitalized systematically; capitalization may not match that used by the remote `HTTP` server in its response.

Returns an enumerator if no block is given.

    # File lib/net/http/header.rb, line 167
    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

each_header() { |key| ... } click to toggle source

Iterates through the header names and values, passing in the name and value to the code block supplied.

Returns an enumerator if no block is given.

Example:

    response.header.each_header {|key,value| puts "#{key} = #{value}" }

    # File lib/net/http/header.rb, line 139
    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

Also aliased as: each
each_key()
Alias for: each_name
each_name() { |key| ... } click to toggle source

Iterates through the header names in the header, passing each header name to the code block.

Returns an enumerator if no block is given.

    # File lib/net/http/header.rb, line 152
    def each_name(&block)   #:yield: +key+
      block_given? or return enum_for(__method__) { @header.size }
      @header.each_key(&block)
    end

Also aliased as: each_key
each_value() { |value| ... } click to toggle source

Iterates through header values, passing each value to the code block.

Returns an enumerator if no block is given.

    # File lib/net/http/header.rb, line 178
    def each_value   #:yield: +value+
      block_given? or return enum_for(__method__) { @header.size }
      @header.each_value do |va|
        yield va.join(', ')
      end
    end

fetch(key, *args) { |key| ... } click to toggle source

Returns the header field corresponding to the case-insensitive key. Returns the default value `args`, or the result of the block, or raises an `IndexError` if there's no header field named `key` See `Hash#fetch`

    # File lib/net/http/header.rb, line 125
    def fetch(key, *args, &block)   #:yield: +key+
      a = @header.fetch(key.downcase.to_s, *args, &block)
      a.kind_of?(Array) ? a.join(', ') : a
    end

form_data=(params, sep = '&')
Alias for: set_form_data
get_fields(key) click to toggle source

Ruby 1.8.3

  Returns an array of header field strings corresponding to the case-insensitive `key`. This method allows you to get duplicated header fields without any processing. See also `[]`.

      p response.get_fields('Set-Cookie')
        #=> ["session=al98axx; expires=Fri, 31-Dec-1999 23:58:23",
             "query=rubyscript; expires=Fri, 31-Dec-1999 23:58:23"]
      p response['Set-Cookie']
        #=> "session=al98axx; expires=Fri, 31-Dec-1999 23:58:23, query=rubyscript; expires=Fri, 31-Dec-1999 23:58:23"

    # File lib/net/http/header.rb, line 115
    def get_fields(key)
      stringified_downcased_key = key.downcase.to_s
      return nil unless @header[stringified_downcased_key]
      @header[stringified_downcased_key].dup
    end

initialize_http_header(initheader) click to toggle source

    # File lib/net/http/header.rb, line 13
    def initialize_http_header(initheader)
      @header = {}
      return unless initheader
      initheader.each do |key, value|
        warn "net/http: duplicated HTTP header: #{key}", uplevel: 1 if key?(key) and $VERBOSE
        if value.nil?
          warn "net/http: nil HTTP header: #{key}", uplevel: 1 if $VERBOSE
        else
          value = value.strip # raise error for invalid byte sequences
          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

key?(key) click to toggle source

true if `key` header exists.

    # File lib/net/http/header.rb, line 191
    def key?(key)
      @header.key?(key.downcase.to_s)
    end

main_type() click to toggle source

Returns a content type string such as “text”. This method returns nil if Content-Type: header field does not exist.

    # File lib/net/http/header.rb, line 364
    def main_type
      return nil unless @header['content-type']
      self['Content-Type'].split(';').first.to_s.split('/')[0].to_s.strip
    end

proxy_basic_auth(account, password) click to toggle source

`Set` Proxy-Authorization: header for “Basic” authorization.

    # File lib/net/http/header.rb, line 473
    def proxy_basic_auth(account, password)
      @header['proxy-authorization'] = [basic_encode(account, password)]
    end

range() click to toggle source

Returns an `Array` of `Range` objects which represent the Range: `HTTP` header field, or `nil` if there is no such header.

    # File lib/net/http/header.rb, line 227
    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 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 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 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 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 Net::HTTPHeaderSyntaxError, 'only one suffix-byte-range-spec with zero suffix-length'
      end
      result
    end

range=(r, e = nil)
Alias for: set_range
range_length() click to toggle source

The length of the range represented in Content-Range: header.

    # File lib/net/http/header.rb, line 347
    def range_length
      r = content_range() or return nil
      r.end - r.begin + 1
    end

set_content_type(type, params = {}) click to toggle source

Sets the content type in an `HTTP` header. The `type` should be a full `HTTP` content type, e.g. “text/html”. The `params` are an optional `Hash` of parameters to add after the content type, e.g. {'charset' => 'iso-8859-1'}

    # File lib/net/http/header.rb, line 397
    def set_content_type(type, params = {})
      @header['content-type'] = [type + params.map{|k,v|"; #{k}=#{v}"}.join('')]
    end

Also aliased as: content_type=
set_form(params, enctype='application/x-www-form-urlencoded', formopt={}) click to toggle source

`Set` an HTML form data set. `params` is the form data set; it is an `Array` of Arrays or a `Hash` +enctype is the type to encode the form data set. It is application/x-www-form-urlencoded or multipart/form-data. `formopt` is an optional hash to specify the detail.

boundary

  the boundary of the multipart message

charset

  the charset of the message. All names and the values of non-file fields are encoded as the charset.

Each item of params is an array and contains following items:

`name`

  the name of the field

`value`

  the value of the field, it should be a `String` or a `File`

`opt`

  an optional hash to specify additional information

Each item is a file field or a normal field. If `value` is a `File` object or the `opt` have a filename key, the item is treated as a file field.

If Transfer-Encoding is set as chunked, this send the request in chunked encoding. Because chunked encoding is HTTP/1.1 feature, you must confirm the server to support HTTP/1.1 before sending it.

Example:

    http.set_form([["q", "ruby"], ["lang", "en"]])

See also RFC 2388, RFC 2616, HTML 4.01, and HTML5

    # File lib/net/http/header.rb, line 453
    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

set_form_data(params, sep = '&') click to toggle source

`Set` header fields and a body from HTML form data. `params` should be an `Array` of Arrays or a `Hash` containing HTML form data. Optional argument `sep` means data record separator.

Values are URL encoded as necessary and the content-type is set to application/x-www-form-urlencoded

Example:

    http.form_data = {"q" => "ruby", "lang" => "en"}
    http.form_data = {"q" => ["ruby", "perl"], "lang" => "en"}
    http.set_form_data({"q" => "ruby", "lang" => "en"}, ';')

    # File lib/net/http/header.rb, line 416
    def set_form_data(params, sep = '&')
      query = URI.encode_www_form(params)
      query.gsub!(/&/, sep) if sep != '&'
      self.body = query
      self.content_type = 'application/x-www-form-urlencoded'
    end

Also aliased as: form_data=
set_range(r, e = nil) click to toggle source

Sets the `HTTP` Range: header. Accepts either a `Range` object as a single argument, or a beginning index and a length from that index. Example:

    req.range = (0..1023)
    req.set_range 0, 1023

    # File lib/net/http/header.rb, line 277
    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 Net::HTTPHeaderSyntaxError, 'range.first is negative' if first < 0
          raise Net::HTTPHeaderSyntaxError, 'range.last is negative' if last < 0
          raise 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

Also aliased as: range=
sub_type() click to toggle source

Returns a content type string such as “html”. This method returns nil if Content-Type: header field does not exist or sub-type is not given (e.g. “Content-Type: text”).

    # File lib/net/http/header.rb, line 372
    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

to_hash() click to toggle source

Returns a `Hash` consisting of header names and array of values. e.g. {“cache-control” => [“private”],

    "content-type" => ["text/html"],
    "date" => ["Wed, 22 Jun 2005 22:11:50 GMT"]}

    # File lib/net/http/header.rb, line 200
    def to_hash
      @header.dup
    end

type_params() click to toggle source

Any parameters specified for the content type, returned as a `Hash`. For example, a header of Content-Type: text/html; charset=EUC-JP would result in `type_params` returning {'charset' => 'EUC-JP'}

    # File lib/net/http/header.rb, line 382
    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

### Private Instance Methods

append_field_value(ary, val) click to toggle source

    # File lib/net/http/header.rb, line 91
            def append_field_value(ary, val)
      case val
      when Enumerable
        val.each{|x| append_field_value(ary, x)}
      else
        val = val.to_s
        if /[\r\n]/n.match?(val.b)
          raise ArgumentError, 'header field value cannot include CR/LF'
        end
        ary.push val
      end
    end

basic_encode(account, password) click to toggle source

    # File lib/net/http/header.rb, line 477
    def basic_encode(account, password)
      'Basic ' + ["#{account}:#{password}"].pack('m0')
    end

capitalize(name) click to toggle source

    # File lib/net/http/header.rb, line 220
    def capitalize(name)
      name.to_s.split(/-/).map {|s| s.capitalize }.join('-')
    end

set_field(key, val) click to toggle source

    # File lib/net/http/header.rb, line 76
            def set_field(key, val)
      case val
      when Enumerable
        ary = []
        append_field_value(ary, val)
        @header[key.downcase.to_s] = ary
      else
        val = val.to_s # for compatibility use to_s instead of to_str
        if val.b.count("\r\n") > 0
          raise ArgumentError, 'header field value cannot include CR/LF'
        end
        @header[key.downcase.to_s] = [val]
      end
    end