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
URI_PARSER = 
defined?(::URI::RFC2396_PARSER) ? ::URI::RFC2396_PARSER : ::URI::DEFAULT_PARSER
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 -rcsv -e "puts CSV.parse(STDIN, headers: true) \
  .reject {|v| v['Description'] == 'Unassigned' or v['Description'].include? '(' } \
  .map {|v| %Q/#{v['Value']} => '#{v['Description']}'/ }.join(','+?\n)"

{
  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 => 'Content Too Large',
  414 => 'URI Too Long',
  415 => 'Unsupported Media Type',
  416 => 'Range Not Satisfiable',
  417 => 'Expectation Failed',
  421 => 'Misdirected Request',
  422 => 'Unprocessable Content',
  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',
  511 => 'Network Authentication Required'
}
STATUS_WITH_NO_ENTITY_BODY =

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


      
        
SYMBOL_TO_STATUS_CODE =
          
        

        

      
        
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 30

def default_query_parser
  @default_query_parser
end

    		
  





    
      
      
      

  

  
    .multipart_file_limit  ⇒ Object 
  

  
    Also known as:
    multipart_part_limit
    
  

  




  

    

Returns the value of attribute multipart_file_limit.



  





  



  

    
      


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# File 'lib/rack/utils.rb', line 65

def multipart_file_limit
  @multipart_file_limit
end

    		
  





    
      
      
      

  

  
    .multipart_total_part_limit  ⇒ Object 
  

  

  




  

    

Returns the value of attribute multipart_total_part_limit.



  





  



  

    
      


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# File 'lib/rack/utils.rb', line 63

def multipart_total_part_limit
  @multipart_total_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 167

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 120

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 110

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 409

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 609

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 367

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 363

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 391

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 40

def escape(s)
  URI.encode_www_form_component(s)
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 46

def escape_path(s)
  URI_PARSER.escape s
end

    		
  





    
      

  

  
    .forwarded_values(forwarded_header)  ⇒ Object 
  

  

  




  

    
      


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# File 'lib/rack/utils.rb', line 149

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

  forwarded_header.split(';').each_with_object({}) do |field, values|
    field.split(',').each do |pair|
      pair = pair.split('=').map(&:strip).join('=')
      return nil unless pair =~ /\A(by|for|host|proto)="?([^"]+)"?\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 413

def get_byte_ranges(http_range, size)
  # See <http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35>
  # Ignore Range when file size is 0 to avoid a 416 error.
  return nil if size.zero?
  return nil unless http_range && http_range =~ /bytes=([^;]+)/
  ranges = []
  $1.split(/,\s*/).each do |range_spec|
    return nil unless range_spec.include?('-')
    range = range_spec.split('-')
    r0, r1 = range[0], range[1]
    if r0.nil? || r0.empty?
      return nil if r1.nil?
      # 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.nil?
        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

  return [] if ranges.map(&:size).sum > size

  ranges
end

    		
  





    
      

  

  
    .param_depth_limit  ⇒ Object 
  

  

  




  

    
      


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# File 'lib/rack/utils.rb', line 82

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 86

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 253

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 234

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 106

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 102

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 138

def q_values(q_value_header)
  q_value_header.to_s.split(',').map do |part|
    value, parameters = part.split(';', 2).map(&:strip)
    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 402

def rfc2822(time)
  time.rfc2822
end

    		
  





    
      

  

  
    .select_best_encoding(available_encodings, accept_encoding)  ⇒ Object 
  

  

  




  

    
      


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# File 'lib/rack/utils.rb', line 192

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 294

def set_cookie_header(key, value)
  case value
  when Hash
    key = escape_cookie_key(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 :same_site value: #{value[:same_site].inspect}"
      end
    partitioned = "; partitioned" if value[:partitioned]
    value = value[:value]
  else
    key = escape_cookie_key(key)
  end

  value = [value] unless Array === value

  return "#{key}=#{value.map { |v| escape v }.join('&')}#{domain}" \
    "#{path}#{max_age}#{expires}#{secure}#{httponly}#{same_site}#{partitioned}"
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 337

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 589

def status_code(status)
  if status.is_a?(Symbol)
    SYMBOL_TO_STATUS_CODE.fetch(status) do
      fallback_code = OBSOLETE_SYMBOLS_TO_STATUS_CODES.fetch(status) { raise ArgumentError, "Unrecognized status code #{status.inspect}" }
      message = "Status code #{status.inspect} is deprecated and will be removed in a future version of Rack."
      if canonical_symbol = OBSOLETE_SYMBOL_MAPPINGS[status]
        # message = "#{message} Please use #{canonical_symbol.inspect} instead."
        # For now, let's not emit any warning when there is a mapping.
      else
        warn message, uplevel: 3
      end
      fallback_code
    end
  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 58

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 52

def unescape_path(s)
  URI_PARSER.unescape s
end

    		
  





    
      

  

  
    .valid_path?(path)  ⇒ Boolean 
  

  

  




  

    

  





  

Returns:


    
  
    
  • 
      
      
        (Boolean)
      
      
      
    
    • 
  





  

    
      


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# File 'lib/rack/utils.rb', line 626

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 96

def clock_time
  Process.clock_gettime(Process::CLOCK_MONOTONIC)
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 187

def escape_html(string)
  CGI.escapeHTML(string.to_s)
end

    		
  





    
      

  

  
    #secure_compare(a, b)  ⇒ Object 
  

  

  




  

    

:nocov:



  





  



  

    
      


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# File 'lib/rack/utils.rb', line 455

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

  OpenSSL.fixed_length_secure_compare(a, b)
end