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<TITLE>Sylpheed User's Manual: Handling MIME types</TITLE>
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<H2><A NAME="s14">14. Handling MIME types</A></H2>
<H2><A NAME="ss14.1">14.1 How Sylpheed checks for Mime types</A>
</H2>
<P>When attaching a file to a message (composing a new message), the
MIME type of the attached file is choosen based on the file extension
from the mapping list defined in the <I>mime.types</I> file(s).
Sylpheed defines its MIME type mapping table by loading the
system wide MIME types file, then the user file.
The systeme file is <I>SYSCONFDIR/mime.types</I> (SYSCONFDIR can
be defined a compile time), or if it does not exist, <I>/etc/mime.types</I>.
The user file is <I>$HOME/.sylpheed/mime.types</I>.
<P>A <I>mime.types</I> file consist of one MIME type definition per line,
each definition line starting with the name of the MIME type, followed by
a space separated list of the corresponding file extensions.
The file can contain empty lines, and comments start with the <CODE>#</CODE>
character and close at line's end.
<P>Following is a typical <I>mime.types</I> file (an extract of mine):
<P>
<PRE>
# This file controls what Internet media types are sent to the client for
# given file extension(s). Sending the correct media type to the client
# is important so they know how to handle the content of the file.
# The Internet media type registry is at
# <ftp://ftp.iana.org/in-notes/iana/assignments/media-types/>.
# MIME type Extension
application/mac-binhex40 hqx
application/mac-compactpro cpt
application/msword doc
application/pdf pdf
application/postscript ai eps ps
application/rtf rtf
application/x-bcpio bcpio
application/x-bzip2 bz2
application/x-csh csh
application/x-gtar gtar
application/x-gzip gz tgz
application/x-kword kwd kwt
application/x-kspread ksp
application/x-kpresenter kpr kpt
application/x-kchart chrt
application/x-latex latex
application/x-sh sh
application/x-shar shar
application/x-shockwave-flash swf
application/x-tar tar
application/x-tcl tcl
application/x-tex tex
application/x-texinfo texinfo texi
application/x-troff t tr roff
application/x-troff-man man
application/zip zip
audio/mpeg mpga mp2 mp3
audio/x-aiff aif aiff aifc
audio/x-wav wav
image/gif gif
image/ief ief
image/jpeg jpeg jpg jpe
image/png png
image/tiff tiff tif
text/plain asc txt
text/rtf rtf
text/sgml sgml sgm
text/xml xml
video/mpeg mpeg mpg mpe
video/x-msvideo avi
text/html html htm
</PRE>
<P>
<P>If the file can be found or has the wrong format, Sylpheed will assume
the default MIME type for all the attachments: <I>application/octet-stream</I>.
In such a case, the recipients mail client may not know what application
to use to view the attachment.
<P>
<H2><A NAME="ss14.2">14.2 How Sylpheed handles attachments (reception)</A>
</H2>
<P>When opening an attachment (select the attachment, right click and select
<I>Open</I>) Sylpheed uses one of the following methods to determine
the application to launch:
<P>
<UL>
<LI>The attachment is an image: the application is the one defined by the
<I>mime_image_viewer</I> variable of the common preferences configuration
file (<I>$HOME/.sylpheed/sylpheedrc</I>). If no application is defined, or
if the format of the definition is not valid, the default application
command is <I>display</I> (ImageMagick viewer).</LI>
<LI>The attachment is a sound file: the application is the one defined by the
<I>mime_audio_player</I> variable of the common preferences configuration
file (<I>$HOME/.sylpheed/sylpheedrc</I>). If no application is defined, or
if the format of the definition is not valid, the default application
command is <I>play</I>.</LI>
<LI>The attachment is a HTML file: the application is the one defined by the
<I>uri_cmd</I> variable of the common preferences configuration
file (<I>$HOME/.sylpheed/sylpheedrc</I>). This can also be changed in the
<I>Common preferences</I>, by changing the <I>Web browser</I> defined
in the <I>Other</I> tab.</LI>
<LI>Any other attachment type: Sylpheed relies on <I>metamail</I> to use
the correct application (Sylpheed starts <I>metamail</I> giving it
the attachment file and the MIME type taken from the mail).</LI>
</UL>
<P>
<P>The binding of the applications to each MIME type is defined in the
<I>mailcap</I> file. The systeme wide file is <I>/etc/mailcap</I>,
while the user file is <I>$HOME/.mailcap</I>.
<P>
<P>In the mailcap file, there is one definition per line, big lines
can be broken by escaping the newline with a <I>\</I> character,
the first element of the line is the MIME type, then a semi-colon,
(<I>;</I>), and finally the application to launch.
The application part (right side of the semi-colon) can contain several
shell commands separated by an escaped semi-colon (<I>\;</I>) and
the <I>%s</I> string is replaced by the name of the file when
launching the command.
<P>
<P>Following is a typical <I>mailcap</I> file (an extract of mine):
<P>
<PRE>
image/*; ee %s
video/mpeg; gtv %s
video/*; xanim %s
application/pdf; xpdf %s
text/html; dillo %s
</PRE>
<P>
<P>
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