Module: Rack::Utils

Included in:
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

Constant Summary collapse

ParameterTypeError = 
QueryParser::ParameterTypeError
InvalidParameterError = 
QueryParser::InvalidParameterError
ParamsTooDeepError = 
QueryParser::ParamsTooDeepError
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',
  306 => '(Unused)',
  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

Instance Method Summary collapse

Class Attribute Details

.default_query_parser ⇒ Object

Returns the value of attribute default_query_parser.


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# File 'lib/rack/utils.rb', line 28

def default_query_parser
  @default_query_parser
end

.multipart_part_limit ⇒ Object

Returns the value of attribute multipart_part_limit.


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# File 'lib/rack/utils.rb', line 61

def multipart_part_limit
  @multipart_part_limit
end

Class Method Details

.best_q_match(q_value_header, available_mimes) ⇒ Object

Return best accept value to use, based on the algorithm in RFC 2616 Section 14. If there are multiple best matches (same specificity and quality), the value returned is arbitrary.


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# File 'lib/rack/utils.rb', line 153

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&.first
end

.build_nested_query(value, prefix = nil) ⇒ Object 


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# File 'lib/rack/utils.rb', line 107

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}[#{k}]" : k)
    }.delete_if(&:empty?).join('&')
  when nil
    escape(prefix)
  else
    raise ArgumentError, "value must be a Hash" if prefix.nil?
    "#{escape(prefix)}=#{escape(value)}"
  end
end

.build_query(params) ⇒ Object 


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# File 'lib/rack/utils.rb', line 97

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 384

def byte_ranges(env, size)
  get_byte_ranges env['HTTP_RANGE'], size
end

.clean_path_info(path_info) ⇒ Object 


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# File 'lib/rack/utils.rb', line 556

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_path = clean.join(::File::SEPARATOR)
  clean_path.prepend("/") if parts.empty? || parts.first.empty?
  clean_path
end

.delete_cookie_header!(headers, key, value = {}) ⇒ Object 


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# File 'lib/rack/utils.rb', line 342

def delete_cookie_header!(headers, key, value = {})
  headers[SET_COOKIE] = delete_set_cookie_header!(headers[SET_COOKIE], key, value)

  return nil
end

.delete_set_cookie_header(key, value = {}) ⇒ Object

:call-seq:

delete_set_cookie_header(key, value = {}) -> encoded string

Generate an encoded string based on the given key and value using set_cookie_header for the purpose of causing the specified cookie to be deleted. The value may be an instance of Hash and can include attributes as outlined by set_cookie_header. The encoded cookie will have a max_age of 0 seconds, an expires date in the past and an empty value. When used with the set-cookie header, it will cause the client to remove any matching cookie.

delete_set_cookie_header("myname")
# => "myname=; max-age=0; expires=Thu, 01 Jan 1970 00:00:00 GMT"


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# File 'lib/rack/utils.rb', line 338

def delete_set_cookie_header(key, value = {})
  set_cookie_header(key, value.merge(max_age: '0', expires: Time.at(0), value: ''))
end

.delete_set_cookie_header!(header, key, value = {}) ⇒ Object

:call-seq:

delete_set_cookie_header!(header, key, value = {}) -> header value

Set an expired cookie in the specified headers with the given cookie key and value using delete_set_cookie_header. This causes the client to immediately delete the specified cookie.

delete_set_cookie_header!(nil, "mycookie")
# => "mycookie=; max-age=0; expires=Thu, 01 Jan 1970 00:00:00 GMT"

If the header is non-nil, it will be modified in place.

header = []
delete_set_cookie_header!(header, "mycookie")
# => ["mycookie=; max-age=0; expires=Thu, 01 Jan 1970 00:00:00 GMT"]
header
# => ["mycookie=; max-age=0; expires=Thu, 01 Jan 1970 00:00:00 GMT"]


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# File 'lib/rack/utils.rb', line 366

def delete_set_cookie_header!(header, key, value = {})
  if header
    header = Array(header)
    header << delete_set_cookie_header(key, value)
  else
    header = delete_set_cookie_header(key, value)
  end

  return header
end

.escape(s) ⇒ Object

URI escapes. (CGI style space to +)


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# File 'lib/rack/utils.rb', line 38

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 178

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 44

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

.forwarded_values(forwarded_header) ⇒ Object 


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# File 'lib/rack/utils.rb', line 136

def forwarded_values(forwarded_header)
  return nil unless forwarded_header
  forwarded_header = forwarded_header.to_s.gsub("\n", ";")

  forwarded_header.split(/\s*;\s*/).each_with_object({}) do |field, values|
    field.split(/\s*,\s*/).each do |pair|
      return nil unless pair =~ /\A\s*(by|for|host|proto)\s*=\s*"?([^"]+)"?\s*\Z/i
      (values[$1.downcase.to_sym] ||= []) << $2
    end
  end
end

.get_byte_ranges(http_range, size) ⇒ Object 


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# File 'lib/rack/utils.rb', line 388

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

.param_depth_limit ⇒ Object 


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# File 'lib/rack/utils.rb', line 69

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 73

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

.parse_cookies(env) ⇒ Object

:call-seq:

parse_cookies(env) -> hash

Parse cookies from the provided request environment using parse_cookies_header. Returns a map of cookie key to cookie value.

parse_cookies({'HTTP_COOKIE' => 'myname=myvalue'})
# => {'myname' => 'myvalue'}


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# File 'lib/rack/utils.rb', line 243

def parse_cookies(env)
  parse_cookies_header env[HTTP_COOKIE]
end

.parse_cookies_header(value) ⇒ Object

:call-seq:

parse_cookies_header(value) -> hash

Parse cookies from the provided header value according to RFC6265. The syntax for cookie headers only supports semicolons. Returns a map of cookie key to cookie value.

parse_cookies_header('myname=myvalue; max-age=0')
# => {"myname"=>"myvalue", "max-age"=>"0"}


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# File 'lib/rack/utils.rb', line 224

def parse_cookies_header(value)
  return {} unless value

  value.split(/; */n).each_with_object({}) do |cookie, cookies|
    next if cookie.empty?
    key, value = cookie.split('=', 2)
    cookies[key] = (unescape(value) rescue value) unless cookies.key?(key)
  end
end

.parse_nested_query(qs, d = nil) ⇒ Object 


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

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 89

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 125

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 parameters && (md = /\Aq=([\d.]+)/.match(parameters))
      quality = md[1].to_f
    end
    [value, quality]
  end
end

.rfc2822(time) ⇒ Object 


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# File 'lib/rack/utils.rb', line 377

def rfc2822(time)
  time.rfc2822
end

.select_best_encoding(available_encodings, accept_encoding) ⇒ Object 


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# File 'lib/rack/utils.rb', line 182

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

  expanded_accept_encoding = []

  accept_encoding.each do |m, q|
    preference = available_encodings.index(m) || available_encodings.size

    if m == "*"
      (available_encodings - accept_encoding.map(&:first)).each do |m2|
        expanded_accept_encoding << [m2, q, preference]
      end
    else
      expanded_accept_encoding << [m, q, preference]
    end
  end

  encoding_candidates = expanded_accept_encoding
    .sort_by { |_, q, p| [-q, p] }
    .map!(&:first)

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

  expanded_accept_encoding.each do |m, q|
    encoding_candidates.delete(m) if q == 0.0
  end

  (encoding_candidates & available_encodings)[0]
end

.set_cookie_header(key, value) ⇒ Object

:call-seq:

set_cookie_header(key, value) -> encoded string

Generate an encoded string using the provided key and value suitable for the set-cookie header according to RFC6265. The value may be an instance of either String or Hash.

If the cookie value is an instance of Hash, it considers the following cookie attribute keys: domain, max_age, expires (must be instance of Time), secure, http_only, same_site and value. For more details about the interpretation of these fields, consult [RFC6265 Section 5.2](datatracker.ietf.org/doc/html/rfc6265#section-5.2).

An extra cookie attribute escape_key can be provided to control whether or not the cookie key is URL encoded. If explicitly set to false, the cookie key name will not be url encoded (escaped). The default is true.

set_cookie_header("myname", "myvalue")
# => "myname=myvalue"

set_cookie_header("myname", {value: "myvalue", max_age: 10})
# => "myname=myvalue; max-age=10"


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# File 'lib/rack/utils.rb', line 270

def set_cookie_header(key, value)
  case value
  when Hash
    key = escape(key) unless value[:escape_key] == false
    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 :none, 'None', :None
        '; SameSite=None'
      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]
  else
    key = escape(key)
  end

  value = [value] unless Array === value

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

.set_cookie_header!(headers, key, value) ⇒ Object

:call-seq:

set_cookie_header!(headers, key, value) -> header value

Append a cookie in the specified headers with the given cookie key and value using set_cookie_header.

If the headers already contains a set-cookie key, it will be converted to an Array if not already, and appended to.


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# File 'lib/rack/utils.rb', line 312

def set_cookie_header!(headers, key, value)
  if header = headers[SET_COOKIE]
    if header.is_a?(Array)
      header << set_cookie_header(key, value)
    else
      headers[SET_COOKIE] = [header, set_cookie_header(key, value)]
    end
  else
    headers[SET_COOKIE] = set_cookie_header(key, value)
  end
end

.status_code(status) ⇒ Object 


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# File 'lib/rack/utils.rb', line 546

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 56

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 50

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

.valid_path?(path) ⇒ Boolean

Returns:

  • (Boolean) 

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# File 'lib/rack/utils.rb', line 573

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

Instance Method Details

#clock_time ⇒ Object

:nocov:


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

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

#secure_compare(a, b) ⇒ Object

:nocov:


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# File 'lib/rack/utils.rb', line 424

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

  OpenSSL.fixed_length_secure_compare(a, b)
end