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10.1 Message Decoding
mime-analyze
message
entity
disposition
10.2 Exceptions
mime-error
unexpected-termination
missing-multipart-boundary-parameter
malformed-multipart-entity
empty-mechanism
empty-type
empty-subtype
empty-disposition-type
10.3 MIME Unit
mime@
10.4 MIME Signature
mime^

10 MIME: Decoding Internet Data

The net/mime library provides utilities for parsing and creating MIME encodings as described in RFC 2045 through RFC 2049.
The library was written by Francisco Solsona.

10.1 Message Decoding

(mime-analyze message-in part?)  message?
  message-in : (or/c bytes? input-port)
  part? : any/c
Parses message-in and returns the parsed result as a message instance.

(struct message (version entity fields))
  version : real?
  entity : entity
  fields : (listof string?)
A decoded MIME message. The version is 1.0 by default. The entity field represents the message data. The fields field contains one string for each field in the message header.

(struct entity (type
    subtype
    charset
    encoding
    disposition
    params
    id
    description
    other
    fields
    parts
    body))
  type : symbol?
  subtype : symbol?
  charset : symbol?
  encoding : symbol?
  disposition : disposition?
  params : (listof (cons/c symbol? string?))
  id : string?
  description : string?
  other : (listof string?)
  fields : (listof string?)
  parts : (listof message?)
  body : (output-port? . -> . void?)
Represents the content of a message or a sub-part.

Standard values for the type field include 'text, 'image, 'audio, 'video, 'application, 'message, and 'multipart.

Standard values for the subtype field depend on the type field, and include the following:

'text

 

'plain

 

[RFC1521, NSB]

 

 

'richtext

 

[RFC1521, NSB]

 

 

'tab-separated-values

 

[Lindner]

'multipart

 

'mixed

 

[RFC1521, NSB]

 

 

'alternative

 

[RFC1521, NSB]

 

 

'digest

 

[RFC1521, NSB]

 

 

'parallel

 

[RFC1521, NSB]

 

 

'appledouble

 

[MacMime, Faltstrom]

 

 

'header-set

 

[Crocker]

'message

 

'rfc822

 

[RFC1521, NSB]

 

 

'partial

 

[RFC1521, NSB]

 

 

'external-body

 

[RFC1521, NSB]

 

 

'news

 

[RFC 1036, Spencer]

'application

 

'octet-stream

 

[RFC1521, NSB]

 

 

'postscript

 

[RFC1521, NSB]

 

 

'oda

 

[RFC1521, NSB]

 

 

'atomicmail

 

[atomicmail, NSB]

 

 

'andrew-inset

 

[andrew-inset, NSB]

 

 

'slate

 

[slate, Crowley]

 

 

'wita

 

[Wang Info Transfer, Campbell]

 

 

'dec-dx

 

[Digital Doc Trans, Campbell]

 

 

'dca-rft

 

[IBM Doc Content Arch, Campbell]

 

 

'activemessage

 

[Shapiro]

 

 

'rtf

 

[Lindner]

 

 

'applefile

 

[MacMime, Faltstrom]

 

 

'mac-binhex40

 

[MacMime, Faltstrom]

 

 

'news-message-id

 

[RFC1036, Spencer]

 

 

'news-transmission

 

[RFC1036, Spencer]

 

 

'wordperfect5.1

 

[Lindner]

 

 

'pdf

 

[Lindner]

 

 

'zip

 

[Lindner]

 

 

'macwriteii

 

[Lindner]

 

 

'msword

 

[Lindner]

 

 

'remote-printing

 

[RFC1486,MTR]

'image

 

'jpeg

 

[RFC1521, NSB]

 

 

'gif

 

[RFC1521, NSB]

 

 

'ief

 

[RFC1314]

 

 

'tiff

 

[MTR]

'audio

 

'basic

 

[RFC1521, NSB]

'video

 

'mpeg

 

[RFC1521, NSB]

 

 

'quicktime

 

[Lindner]

Standard values for the charset field include 'us-ascii, which is the default.

Standard values for the encoding field are '7bit, '8bit, 'binary, 'quoted-printable, and 'base64. The default is '7bit.

The params field contains a list of parameters from other MIME headers.

The id field is taken from the "Content-Id" header field.

The description field is taken from the "Content-description" header field.

The other field contains additional (non-standard) field headers whose field names start with "Content-".

The fields field contains additional field headers whose field names do not start with "Content-".

The parts contains sub-parts from multipart MIME messages. This list is non-empty only when type is 'multipart or 'message.

The body field represents the body as a function that consumes an output out and writes the decoded message to the port. No bytes are written if type is 'multipart or 'message. All of the standard values of encoding are supported. The procedure only works once (since the encoded body is pulled from a stream).

(struct disposition (type
    filename
    creation
    modification
    read
    size
    params))
  type : symbol?
  filename : (or/c string? false/c)
  creation : (or/c string? false/c)
  modification : (or/c string? false/c)
  read : (or/c string? false/c)
  size : (or/c exact-nonnegative-integer? false/c)
  params : (listof (cons/c symbol? string?))
Represents a "Content-Disposition" header as defined in RFC 2183.

Standard values for the type field include 'inline and 'attachment.

The filename field is drawn from the "filename" parameter of the "Content-Disposition" header, if included in the message.

The creation, modification, and read fields represent file timestamps as drawn from the "creation-date", "modification-date", and "read-date" attributes of the "Content-Disposition" header, if included in the message.

The size field is drawn from the "size" parameter of the "Content-Disposition" header, if included in the message.

The params field stores any additional attribute bindings of the "Content-Disposition" header, if included in the message.

10.2 Exceptions

(struct mime-error ())
The supertype of all MIME exceptions.

(struct (unexpected-termination mime-error) (msg))
  msg : string?
Raised when an end-of-file is reached while parsing the headers of a MIME entity. It usually means that the message does not conform to RFC 2045 and friends.

Raised when a multipart type is specified, but no "Boundary" parameter is given or an end-of-file is encountered before the boundary.

(struct (malformed-multipart-entity mime-error) (msg))
  msg : string?
Similar to unexpected-termination, but used only while scanning parts of a multipart message.

Raised when no transport encoding mechanism was provided with the "Content-Transfer-Encoding" field.

(struct (empty-type mime-error) ())
Raised when no type is specified for "Content-Type", or when the specification is incorrectly formatted.

Raised when no sub-type is specified for "Content-Type", or when the specification is incorrectly formatted.

Raised when type specified for the "Content-Disposition" field, or when the specification is incorrectly formatted.

10.3 MIME Unit

 (require net/mime-unit)

mime@ : unit?
Imports nothing, exports mime^.

10.4 MIME Signature

 (require net/mime-sig)

mime^ : signature

Includes everything exported by the net/mime module.