Class: Mail::Header

Inherits:
Object show all
Includes:
Enumerable, Patterns, Utilities
Defined in:
lib/mail/header.rb

Overview

Provides access to a header object.

Per RFC2822

2.2. Header Fields

 Header fields are lines composed of a field name, followed by a colon
 (":"), followed by a field body, and terminated by CRLF.  A field
 name MUST be composed of printable US-ASCII characters (i.e.,
 characters that have values between 33 and 126, inclusive), except
 colon.  A field body may be composed of any US-ASCII characters,
 except for CR and LF.  However, a field body may contain CRLF when
 used in header "folding" and  "unfolding" as described in section
 2.2.3.  All field bodies MUST conform to the syntax described in
 sections 3 and 4 of this standard.

Constant Summary collapse

LIMITED_FIELDS = 
%w[ date from sender reply-to to cc bcc 
message-id in-reply-to references subject
return-path content-type mime-version
content-transfer-encoding content-description 
content-id content-disposition content-location]
@@maximum_amount = 
1000

Constants included from Patterns

Patterns::ATOM_UNSAFE, Patterns::CONTROL_CHAR, Patterns::CRLF, Patterns::FIELD_BODY, Patterns::FIELD_LINE, Patterns::FIELD_NAME, Patterns::FWS, Patterns::HEADER_LINE, Patterns::PHRASE_UNSAFE, Patterns::QP_SAFE, Patterns::QP_UNSAFE, Patterns::TEXT, Patterns::TOKEN_UNSAFE, Patterns::WSP

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Utilities

#atom_safe?, #bracket, #capitalize_field, #constantize, #dasherize, #dquote, #escape_paren, #map_lines, #map_with_index, #match_to_s, #paren, #quote_atom, #quote_phrase, #quote_token, #token_safe?, #unbracket, #underscoreize, #unparen, #unquote, #uri_escape, #uri_parser, #uri_unescape

Constructor Details

#initialize(header_text = nil, charset = nil) ⇒ Header

Creates a new header object.

Accepts raw text or nothing. If given raw text will attempt to parse it and split it into the various fields, instantiating each field as it goes.

If it finds a field that should be a structured field (such as content type), but it fails to parse it, it will simply make it an unstructured field and leave it alone. This will mean that the data is preserved but no automatic processing of that field will happen. If you find one of these cases, please make a patch and send it in, or at the least, send me the example so we can fix it.



50
51
52
53
54
55
 
# File 'lib/mail/header.rb', line 50

def initialize(header_text = nil, charset = nil)
  @errors = []
  @charset = charset
  self.raw_source = header_text.to_crlf
  split_header if header_text
end

Class Method Details

.maximum_amount ⇒ Object

Large amount of headers in Email might create extra high CPU load Use this parameter to limit number of headers that will be parsed by mail library. Default: 1000



30
31
32
 
# File 'lib/mail/header.rb', line 30

def self.maximum_amount
  @@maximum_amount
end

.maximum_amount=(value) ⇒ Object 



34
35
36
 
# File 'lib/mail/header.rb', line 34

def self.maximum_amount=(value)
  @@maximum_amount = value
end

Instance Method Details

#[](name) ⇒ Object

3.6. Field definitions

The following table indicates limits on the number of times each
field may occur in a message header as well as any special
limitations on the use of those fields.  An asterisk next to a value
in the minimum or maximum column indicates that a special restriction
appears in the Notes column.

<snip table from 3.6>

As per RFC, many fields can appear more than once, we will return a string of the value if there is only one header, or if there is more than one matching header, will return an array of values in order that they appear in the header ordered from top to bottom.

Example:

h = Header.new
h.fields = ['To: [email protected]', 'X-Mail-SPAM: 15', 'X-Mail-SPAM: 20']
h['To']          #=> '[email protected]'
h['X-Mail-SPAM'] #=> ['15', '20']



129
130
131
132
133
134
135
136
137
138
139
140
 
# File 'lib/mail/header.rb', line 129

def [](name)
  name = dasherize(name).downcase
  selected = select_field_for(name)
  case
  when selected.length > 1
    selected.map { |f| f }
  when !selected.blank?
    selected.first
  else
    nil
  end
end

#[]=(name, value) ⇒ Object

Sets the FIRST matching field in the header to passed value, or deletes the FIRST field matched from the header if passed nil

Example:

h = Header.new
h.fields = ['To: [email protected]', 'X-Mail-SPAM: 15', 'X-Mail-SPAM: 20']
h['To'] = '[email protected]'
h['To']    #=> '[email protected]'
h['X-Mail-SPAM'] = '10000'
h['X-Mail-SPAM'] # => ['15', '20', '10000']
h['X-Mail-SPAM'] = nil
h['X-Mail-SPAM'] # => nil



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
 
# File 'lib/mail/header.rb', line 155

def []=(name, value)
  name = dasherize(name)
  fn = name.downcase
  selected = select_field_for(fn)
  
  case
  # User wants to delete the field
  when !selected.blank? && value == nil
    fields.delete_if { |f| selected.include?(f) }
    
  # User wants to change the field
  when !selected.blank? && limited_field?(fn)
    selected.first.update(fn, value)
    
  # User wants to create the field
  else
    # Need to insert in correct order for trace fields
    self.fields << Field.new(name.to_s, value, charset)
  end
  if dasherize(fn) == "content-type"
    # Update charset if specified in Content-Type
    params = self[:content_type].parameters rescue nil
    @charset = params && params[:charset]
  end
end

#charset ⇒ Object 



181
182
183
 
# File 'lib/mail/header.rb', line 181

def charset
  @charset
end

#charset=(val) ⇒ Object 



185
186
187
188
189
190
191
 
# File 'lib/mail/header.rb', line 185

def charset=(val)
  params = self[:content_type].parameters rescue nil
  if params
    params[:charset] = val
  end
  @charset = val
end

#decoded ⇒ Object

Raises:

  • (NoMethodError) 


211
212
213
 
# File 'lib/mail/header.rb', line 211

def decoded
  raise NoMethodError, 'Can not decode an entire header as there could be character set conflicts, try calling #decoded on the various fields.'
end

#encoded ⇒ Object 



199
200
201
202
203
204
205
 
# File 'lib/mail/header.rb', line 199

def encoded
  buffer = ''
  fields.each do |field|
    buffer << field.encoded
  end
  buffer
end

#errors ⇒ Object 



104
105
106
 
# File 'lib/mail/header.rb', line 104

def errors
  @errors
end

#field_summary ⇒ Object 



215
216
217
 
# File 'lib/mail/header.rb', line 215

def field_summary
  fields.map { |f| "<#{f.name}: #{f.value}>" }.join(", ")
end

#fields ⇒ Object

Returns an array of all the fields in the header in order that they were read in.



65
66
67
 
# File 'lib/mail/header.rb', line 65

def fields
  @fields ||= FieldList.new
end

#fields=(unfolded_fields) ⇒ Object

3.6. Field definitions

It is important to note that the header fields are not guaranteed to
be in a particular order.  They may appear in any order, and they
have been known to be reordered occasionally when transported over
the Internet.  However, for the purposes of this standard, header
fields SHOULD NOT be reordered when a message is transported or
transformed.  More importantly, the trace header fields and resent
header fields MUST NOT be reordered, and SHOULD be kept in blocks
prepended to the message.  See sections 3.6.6 and 3.6.7 for more
information.

Populates the fields container with Field objects in the order it receives them in.

Acceps an array of field string values, for example:

h = Header.new
h.fields = ['From: [email protected]', 'To: [email protected]']



88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
 
# File 'lib/mail/header.rb', line 88

def fields=(unfolded_fields)
  @fields = Mail::FieldList.new
  warn "Warning: more than #{self.class.maximum_amount} header fields only using the first #{self.class.maximum_amount}" if unfolded_fields.length > self.class.maximum_amount
  unfolded_fields[0..(self.class.maximum_amount-1)].each do |field|

    field = Field.new(field, nil, charset)
    field.errors.each { |error| self.errors << error }
    if limited_field?(field.name) && (selected = select_field_for(field.name)) && selected.any? 
      selected.first.update(field.name, field.value)
    else
      @fields << field
    end
  end

end

#has_content_id? ⇒ Boolean

Returns true if the header has a Content-ID defined (empty or not)

Returns:

  • (Boolean) 


225
226
227
 
# File 'lib/mail/header.rb', line 225

def has_content_id?
  !fields.select { |f| f.responsible_for?('Content-ID') }.empty?
end

#has_date? ⇒ Boolean

Returns true if the header has a Date defined (empty or not)

Returns:

  • (Boolean) 


230
231
232
 
# File 'lib/mail/header.rb', line 230

def has_date?
  !fields.select { |f| f.responsible_for?('Date') }.empty?
end

#has_message_id? ⇒ Boolean

Returns true if the header has a Message-ID defined (empty or not)

Returns:

  • (Boolean) 


220
221
222
 
# File 'lib/mail/header.rb', line 220

def has_message_id?
  !fields.select { |f| f.responsible_for?('Message-ID') }.empty?
end

#has_mime_version? ⇒ Boolean

Returns true if the header has a MIME version defined (empty or not)

Returns:

  • (Boolean) 


235
236
237
 
# File 'lib/mail/header.rb', line 235

def has_mime_version?
  !fields.select { |f| f.responsible_for?('Mime-Version') }.empty?
end

#raw_source ⇒ Object

The preserved raw source of the header as you passed it in, untouched for your Regexing glory.



59
60
61
 
# File 'lib/mail/header.rb', line 59

def raw_source
  @raw_source
end

#to_s ⇒ Object 



207
208
209
 
# File 'lib/mail/header.rb', line 207

def to_s
  encoded
end