Module: Rack::Utils

Included in:
Chunked, Chunked::Body, ContentLength, ContentType
Defined in:
lib/rack/utils.rb

Overview

Rack::Utils contains a grab-bag of useful methods for writing web applications adopted from all kinds of Ruby libraries.

Defined Under Namespace

Classes: Context, HeaderHash

Constant Summary collapse

ParameterTypeError =
QueryParser::ParameterTypeError
InvalidParameterError =
QueryParser::InvalidParameterError
DEFAULT_SEP =
QueryParser::DEFAULT_SEP
COMMON_SEP =
QueryParser::COMMON_SEP
KeySpaceConstrainedParams =
QueryParser::Params
ESCAPE_HTML =
{
  "&" => "&",
  "<" => "&lt;",
  ">" => "&gt;",
  "'" => "&#x27;",
  '"' => "&quot;",
  "/" => "&#x2F;"
}
ESCAPE_HTML_PATTERN =
Regexp.union(*ESCAPE_HTML.keys)
HTTP_STATUS_CODES =

Every standard HTTP code mapped to the appropriate message. Generated with:

curl -s https://www.iana.org/assignments/http-status-codes/http-status-codes-1.csv | \
  ruby -ne 'm = /^(\d{3}),(?!Unassigned|\(Unused\))([^,]+)/.match($_) and \
            puts "#{m[1]} => \x27#{m[2].strip}\x27,"'
{
  100 => 'Continue',
  101 => 'Switching Protocols',
  102 => 'Processing',
  103 => 'Early Hints',
  200 => 'OK',
  201 => 'Created',
  202 => 'Accepted',
  203 => 'Non-Authoritative Information',
  204 => 'No Content',
  205 => 'Reset Content',
  206 => 'Partial Content',
  207 => 'Multi-Status',
  208 => 'Already Reported',
  226 => 'IM Used',
  300 => 'Multiple Choices',
  301 => 'Moved Permanently',
  302 => 'Found',
  303 => 'See Other',
  304 => 'Not Modified',
  305 => 'Use Proxy',
  307 => 'Temporary Redirect',
  308 => 'Permanent Redirect',
  400 => 'Bad Request',
  401 => 'Unauthorized',
  402 => 'Payment Required',
  403 => 'Forbidden',
  404 => 'Not Found',
  405 => 'Method Not Allowed',
  406 => 'Not Acceptable',
  407 => 'Proxy Authentication Required',
  408 => 'Request Timeout',
  409 => 'Conflict',
  410 => 'Gone',
  411 => 'Length Required',
  412 => 'Precondition Failed',
  413 => 'Payload Too Large',
  414 => 'URI Too Long',
  415 => 'Unsupported Media Type',
  416 => 'Range Not Satisfiable',
  417 => 'Expectation Failed',
  421 => 'Misdirected Request',
  422 => 'Unprocessable Entity',
  423 => 'Locked',
  424 => 'Failed Dependency',
  425 => 'Too Early',
  426 => 'Upgrade Required',
  428 => 'Precondition Required',
  429 => 'Too Many Requests',
  431 => 'Request Header Fields Too Large',
  451 => 'Unavailable for Legal Reasons',
  500 => 'Internal Server Error',
  501 => 'Not Implemented',
  502 => 'Bad Gateway',
  503 => 'Service Unavailable',
  504 => 'Gateway Timeout',
  505 => 'HTTP Version Not Supported',
  506 => 'Variant Also Negotiates',
  507 => 'Insufficient Storage',
  508 => 'Loop Detected',
  509 => 'Bandwidth Limit Exceeded',
  510 => 'Not Extended',
  511 => 'Network Authentication Required'
}
STATUS_WITH_NO_ENTITY_BODY =

Responses with HTTP status codes that should not have an entity body

Hash[((100..199).to_a << 204 << 304).product([true])]
SYMBOL_TO_STATUS_CODE =
Hash[*HTTP_STATUS_CODES.map { |code, message|
  [message.downcase.gsub(/\s|-|'/, '_').to_sym, code]
}.flatten]
PATH_SEPS =
Regexp.union(*[::File::SEPARATOR, ::File::ALT_SEPARATOR].compact)
NULL_BYTE =
"\0"

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.default_query_parserObject

Returns the value of attribute default_query_parser



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# File 'lib/rack/utils.rb', line 23

def default_query_parser
  @default_query_parser
end

.multipart_part_limitObject

Returns the value of attribute multipart_part_limit



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# File 'lib/rack/utils.rb', line 58

def multipart_part_limit
  @multipart_part_limit
end

Class Method Details



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# File 'lib/rack/utils.rb', line 220

def add_cookie_to_header(header, key, value)
  case value
  when Hash
    domain  = "; domain=#{value[:domain]}"   if value[:domain]
    path    = "; path=#{value[:path]}"       if value[:path]
    max_age = "; max-age=#{value[:max_age]}" if value[:max_age]
    expires = "; expires=#{value[:expires].httpdate}" if value[:expires]
    secure = "; secure"  if value[:secure]
    httponly = "; HttpOnly" if (value.key?(:httponly) ? value[:httponly] : value[:http_only])
    same_site =
      case value[:same_site]
      when false, nil
        nil
      when :lax, 'Lax', :Lax
        '; SameSite=Lax'
      when true, :strict, 'Strict', :Strict
        '; SameSite=Strict'
      else
        raise ArgumentError, "Invalid SameSite value: #{value[:same_site].inspect}"
      end
    value = value[:value]
  end
  value = [value] unless Array === value

  cookie = "#{escape(key)}=#{value.map { |v| escape v }.join('&')}#{domain}" \
    "#{path}#{max_age}#{expires}#{secure}#{httponly}#{same_site}"

  case header
  when nil, ''
    cookie
  when String
    [header, cookie].join("\n")
  when Array
    (header + [cookie]).join("\n")
  else
    raise ArgumentError, "Unrecognized cookie header value. Expected String, Array, or nil, got #{header.inspect}"
  end
end

Adds a cookie that will remove a cookie from the client. Hence the strange method name.



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# File 'lib/rack/utils.rb', line 298

def add_remove_cookie_to_header(header, key, value = {})
  new_header = make_delete_cookie_header(header, key, value)

  add_cookie_to_header(new_header, key,
             { value: '', path: nil, domain: nil,
               max_age: '0',
               expires: Time.at(0) }.merge(value))

end

.best_q_match(q_value_header, available_mimes) ⇒ Object



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# File 'lib/rack/utils.rb', line 145

def best_q_match(q_value_header, available_mimes)
  values = q_values(q_value_header)

  matches = values.map do |req_mime, quality|
    match = available_mimes.find { |am| Rack::Mime.match?(am, req_mime) }
    next unless match
    [match, quality]
  end.compact.sort_by do |match, quality|
    (match.split('/', 2).count('*') * -10) + quality
  end.last
  matches && matches.first
end

.build_nested_query(value, prefix = nil) ⇒ Object



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# File 'lib/rack/utils.rb', line 114

def build_nested_query(value, prefix = nil)
  case value
  when Array
    value.map { |v|
      build_nested_query(v, "#{prefix}[]")
    }.join("&")
  when Hash
    value.map { |k, v|
      build_nested_query(v, prefix ? "#{prefix}[#{escape(k)}]" : escape(k))
    }.reject(&:empty?).join('&')
  when nil
    prefix
  else
    raise ArgumentError, "value must be a Hash" if prefix.nil?
    "#{prefix}=#{escape(value)}"
  end
end

.build_query(params) ⇒ Object



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# File 'lib/rack/utils.rb', line 103

def build_query(params)
  params.map { |k, v|
    if v.class == Array
      build_query(v.map { |x| [k, x] })
    else
      v.nil? ? escape(k) : "#{escape(k)}=#{escape(v)}"
    end
  }.join("&")
end

.byte_ranges(env, size) ⇒ Object

Parses the “Range:” header, if present, into an array of Range objects. Returns nil if the header is missing or syntactically invalid. Returns an empty array if none of the ranges are satisfiable.



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# File 'lib/rack/utils.rb', line 333

def byte_ranges(env, size)
  warn "`byte_ranges` is deprecated, please use `get_byte_ranges`" if $VERBOSE
  get_byte_ranges env['HTTP_RANGE'], size
end

.clean_path_info(path_info) ⇒ Object



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# File 'lib/rack/utils.rb', line 575

def clean_path_info(path_info)
  parts = path_info.split PATH_SEPS

  clean = []

  parts.each do |part|
    next if part.empty? || part == '.'
    part == '..' ? clean.pop : clean << part
  end

  clean.unshift '/' if parts.empty? || parts.first.empty?

  ::File.join clean
end

.clock_timeObject



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# File 'lib/rack/utils.rb', line 83

def clock_time
  Process.clock_gettime(Process::CLOCK_MONOTONIC)
end


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# File 'lib/rack/utils.rb', line 290

def delete_cookie_header!(header, key, value = {})
  header[SET_COOKIE] = add_remove_cookie_to_header(header[SET_COOKIE], key, value)
  nil
end

.escape(s) ⇒ Object

URI escapes. (CGI style space to +)



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# File 'lib/rack/utils.rb', line 30

def escape(s)
  URI.encode_www_form_component(s)
end

.escape_html(string) ⇒ Object

Escape ampersands, brackets and quotes to their HTML/XML entities.



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# File 'lib/rack/utils.rb', line 171

def escape_html(string)
  string.to_s.gsub(ESCAPE_HTML_PATTERN){|c| ESCAPE_HTML[c] }
end

.escape_path(s) ⇒ Object

Like URI escaping, but with %20 instead of +. Strictly speaking this is true URI escaping.



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# File 'lib/rack/utils.rb', line 37

def escape_path(s)
  ::URI::DEFAULT_PARSER.escape s
end

.get_byte_ranges(http_range, size) ⇒ Object



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# File 'lib/rack/utils.rb', line 339

def get_byte_ranges(http_range, size)
  # See <http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35>
  return nil unless http_range && http_range =~ /bytes=([^;]+)/
  ranges = []
  $1.split(/,\s*/).each do |range_spec|
    return nil  unless range_spec =~ /(\d*)-(\d*)/
    r0, r1 = $1, $2
    if r0.empty?
      return nil  if r1.empty?
      # suffix-byte-range-spec, represents trailing suffix of file
      r0 = size - r1.to_i
      r0 = 0  if r0 < 0
      r1 = size - 1
    else
      r0 = r0.to_i
      if r1.empty?
        r1 = size - 1
      else
        r1 = r1.to_i
        return nil  if r1 < r0  # backwards range is syntactically invalid
        r1 = size - 1  if r1 >= size
      end
    end
    ranges << (r0..r1)  if r0 <= r1
  end
  ranges
end

.key_space_limitObject



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# File 'lib/rack/utils.rb', line 74

def self.key_space_limit
  default_query_parser.key_space_limit
end

.key_space_limit=(v) ⇒ Object



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# File 'lib/rack/utils.rb', line 78

def self.key_space_limit=(v)
  self.default_query_parser = self.default_query_parser.new_space_limit(v)
end


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# File 'lib/rack/utils.rb', line 266

def make_delete_cookie_header(header, key, value)
  case header
  when nil, ''
    cookies = []
  when String
    cookies = header.split("\n")
  when Array
    cookies = header
  end

  cookies.reject! { |cookie|
    if value[:domain]
      cookie =~ /\A#{escape(key)}=.*domain=#{value[:domain]}/
    elsif value[:path]
      cookie =~ /\A#{escape(key)}=.*path=#{value[:path]}/
    else
      cookie =~ /\A#{escape(key)}=/
    end
  }

  cookies.join("\n")
end

.param_depth_limitObject



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# File 'lib/rack/utils.rb', line 66

def self.param_depth_limit
  default_query_parser.param_depth_limit
end

.param_depth_limit=(v) ⇒ Object



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# File 'lib/rack/utils.rb', line 70

def self.param_depth_limit=(v)
  self.default_query_parser = self.default_query_parser.new_depth_limit(v)
end

.parse_cookies(env) ⇒ Object



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# File 'lib/rack/utils.rb', line 204

def parse_cookies(env)
  parse_cookies_header env[HTTP_COOKIE]
end

.parse_cookies_header(header) ⇒ Object



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# File 'lib/rack/utils.rb', line 209

def parse_cookies_header(header)
  # According to RFC 2109:
  #   If multiple cookies satisfy the criteria above, they are ordered in
  #   the Cookie header such that those with more specific Path attributes
  #   precede those with less specific.  Ordering with respect to other
  #   attributes (e.g., Domain) is unspecified.
  cookies = parse_query(header, ';,') { |s| unescape(s) rescue s }
  cookies.each_with_object({}) { |(k, v), hash| hash[k] = Array === v ? v.first : v }
end

.parse_nested_query(qs, d = nil) ⇒ Object



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# File 'lib/rack/utils.rb', line 98

def parse_nested_query(qs, d = nil)
  Rack::Utils.default_query_parser.parse_nested_query(qs, d)
end

.parse_query(qs, d = nil, &unescaper) ⇒ Object



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# File 'lib/rack/utils.rb', line 93

def parse_query(qs, d = nil, &unescaper)
  Rack::Utils.default_query_parser.parse_query(qs, d, &unescaper)
end

.q_values(q_value_header) ⇒ Object



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# File 'lib/rack/utils.rb', line 133

def q_values(q_value_header)
  q_value_header.to_s.split(/\s*,\s*/).map do |part|
    value, parameters = part.split(/\s*;\s*/, 2)
    quality = 1.0
    if md = /\Aq=([\d.]+)/.match(parameters)
      quality = md[1].to_f
    end
    [value, quality]
  end
end

.rfc2109(time) ⇒ Object

Modified version of stdlib time.rb Time#rfc2822 to use '%d-%b-%Y' instead of '% %b %Y'. It assumes that the time is in GMT to comply to the RFC 2109.

NOTE: I'm not sure the RFC says it requires GMT, but is ambiguous enough that I'm certain someone implemented only that option. Do not use %a and %b from Time.strptime, it would use localized names for weekday and month.



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# File 'lib/rack/utils.rb', line 323

def rfc2109(time)
  wday = Time::RFC2822_DAY_NAME[time.wday]
  mon = Time::RFC2822_MONTH_NAME[time.mon - 1]
  time.strftime("#{wday}, %d-#{mon}-%Y %H:%M:%S GMT")
end

.rfc2822(time) ⇒ Object



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# File 'lib/rack/utils.rb', line 309

def rfc2822(time)
  time.rfc2822
end

.secure_compare(a, b) ⇒ Object

Constant time string comparison.

NOTE: the values compared should be of fixed length, such as strings that have already been processed by HMAC. This should not be used on variable length plaintext strings because it could leak length info via timing attacks.



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# File 'lib/rack/utils.rb', line 374

def secure_compare(a, b)
  return false unless a.bytesize == b.bytesize

  l = a.unpack("C*")

  r, i = 0, -1
  b.each_byte { |v| r |= v ^ l[i += 1] }
  r == 0
end

.select_best_encoding(available_encodings, accept_encoding) ⇒ Object



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# File 'lib/rack/utils.rb', line 176

def select_best_encoding(available_encodings, accept_encoding)
  # http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html

  expanded_accept_encoding =
    accept_encoding.map { |m, q|
      if m == "*"
        (available_encodings - accept_encoding.map { |m2, _| m2 }).map { |m2| [m2, q] }
      else
        [[m, q]]
      end
    }.inject([]) { |mem, list|
      mem + list
    }

  encoding_candidates = expanded_accept_encoding.sort_by { |_, q| -q }.map { |m, _| m }

  unless encoding_candidates.include?("identity")
    encoding_candidates.push("identity")
  end

  expanded_accept_encoding.each { |m, q|
    encoding_candidates.delete(m) if q == 0.0
  }

  return (encoding_candidates & available_encodings)[0]
end


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# File 'lib/rack/utils.rb', line 260

def set_cookie_header!(header, key, value)
  header[SET_COOKIE] = add_cookie_to_header(header[SET_COOKIE], key, value)
  nil
end

.status_code(status) ⇒ Object



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# File 'lib/rack/utils.rb', line 564

def status_code(status)
  if status.is_a?(Symbol)
    SYMBOL_TO_STATUS_CODE.fetch(status) { raise ArgumentError, "Unrecognized status code #{status.inspect}" }
  else
    status.to_i
  end
end

.unescape(s, encoding = Encoding::UTF_8) ⇒ Object

Unescapes a URI escaped string with encoding. encoding will be the target encoding of the string returned, and it defaults to UTF-8



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# File 'lib/rack/utils.rb', line 52

def unescape(s, encoding = Encoding::UTF_8)
  URI.decode_www_form_component(s, encoding)
end

.unescape_path(s) ⇒ Object

Unescapes the *path* component of a URI. See Rack::Utils.unescape for unescaping query parameters or form components.



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# File 'lib/rack/utils.rb', line 44

def unescape_path(s)
  ::URI::DEFAULT_PARSER.unescape s
end

.valid_path?(path) ⇒ Boolean



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# File 'lib/rack/utils.rb', line 593

def valid_path?(path)
  path.valid_encoding? && !path.include?(NULL_BYTE)
end