Module: Rack::Utils

Included in:
Chunked, ContentLength
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

Modules: Multipart Classes: Context, HeaderHash

Constant Summary collapse

DEFAULT_SEP = 
/[&;] */n
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 http://www.iana.org/assignments/http-status-codes | \
  ruby -ane 'm = /^(\d{3}) +(\S[^\[(]+)/.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',
  226  => 'IM Used',
  300  => 'Multiple Choices',
  301  => 'Moved Permanently',
  302  => 'Found',
  303  => 'See Other',
  304  => 'Not Modified',
  305  => 'Use Proxy',
  306  => 'Reserved',
  307  => 'Temporary 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  => 'Request Entity Too Large',
  414  => 'Request-URI Too Long',
  415  => 'Unsupported Media Type',
  416  => 'Requested Range Not Satisfiable',
  417  => 'Expectation Failed',
  422  => 'Unprocessable Entity',
  423  => 'Locked',
  424  => 'Failed Dependency',
  426  => 'Upgrade Required',
  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',
  510  => 'Not Extended',
}
STATUS_WITH_NO_ENTITY_BODY =

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

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





Class Method Summary
collapse






Class Method Details





.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))
    }.join("&")
  when String
    raise ArgumentError, "value must be a Hash" if prefix.nil?
    "#{prefix}=#{escape(value)}"
  else
    prefix
  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
      "#{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 268

def byte_ranges(env, size)
  # See <http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35>
  http_range = env['HTTP_RANGE']
  return nil unless http_range
  ranges = []
  http_range.split(/,\s*/).each do |range_spec|
    matches = range_spec.match(/bytes=(\d*)-(\d*)/)
    return nil  unless matches
    r0,r1 = matches[1], matches[2]
    if r0.empty?
      return nil  if r1.empty?
      # suffix-byte-range-spec, represents trailing suffix of file
      r0 = [size - r1.to_i, 0].max
      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












.bytesize(string) ⇒ Object










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# File 'lib/rack/utils.rb', line 239

def bytesize(string)
  string.bytesize
end












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










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# File 'lib/rack/utils.rb', line 208

def delete_cookie_header!(header, key, value = {})
  case header["Set-Cookie"]
  when nil, ''
    cookies = []
  when String
    cookies = header["Set-Cookie"].split("\n")
  when Array
    cookies = header["Set-Cookie"]
  end

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

  header["Set-Cookie"] = cookies.join("\n")

  set_cookie_header!(header, key,
             {:value => '', :path => nil, :domain => nil,
               :expires => Time.at(0) }.merge(value))

  nil
end












.escape(s) ⇒ Object







Performs URI escaping so that you can construct proper query strings faster. Use this rather than the cgi.rb version since it’s faster. (Stolen from Camping).















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# File 'lib/rack/utils.rb', line 15

def escape(s)
  s.to_s.gsub(/([^ a-zA-Z0-9_.-]+)/u) {
    '%'+$1.unpack('H2'*bytesize($1)).join('%').upcase
  }.tr(' ', '+')
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 142

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












.normalize_params(params, name, v = nil) ⇒ Object










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

def normalize_params(params, name, v = nil)
  name =~ %r(\A[\[\]]*([^\[\]]+)\]*)
  k = $1 || ''
  after = $' || ''

  return if k.empty?

  if after == ""
    params[k] = v
  elsif after == "[]"
    params[k] ||= []
    raise TypeError, "expected Array (got #{params[k].class.name}) for param `#{k}'" unless params[k].is_a?(Array)
    params[k] << v
  elsif after =~ %r(^\[\]\[([^\[\]]+)\]$) || after =~ %r(^\[\](.+)$)
    child_key = $1
    params[k] ||= []
    raise TypeError, "expected Array (got #{params[k].class.name}) for param `#{k}'" unless params[k].is_a?(Array)
    if params[k].last.is_a?(Hash) && !params[k].last.key?(child_key)
      normalize_params(params[k].last, child_key, v)
    else
      params[k] << normalize_params({}, child_key, v)
    end
  else
    params[k] ||= {}
    raise TypeError, "expected Hash (got #{params[k].class.name}) for param `#{k}'" unless params[k].is_a?(Hash)
    params[k] = normalize_params(params[k], after, v)
  end

  return params
end












.parse_nested_query(qs, d = nil) ⇒ Object










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# File 'lib/rack/utils.rb', line 57

def parse_nested_query(qs, d = nil)
  params = {}

  (qs || '').split(d ? /[#{d}] */n : DEFAULT_SEP).each do |p|
    k, v = unescape(p).split('=', 2)
    normalize_params(params, k, v)
  end

  return params
end












.parse_query(qs, d = nil) ⇒ Object







Stolen from Mongrel, with some small modifications: Parses a query string by breaking it up at the ‘&’ and ‘;’ characters. You can also use this to parse cookies by changing the characters used in the second parameter (which defaults to ‘&;’).















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

def parse_query(qs, d = nil)
  params = {}

  (qs || '').split(d ? /[#{d}] */n : DEFAULT_SEP).each do |p|
    k, v = p.split('=', 2).map { |x| unescape(x) }
    if cur = params[k]
      if cur.class == Array
        params[k] << v
      else
        params[k] = [cur, v]
      end
    else
      params[k] = v
    end
  end

  return params
end












.rfc2822(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 ambigous 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 258

def rfc2822(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












.select_best_encoding(available_encodings, accept_encoding) ⇒ Object










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# File 'lib/rack/utils.rb', line 147

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.find_all { |m, q|
    q == 0.0
  }.each { |m, _|
    encoding_candidates.delete(m)
  }

  return (encoding_candidates & available_encodings)[0]
end












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










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# File 'lib/rack/utils.rb', line 177

def set_cookie_header!(header, key, value)
  case value
  when Hash
    domain  = "; domain="  + value[:domain] if value[:domain]
    path    = "; path="    + value[:path]   if value[:path]
    # According to RFC 2109, we need dashes here.
    # N.B.: cgi.rb uses spaces...
    expires = "; expires=" +
      rfc2822(value[:expires].clone.gmtime) if value[:expires]
    secure = "; secure"  if value[:secure]
    httponly = "; HttpOnly" if value[:httponly]
    value = value[:value]
  end
  value = [value] unless Array === value
  cookie = escape(key) + "=" +
    value.map { |v| escape v }.join("&") +
    "#{domain}#{path}#{expires}#{secure}#{httponly}"

  case header["Set-Cookie"]
  when nil, ''
    header["Set-Cookie"] = cookie
  when String
    header["Set-Cookie"] = [header["Set-Cookie"], cookie].join("\n")
  when Array
    header["Set-Cookie"] = (header["Set-Cookie"] + [cookie]).join("\n")
  end

  nil
end












.status_code(status) ⇒ Object










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# File 'lib/rack/utils.rb', line 458

def status_code(status)
  if status.is_a?(Symbol)
    SYMBOL_TO_STATUS_CODE[status] || 500
  else
    status.to_i
  end
end












.unescape(s) ⇒ Object







Unescapes a URI escaped string. (Stolen from Camping).















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

def unescape(s)
  s.tr('+', ' ').gsub(/((?:%[0-9a-fA-F]{2})+)/n){
    [$1.delete('%')].pack('H*')
  }
end