summaryrefslogtreecommitdiff
path: root/lib/cgi/util.rb
blob: 4986e544e0144453b621cbdb2c0de850897793a3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
# frozen_string_literal: true
class CGI
  module Util; end
  include Util
  extend Util
end
module CGI::Util
  @@accept_charset = Encoding::UTF_8 unless defined?(@@accept_charset)

  # URL-encode a string into application/x-www-form-urlencoded.
  # Space characters (+" "+) are encoded with plus signs (+"+"+)
  #   url_encoded_string = CGI.escape("'Stop!' said Fred")
  #      # => "%27Stop%21%27+said+Fred"
  def escape(string)
    encoding = string.encoding
    buffer = string.b
    buffer.gsub!(/([^ a-zA-Z0-9_.\-~]+)/) do |m|
      '%' + m.unpack('H2' * m.bytesize).join('%').upcase
    end
    buffer.tr!(' ', '+')
    buffer.force_encoding(encoding)
  end

  # URL-decode an application/x-www-form-urlencoded string with encoding(optional).
  #   string = CGI.unescape("%27Stop%21%27+said+Fred")
  #      # => "'Stop!' said Fred"
  def unescape(string, encoding = @@accept_charset)
    str = string.tr('+', ' ')
    str = str.b
    str.gsub!(/((?:%[0-9a-fA-F]{2})+)/) do |m|
      [m.delete('%')].pack('H*')
    end
    str.force_encoding(encoding)
    str.valid_encoding? ? str : str.force_encoding(string.encoding)
  end

  # URL-encode a string following RFC 3986
  # Space characters (+" "+) are encoded with (+"%20"+)
  #   url_encoded_string = CGI.escapeURIComponent("'Stop!' said Fred")
  #      # => "%27Stop%21%27%20said%20Fred"
  def escapeURIComponent(string)
    encoding = string.encoding
    buffer = string.b
    buffer.gsub!(/([^a-zA-Z0-9_.\-~]+)/) do |m|
      '%' + m.unpack('H2' * m.bytesize).join('%').upcase
    end
    buffer.force_encoding(encoding)
  end
  alias escape_uri_component escapeURIComponent

  # URL-decode a string following RFC 3986 with encoding(optional).
  #   string = CGI.unescapeURIComponent("%27Stop%21%27+said%20Fred")
  #      # => "'Stop!'+said Fred"
  def unescapeURIComponent(string, encoding = @@accept_charset)
    str = string.b
    str.gsub!(/((?:%[0-9a-fA-F]{2})+)/) do |m|
      [m.delete('%')].pack('H*')
    end
    str.force_encoding(encoding)
    str.valid_encoding? ? str : str.force_encoding(string.encoding)
  end

  alias unescape_uri_component unescapeURIComponent

  # The set of special characters and their escaped values
  TABLE_FOR_ESCAPE_HTML__ = {
    "'" => ''',
    '&' => '&',
    '"' => '"',
    '<' => '&lt;',
    '>' => '&gt;',
  }

  # Escape special characters in HTML, namely '&\"<>
  #   CGI.escapeHTML('Usage: foo "bar" <baz>')
  #      # => "Usage: foo &quot;bar&quot; &lt;baz&gt;"
  def escapeHTML(string)
    enc = string.encoding
    unless enc.ascii_compatible?
      if enc.dummy?
        origenc = enc
        enc = Encoding::Converter.asciicompat_encoding(enc)
        string = enc ? string.encode(enc) : string.b
      end
      table = Hash[TABLE_FOR_ESCAPE_HTML__.map {|pair|pair.map {|s|s.encode(enc)}}]
      string = string.gsub(/#{"['&\"<>]".encode(enc)}/, table)
      string.encode!(origenc) if origenc
      string
    else
      string = string.b
      string.gsub!(/['&\"<>]/, TABLE_FOR_ESCAPE_HTML__)
      string.force_encoding(enc)
    end
  end

  # TruffleRuby runs the pure-Ruby variant faster, do not use the C extension there
  unless RUBY_ENGINE == 'truffleruby'
    begin
      require 'cgi/escape'
    rescue LoadError
    end
  end

  # Unescape a string that has been HTML-escaped
  #   CGI.unescapeHTML("Usage: foo &quot;bar&quot; &lt;baz&gt;")
  #      # => "Usage: foo \"bar\" <baz>"
  def unescapeHTML(string)
    enc = string.encoding
    unless enc.ascii_compatible?
      if enc.dummy?
        origenc = enc
        enc = Encoding::Converter.asciicompat_encoding(enc)
        string = enc ? string.encode(enc) : string.b
      end
      string = string.gsub(Regexp.new('&(apos|amp|quot|gt|lt|#[0-9]+|#x[0-9A-Fa-f]+);'.encode(enc))) do
        case $1.encode(Encoding::US_ASCII)
        when 'apos'                then "'".encode(enc)
        when 'amp'                 then '&'.encode(enc)
        when 'quot'                then '"'.encode(enc)
        when 'gt'                  then '>'.encode(enc)
        when 'lt'                  then '<'.encode(enc)
        when /\A#0*(\d+)\z/        then $1.to_i.chr(enc)
        when /\A#x([0-9a-f]+)\z/i  then $1.hex.chr(enc)
        end
      end
      string.encode!(origenc) if origenc
      return string
    end
    return string unless string.include? '&'
    charlimit = case enc
                when Encoding::UTF_8; 0x10ffff
                when Encoding::ISO_8859_1; 256
                else 128
                end
    string = string.b
    string.gsub!(/&(apos|amp|quot|gt|lt|\#[0-9]+|\#[xX][0-9A-Fa-f]+);/) do
      match = $1.dup
      case match
      when 'apos'                then "'"
      when 'amp'                 then '&'
      when 'quot'                then '"'
      when 'gt'                  then '>'
      when 'lt'                  then '<'
      when /\A#0*(\d+)\z/
        n = $1.to_i
        if n < charlimit
          n.chr(enc)
        else
          "&##{$1};"
        end
      when /\A#x([0-9a-f]+)\z/i
        n = $1.hex
        if n < charlimit
          n.chr(enc)
        else
          "&#x#{$1};"
        end
      else
        "&#{match};"
      end
    end
    string.force_encoding enc
  end

  # Synonym for CGI.escapeHTML(str)
  alias escape_html escapeHTML

  # Synonym for CGI.unescapeHTML(str)
  alias unescape_html unescapeHTML

  # Escape only the tags of certain HTML elements in +string+.
  #
  # Takes an element or elements or array of elements.  Each element
  # is specified by the name of the element, without angle brackets.
  # This matches both the start and the end tag of that element.
  # The attribute list of the open tag will also be escaped (for
  # instance, the double-quotes surrounding attribute values).
  #
  #   print CGI.escapeElement('<BR><A HREF="url"></A>', "A", "IMG")
  #     # "<BR>&lt;A HREF=&quot;url&quot;&gt;&lt;/A&gt"
  #
  #   print CGI.escapeElement('<BR><A HREF="url"></A>', ["A", "IMG"])
  #     # "<BR>&lt;A HREF=&quot;url&quot;&gt;&lt;/A&gt"
  def escapeElement(string, *elements)
    elements = elements[0] if elements[0].kind_of?(Array)
    unless elements.empty?
      string.gsub(/<\/?(?:#{elements.join("|")})(?!\w)(?:.|\n)*?>/i) do
        CGI.escapeHTML($&)
      end
    else
      string
    end
  end

  # Undo escaping such as that done by CGI.escapeElement()
  #
  #   print CGI.unescapeElement(
  #           CGI.escapeHTML('<BR><A HREF="url"></A>'), "A", "IMG")
  #     # "&lt;BR&gt;<A HREF="url"></A>"
  #
  #   print CGI.unescapeElement(
  #           CGI.escapeHTML('<BR><A HREF="url"></A>'), ["A", "IMG"])
  #     # "&lt;BR&gt;<A HREF="url"></A>"
  def unescapeElement(string, *elements)
    elements = elements[0] if elements[0].kind_of?(Array)
    unless elements.empty?
      string.gsub(/&lt;\/?(?:#{elements.join("|")})(?!\w)(?:.|\n)*?&gt;/i) do
        unescapeHTML($&)
      end
    else
      string
    end
  end

  # Synonym for CGI.escapeElement(str)
  alias escape_element escapeElement

  # Synonym for CGI.unescapeElement(str)
  alias unescape_element unescapeElement

  # Format a +Time+ object as a String using the format specified by RFC 1123.
  #
  #   CGI.rfc1123_date(Time.now)
  #     # Sat, 01 Jan 2000 00:00:00 GMT
  def rfc1123_date(time)
    time.getgm.strftime("%a, %d %b %Y %T GMT")
  end

  # Prettify (indent) an HTML string.
  #
  # +string+ is the HTML string to indent.  +shift+ is the indentation
  # unit to use; it defaults to two spaces.
  #
  #   print CGI.pretty("<HTML><BODY></BODY></HTML>")
  #     # <HTML>
  #     #   <BODY>
  #     #   </BODY>
  #     # </HTML>
  #
  #   print CGI.pretty("<HTML><BODY></BODY></HTML>", "\t")
  #     # <HTML>
  #     #         <BODY>
  #     #         </BODY>
  #     # </HTML>
  #
  def pretty(string, shift = "  ")
    lines = string.gsub(/(?!\A)<.*?>/m, "\n\\0").gsub(/<.*?>(?!\n)/m, "\\0\n")
    end_pos = 0
    while end_pos = lines.index(/^<\/(\w+)/, end_pos)
      element = $1.dup
      start_pos = lines.rindex(/^\s*<#{element}/i, end_pos)
      lines[start_pos ... end_pos] = "__" + lines[start_pos ... end_pos].gsub(/\n(?!\z)/, "\n" + shift) + "__"
    end
    lines.gsub(/^((?:#{Regexp::quote(shift)})*)__(?=<\/?\w)/, '\1')
  end

  alias h escapeHTML
end