Class: Net::IMAP::BodyTypeAttachment

Inherits:
Struct
  • Object
show all
Defined in:
lib/net/imap/response_data.rb

Overview

BodyTypeAttachment is not used and will be removed in an upcoming release.

Bug Analysis

IMAP body structures are parenthesized lists and assign their fields positionally, so missing fields change the intepretation of all following fields. Additionally, different body types have a different number of required fields, followed by optional “extension” fields.

BodyTypeAttachment was previously returned when a “message/rfc822” part, which should be sent as body-type-msg with ten required fields, was actually sent as a body-type-basic with seven required fields.

basic => type, subtype, param, id, desc, enc, octets, md5=nil,  dsp=nil, lang=nil, loc=nil, *ext
msg   => type, subtype, param, id, desc, enc, octets, envelope, body,    lines,    md5=nil, ...

Normally, envelope and md5 are incompatible, but Net::IMAP leniently allowed buggy servers to send NIL for envelope. As a result, when a server sent a message/rfc822 part with NIL for md5 and a non-NIL dsp, Net::IMAP mis-interpreted the Content-Disposition as if it were a strange body type. In all reported cases, the Content-Disposition was “attachment”, so BodyTypeAttachment was created as the workaround.

Current behavior

When interpreted strictly, envelope and md5 are incompatible. So the current parsing algorithm peeks ahead after it has recieved the seventh body field. If the next token is not the start of an envelope, we assume the server has incorrectly sent us a body-type-basic and return BodyTypeBasic. As a result, what was previously BodyTypeMessage#body => BodyTypeAttachment is now BodyTypeBasic#disposition => ContentDisposition.

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#_unused_ ⇒ Object

Returns the value of attribute unused

Returns:

  • (Object) —

    the current value of unused



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# File 'lib/net/imap/response_data.rb', line 1018

def _unused_
  @_unused_
end

#dsp_type ⇒ Object

Returns the value of attribute dsp_type

Returns:

  • (Object) —

    the current value of dsp_type



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# File 'lib/net/imap/response_data.rb', line 1018

def dsp_type
  @dsp_type
end

#param ⇒ Object

Returns the value of attribute param

Returns:

  • (Object) —

    the current value of param



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# File 'lib/net/imap/response_data.rb', line 1018

def param
  @param
end

Instance Method Details

#media_type ⇒ Object

*invalid for BodyTypeAttachment*



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# File 'lib/net/imap/response_data.rb', line 1020

def media_type
  warn(<<~WARN, uplevel: 1)
    BodyTypeAttachment#media_type is obsolete.  Use dsp_type instead.
  WARN
  dsp_type
end

#multipart? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/net/imap/response_data.rb', line 1048

def multipart?
  return false
end

#subtype ⇒ Object

*invalid for BodyTypeAttachment*



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# File 'lib/net/imap/response_data.rb', line 1028

def subtype
  warn("BodyTypeAttachment#subtype is obsolete.\n", uplevel: 1)
  nil
end