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 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',
  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',
  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',
  510 => 'Not Extended',
  511 => 'Network Authentication Required'
}
STATUS_WITH_NO_ENTITY_BODY =

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

Set.new((100..199).to_a << 204 << 205 << 304)
SYMBOL_TO_STATUS_CODE = 

      
        
PATH_SEPS =
          
        

        
Regexp.union(*[::File::SEPARATOR, ::File::ALT_SEPARATOR].compact)

      
        
NULL_BYTE =
          
        

        
"\0".freeze

      
    

  




  
Class Attribute Summary collapse

  




  
    

      Class 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 21

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 56

def multipart_part_limit
  @multipart_part_limit
end

    		
  





    
  



  

    
Class Method Details


    
      

  


  

    
      


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# File 'lib/rack/utils.rb', line 218

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]
    # There is an RFC mess in the area of date formatting for Cookies. Not
    # only are there contradicting RFCs and examples within RFC text, but
    # there are also numerous conflicting names of fields and partially
    # cross-applicable specifications.
    #
    # These are best described in RFC 2616 3.3.1. This RFC text also
    # specifies that RFC 822 as updated by RFC 1123 is preferred. That is a
    # fixed length format with space-date delimited fields.
    #
    # See also RFC 1123 section 5.2.14.
    #
    # RFC 6265 also specifies "sane-cookie-date" as RFC 1123 date, defined
    # in RFC 2616 3.3.1. RFC 6265 also gives examples that clearly denote
    # the space delimited format. These formats are compliant with RFC 2822.
    #
    # For reference, all involved RFCs are:
    # RFC 822
    # RFC 1123
    # RFC 2109
    # RFC 2616
    # RFC 2822
    # RFC 2965
    # RFC 6265
    expires = "; expires=" +
      rfc2822(value[:expires].clone.gmtime) 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'.freeze
      when true, :strict, 'Strict', :Strict
        '; SameSite=Strict'.freeze
      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

    		
  





    
      

  

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

  

  




  

    

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 320

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 143

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 112

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 101

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 355

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 596

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_time  ⇒ Object 
  

  

  




  

    
      


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# File 'lib/rack/utils.rb', line 81

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

    		
  





    
      

  

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

  

  




  

    
      


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

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 28

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 169

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 35

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 361

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_limit  ⇒ Object 
  

  

  




  

    
      


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# File 'lib/rack/utils.rb', line 72

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 76

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

    		
  





    
      

  

  
    .make_delete_cookie_header(header, key, value)  ⇒ Object 
  

  

  




  

    
      


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# File 'lib/rack/utils.rb', line 288

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_limit  ⇒ Object 
  

  

  




  

    
      


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# File 'lib/rack/utils.rb', line 64

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 68

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 202

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 207

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 96

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 91

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 131

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 345

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 331

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 396

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 174

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

    		
  





    
      

  

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

  

  




  

    
      


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# File 'lib/rack/utils.rb', line 282

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 585

def status_code(status)
  if status.is_a?(Symbol)
    SYMBOL_TO_STATUS_CODE[status] || 500
  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 50

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 42

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 614

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