Class: Mime

Inherits:
Object
  • Object
show all
Defined in:
lib/mime.rb

Overview

Introduction

A basic mime class for really basic and probably non-standard parsing and construction of MIME messages.

Intended for two main purposes in this project:

  1. As the container that is used to build up the message for eventual serialization as an eml.

  2. For assistance in parsing the transport_message_headers provided in .msg files, which are then kept through to the final eml.

TODO

  • Better streaming support, rather than an all-in-string approach.

  • Add OrderedHash optionally, to not lose ordering in headers.

  • A fair bit remains to be done for this class, its fairly immature. But generally I’d like to see it be more generally useful.

  • All sorts of correctness issues, encoding particular.

  • Duplication of work in net/http.rb’s HTTPHeader? Don’t know if the overlap is sufficient. I don’t want to lower case things, just for starters.

  • Mime was the original place I wrote #to_tree, intended as a quick debug hack.

Constant Summary collapse

Hash = 
begin
	require 'orderedhash'
	OrderedHash
rescue LoadError
	Hash
end

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(str, ignore_body = false) ⇒ Mime

Create a Mime object using str as an initial serialization, which must contain headers and a body (even if empty). Needs work.



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# File 'lib/mime.rb', line 36

def initialize str, ignore_body=false
	headers, @body = $~[1..-1] if str[/(.*?\r?\n)(?:\r?\n(.*))?\Z/m]

	@headers = Hash.new { |hash, key| hash[key] = [] }
	@body ||= ''
	headers.to_s.scan(/^\S+:\s*.*(?:\n\t.*)*/).each do |header|
		@headers[header[/(\S+):/, 1]] << header[/\S+:\s*(.*)/m, 1].gsub(/\s+/m, ' ').strip # this is kind of wrong
	end

	# don't have to have content type i suppose
	@content_type, attrs = nil, {}
	if content_type = @headers['Content-Type'][0]
		@content_type, attrs = Mime.split_header content_type
	end

	return if ignore_body

	if multipart?
		if body.empty?
			@preamble = ''
			@epilogue = ''
			@parts = []
		else
			# we need to split the message at the boundary
			boundary = attrs['boundary'] or raise "no boundary for multipart message"

			# splitting the body:
			parts = body.split(/--#{Regexp.quote boundary}/m)
			unless parts[-1] =~ /^--/; warn "bad multipart boundary (missing trailing --)"
			else parts[-1][0..1] = ''
			end
			parts.each_with_index do |part, i|
				part =~ /^(\r?\n)?(.*?)(\r?\n)?\Z/m
				part.replace $2
				warn "bad multipart boundary" if (1...parts.length-1) === i and !($1 && $3)
			end
			@preamble = parts.shift
			@epilogue = parts.pop
			@parts = parts.map { |part| Mime.new part }
		end
	end
end

Instance Attribute Details

#body ⇒ Object (readonly)

Returns the value of attribute body.



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# File 'lib/mime.rb', line 32

def body
  @body
end

#content_type ⇒ Object (readonly)

Returns the value of attribute content_type.



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# File 'lib/mime.rb', line 32

def content_type
  @content_type
end

#epilogue ⇒ Object (readonly)

Returns the value of attribute epilogue.



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# File 'lib/mime.rb', line 32

def epilogue
  @epilogue
end

#headers ⇒ Object (readonly)

Returns the value of attribute headers.



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# File 'lib/mime.rb', line 32

def headers
  @headers
end

#parts ⇒ Object (readonly)

Returns the value of attribute parts.



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# File 'lib/mime.rb', line 32

def parts
  @parts
end

#preamble ⇒ Object (readonly)

Returns the value of attribute preamble.



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# File 'lib/mime.rb', line 32

def preamble
  @preamble
end

Class Method Details

.make_boundary(i, extra_obj = Mime) ⇒ Object

i is some value that should be unique for all multipart boundaries for a given message



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# File 'lib/mime.rb', line 139

def self.make_boundary i, extra_obj = Mime
	"----_=_NextPart_#{'%03d' % i}_#{'%08x' % extra_obj.object_id}.#{'%08x' % Time.now}"
end

.split_header(header) ⇒ Object 



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# File 'lib/mime.rb', line 121

def self.split_header header
	# FIXME: haven't read standard. not sure what its supposed to do with " in the name, or if other
	# escapes are allowed. can't test on windows as " isn't allowed anyway. can be fixed with more
	# accurate parser later.
	# maybe move to some sort of Header class. but not all headers should be of it i suppose.
	# at least add a join_header then, taking name and {}. for use in Mime#to_s (for boundary
	# rewrite), and Attachment#to_mime, among others...
	attrs = {}
	header.scan(/;\s*([^\s=]+)\s*=\s*("[^"]*"|[^\s;]*)\s*/m).each do |key, value|
		if attrs[key]; warn "ignoring duplicate header attribute #{key.inspect}"
		else attrs[key] = value[/^"/] ? value[1..-2] : value
		end
	end

	[header[/^[^;]+/].strip, attrs]
end

Instance Method Details

#inspect ⇒ Object 



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# File 'lib/mime.rb', line 83

def inspect
	# add some extra here.
	"#<Mime content_type=#{@content_type.inspect}>"
end

#multipart? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/mime.rb', line 79

def multipart?
	@content_type && @content_type =~ /^multipart/ ? true : false
end

#to_s(opts = {}) ⇒ Object 



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# File 'lib/mime.rb', line 103

def to_s opts={}
	opts = {:boundary_counter => 0}.merge opts
	if multipart?
		boundary = Mime.make_boundary opts[:boundary_counter] += 1, self
		@body = [preamble, parts.map { |part| "\r\n" + part.to_s(opts) + "\r\n" }, "--\r\n" + epilogue].
			flatten.join("\r\n--" + boundary)
		content_type, attrs = Mime.split_header @headers['Content-Type'][0]
		attrs['boundary'] = boundary
		@headers['Content-Type'] = [([content_type] + attrs.map { |key, val| %{#{key}="#{val}"} }).join('; ')]
	end

	str = ''
	@headers.each do |key, vals|
		vals.each { |val| str << "#{key}: #{val}\r\n" }
	end
	str << "\r\n" + @body
end

#to_tree ⇒ Object 



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# File 'lib/mime.rb', line 88

def to_tree
	if multipart?
		str = "- #{inspect}\n"
		parts.each_with_index do |part, i|
			last = i == parts.length - 1
			part.to_tree.split(/\n/).each_with_index do |line, j|
				str << "  #{last ? (j == 0 ? "\\" : ' ') : '|'}" + line + "\n"
			end
		end
		str
	else
		"- #{inspect}\n"
	end
end