This file documents SEMI, a MIME user interface for GNU Emacs.
SEMI is a package for GNU Emacs to provide features related with MIME user interface. SEMI-EPG is a variant of SEMI, which features supports to EasyPG and latest Emacs.
SEMI provides two user interfaces: MIME-View and MIME-Edit.
MIME-View is a kernel of user interface to display or operate MIME messages, STD 11 messages or “localized RFC 822” messages.
MIME-Edit is a user interface to compose MIME messages.
Each MUA can use powerful MIME features to combine these features.
MIME-View is a MIME viewer for wide use that runs on GNU Emacs.
MIME-View is the kernel of the user interface for browsing MIME messages. You can start some presentation-method which is a program for creating some representation, or some acting-method which is a program for processing the entity. Then you can deal with a variety of entities.
The representation form of the internet messages in electric letters or in net news is based on STD 11. The STD 11 message body is a plain text which consists of lines as its only structure, and the character code is fixed as us-ascii. Actually, there are “localized STD 11” messages that use some character code in their linguistic range instead of using us-ascii. Even in that case, the character code in the message is single. Therefore, Message User Agents have considered (byte row) = (us-ascii string), or (byte row) = (string in the character code in the linguistic range).
Although, the MIME message has the tree structure in entity unit. And one message can contain multiple character codes. The content of an entity can be not only a letter or an image that can be displayed simply, but also can be a voice or an animation that are played for some time interval, a data for some specific application, a source code of some program, or an external reference that consists of the usage of ftp or mail service, or some URL. Therefore the simple extension of STD 11 user interface, which only consider displaying the message, cannot treat all of the MIME functionalities. Then it is not sufficient to decode message along its MIME type, but it is also required to consider a playback processing through some dialogue with the user. The format of MIME messages is designed to easily be passed to automatic processing. But some contents in the MIME message should not be passed to automatic processing for security reasons. So it should be designed to ask user in such cases. After all, in order to deal with MIME message, it is required to distinguish the representation for information exchange which is written in STD 11 or MIME construction, and its result after some interpretation which is a display screen or a playback process. It is also needed to converse with user for playback processing.
Therefore, MIME-View uses two buffers for one document, one is the mime-raw-buffer that stores the representation for information exchange, and the other is the mime-preview-buffer that stores the representation for displaying.
MIME-View provides a mode in the mime-preview-buffer for reading MIME message, which is called as mime-view-mode. User can manipulate each entity there.
mime-view-mode displays information about each entity as
[entity-button] (header) (body) (separator)
You can change their design or inhibit showing some of them, according to some condition.
See following example
From: morioka@jaist.ac.jp (MORIOKA Tomohiko)
Subject: Re: question?
Newsgroups: zxr.message.mime
Date: 22 Oct 93 11:02:44
Mime-Version: 1.0
Organization: Japan Advanced Institute of Science and Technology,
Ishikawa, Japan
[1 (text/plain)]
How to compose MIME message in MIME-Edit mode.
C-c C-x ? shows its help.
C-c C-x C-t insert a text message.
C-c C-x TAB insert a (binary) file.
C-c C-x C-e insert a reference to external body.
C-c C-x C-v insert a voice message.
C-c C-x C-y insert a mail or news message.
C-c C-x RET insert a mail message.
C-c C-x C-s insert a signature file at end.
C-c C-x t insert a new MIME tag.
C-c C-m C-a enclose as multipart/alternative.
C-c C-m C-p enclose as multipart/parallel.
C-c C-m C-m enclose as multipart/mixed.
C-c C-m C-d enclose as multipart/digest.
C-c C-m C-s enclose as PGP signed.
C-c C-m C-e enclose as PGP encrypted.
C-c C-x C-k insert PGP public key.
C-c C-x p preview editing MIME message.
...
therefore, you should type C-c C-x C-i and specify the binary file
which you want to insert.
You should select Base64 as MIME encoding for binary file.
[2 (image/gif)]
[3 (text/plain)]
Like above, you can compose the message with image.
==================== Take A Cup Of Russian Tea ======================
========= ** Not With Jam Nor Marmalade But With Honey ** ==========
========= MORIOKA TOMOHIKO ==========
============== Internet E-mail: <morioka@jaist.ac.jp> ==============
entity-button is a tag on the top of the entity which shows brief information of the part.
Normally, it appears as
[1.3 test (text/plain)]
The number on the head describes the place of the entity in the message (like the section number) and it is called as entity-number.
The string in the next describes its title. This information is taken from
If none of them are specified, displays a blank.
The 3rd item in the parenthesis describes media-type/subtype of
the entity. If it is is not MIME entity, it displays nil.
This entity-button plays a role like icon that symbolically shows the content of the entity. For example, push v on
[2 (image/gif)]
shows up the image contained there.
If the mouse operation is possible, you can display the image by pushing 2nd button (the middle button for 3 button mouse) too.
entity-header is the header of the entity. (Don’t blame me as “You say nothing more than as it is”, It is no more than that.)
entity-body is the content of the part.
Sophistication does not seem enough here also, but it is really such a thing.
Though, it actually be twisted a little.
The text entity is passed to code conversion according to its charset, and the image entity should be converted on XEmacs.
Details will be described later.
mime-preview-buffer posesses following functionalities.
go back to upper part (in the first part of the message, go back to the Summary mode (*1))
go to previous part
go to previous part
go to next part
go to next part
scroll up
scroll down
scroll down
go to next line
go to previous line
play current part (*2)
extract file from current part (*2)
print current part (*2)
start the mouse button in preview-buffer
on content-button, play current part (*2)
on URL-button, start WWW browser
[Notice]
(*1) Do not go back to Summary mode unless appropriately configured for mime-view in the MUA.
(*2) actual behavior depends on the associated method
MIME-Edit is a general MIME composer for GNU Emacs.
mime-edit-mode is a minor mode to compose MIME message. In this mode, tag represents various kinds of data, so you can edit multi part message consists of various kinds of data, such as text, image, audio, etc.
There are 2 kinds of tags:
single-part tag represents single part, this form is following:
--[[TYPE/SUBTYPE;PARAMETERS
OPTIONAL-FIELDS][ENCODING]]
TYPE/SUBTYPE and PARAMETERS indicates type/subtype and parameters of Content-Type (Content-Type in FLIM Manual) field. TYPE/SUBTYPE is required, PARAMETERS is optional.
ENCODING indicates Content-Transfer-Encoding (Content-Transfer-Encoding in FLIM Manual) field. It is optional too.
OPTIONAL-FIELDS is to represent another fields except Content-Type field and Content-Transfer-Encoding field.
multi-part tags represent multi part. They consist of a pair of multi-part beginning tag and multi-part ending tag.
multi-part beginning tag’s form is following:
--<<TYPE>>-{
multi-part ending tag’s form is following:
--}-<<TYPE>>
A region from multi-part beginning tag to multi-part ending tag is called as enclosure.
Operations to make single-part are following:
Insert single-part tag indicates text part.
Insert file as a MIME attachment. If C-u is followed by it, it asks media-type, subtype or encoding even if their default values are specified. (cf. How to detect tag for inserted file)
Insert external part.
Record audio input until C-g is pressed, and insert as a audio part. (It requires /dev/audio in default.)
Insert current (mail or news) message. (It is MUA depended.)
Insert mail message. (It is MUA depended.)
Insert signature.
Insert PGP (PGP) public key. (It requires Mailcrypt package.)
Insert any single-part tag.
Operations to make enclosure are following:
Enclose specified region as multipart/alternative.
Enclose specified region as multipart/parallel.
Enclose specified region as multipart/mixed.
Enclose specified region as multipart/digest.
Digital-sign to specified region. (cf. PGP)
Encrypt to specified region. (cf. PGP)
avoid to encode tags in specified region. In other words, tags is interpreted as such string. (In current version, it may be incomplete. Maybe PGP-signature does not work for this enclosure.)
There are another operations in mime-edit-mode.
Send current editing message.
Preview current editing message. (cf. MIME message viewing)
Exit mime-edit-mode without sending.
Set current editing message to enable automatic splitting or not. Form of automatic split messages is message/partial.
Set 7bit (7bit in FLIM Manual) to transfer level (transfer level).
Set 8bit (8bit in FLIM Manual) to transfer level (transfer level).
Set current editing message to digital-sign or not. (cf. PGP)
Set current editing message to encrypt or not. (cf. PGP)
Display help message.
When C-c C-x C-i (mime-edit-insert-file) is pressed, tag
parameters for inserted file, such as media-type or encoding, are
detected by variable mime-file-types.
When C-u is followed by it or parameter is not found from the variable, it asks from user. (When C-u is followed by it, detected value is used as default value)
If you want to change default value for file names, please change
variable mime-file-types.
Specification of default value of tag for file name of inserted file.
It is a list of following list:
(FILE_PAT TYPE SUBTYPE PARAMS ENCODING DISPOSITION_TYPE DISPOSITION_PARAMS)
Each element of the list is following:
regular expression of file name
primary-type of media-type
subtype of media-type
parameters of Content-Type field
Content-Transfer-Encoding
disposition-type
parameters of Content-Disposition field
Example: Specify application/rtf as default media type for *.rtf
(eval-after-load
"mime-edit"
'(set-alist 'mime-file-types
"\\.rtf$"
'("application" "rtf" nil nil
"attachment" (("filename" . file)))
))
Each content inserted in a message is represented by 7bit (7bit in FLIM Manual), 8bit (8bit in FLIM Manual) or binary (binary in FLIM Manual).
If a message is translated by 7bit-through MTA (MTA in FLIM Manual), there is no need to encode 7bit data, but 8bit and binary data must be encoded to 7bit data.
Similarly, if a message is translated by 8bit-through MTA, there is no need to encode 7bit or 8bit data, but binary data must be encoded to 7bit or 8bit data.
[Memo]
EBCDIC MTA breaks 7bit data, so in this case, 7bit data must be encoded by base64. But I don’t know EBCDIC. (^_^;
Similarly, I wish ASCII-printable only MTA and code-conversion MTA disappeared. (^_^;
Maybe there are binary-through MTA, but I think it is not major.
transfer level represents how range data are
available. mime-edit has a variable mime-transfer-level
to represent transfer level.
transfer level.
If transfer level of a data is over it, a data is encoded to 7bit.
Currently, 7 or 8 is available. Default value is 7.
In extension plan, EBCDIC will be 5, ASCII printable only will be 6, binary will be 9. But it will not be implemented.
[Memo]
transfer level is only for body, not for message header (entity-header). MIME extends RFC 822 (RFC 822 in FLIM Manual) to use 8bit data in body, but it requires to use us-ascii (us-ascii in FLIM Manual) in header.
Split large message if it is non-nil.
Default maximum lines of a message.
Alist of major-mode vs maximum lines of a message.
If it is not specified for a major-mode,
mime-edit-message-default-max-lines is used.
Regular expression to match field-name to be ignored when split sending.
mime-edit provides PGP encryption, signature and inserting public-key features based on PGP/MIME (RFC 3156) by using EasyPG.
When non-nil, ask the user about the current operation more verbosely.
A list of your own key ID which will be preferredly used to sign a message.
When non-nil, add sender’s key ID to recipient list when encryption. When nil, sender can’t decrypt encrypted content in general.
A list of keys’s validities which are used for neither signing nor encrypting.
Face used for content-button or URL-button of MIME-Preview buffer.
Face used for MIME-preview buffer mouse highlighting.
Function to browse URL.
Add condition to database specified by target-type.
target-type must be preview or action.
If optional argument mode is strict or nil
(omitted), condition is added strictly.
If optional argument mode is with-default, condition
is added with default rule.
If optional argument file is specified, it is loaded when condition is activate.
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