Package: debian-policy Version: 3.9.6.0 Dear developers,
To reduce clutter in the BTS log, I am opening a new bug for the second half of the proposal "Document media type declarations" by Charles Plessy in #707851, since I did not find specific objections registered about it. I join the patch. There is one undefined reference to "desktop entries" due to the cut that I will sort out before doing a release. Please check and second it again. Sorry for the delay and duplication, and thanks to Charles for having drafted it. Cheers, -- Bill. <ballo...@debian.org> Imagine a large red swirl here. diff --git a/policy.sgml b/policy.sgml index f4e4281..3ab5912 100644 --- a/policy.sgml +++ b/policy.sgml @@ -8092,42 +8092,109 @@ Reloading <var>description</var> configuration...done. <heading>Multimedia handlers</heading> <p> - MIME (Multipurpose Internet Mail Extensions, RFCs 2045-2049) - is a mechanism for encoding files and data streams and - providing meta-information about them, in particular their - type (e.g. audio or video) and format (e.g. PNG, HTML, - MP3). + Media types (formerly known as MIME types, Multipurpose Internet Mail + Extensions, RFCs 2045-2049) is a mechanism for encoding files and + data streams and providing meta-information about them, in particular + their type and format (e.g. <tt>image/png</tt>, <tt>text/html</tt>, + <tt>audio/ogg</tt>). </p> <p> - Registration of MIME type handlers allows programs like mail + Registration of media type handlers allows programs like mail user agents and web browsers to invoke these handlers to - view, edit or display MIME types they don't support directly. + view, edit or display media types they don't support directly. </p> <p> - Packages which provide programs to view/show/play, compose, edit or - print MIME types should register them as such by placing a file in - <manref name="mailcap" section="5"> format (RFC 1524) in the directory - <file>/usr/lib/mime/packages/</file>. The file name should be the - binary package's name. + There are two overlapping systems to associate media types to programs + which can handle them. The <em>mailcap</em> system is found on a + large number of Unix systems. The <em>FreeDesktop</em> system is + aimed at Desktop environments. In Debian, FreeDesktop entries are + automatically translated in mailcap entries, therefore packages + already using desktop entries should not use the mailcap system + directly. </p> - <p> - The <package>mime-support</package> package provides the - <prgn>update-mime</prgn> program, which integrates these - registrations in the <file>/etc/mailcap</file> file, using dpkg - triggers<footnote> - Creating, modifying or removing a file in - <file>/usr/lib/mime/packages/</file> using maintainer scripts will - not activate the trigger. In that case, it can be done by calling - <tt>dpkg-trigger --no-await /usr/lib/mime/packages</tt> from - the maintainer script after creating, modifying, or removing - the file. - </footnote>. - Packages using this facility <em>should not</em> depend on, - recommend, or suggest <prgn>mime-support</prgn>. - </p> + <sect1 id="media-types-freedesktop"> + <heading>Registration of media type handlers with desktop entries</heading> + + <p> + Packages shipping an application able to view, edit or point to + files of a given media type, or open links with a given URI scheme, + should list it in the <tt>MimeType</tt> key of the application's + <qref id="menus">desktop entry</qref>. For URI schemes, + the relevant MIME types are <tt>x-scheme-handler/*</tt> (e.g. + <tt>x-scheme-handler/https</tt>). + </p> + </sect1> + + <sect1 id="mailcap"> + <heading>Registration of media type handlers with mailcap entries</heading> + + <p> + Packages that are not using desktop entries for registration should + install a file in <manref name="mailcap" section="5"> format (RFC + 1524) in the directory <file>/usr/lib/mime/packages/</file>. The + file name should be the binary package's name. + </p> + + <p> + The <package>mime-support</package> package provides the + <prgn>update-mime</prgn> program, which integrates these + registrations in the <file>/etc/mailcap</file> file, using dpkg + triggers<footnote> + Creating, modifying or removing a file in + <file>/usr/lib/mime/packages/</file> using maintainer scripts will + not activate the trigger. In that case, it can be done by calling + <tt>dpkg-trigger --no-await /usr/lib/mime/packages</tt> from + the maintainer script after creating, modifying, or removing + the file. + </footnote>. + + <p> + Packages installing desktop entries should not install mailcap + entries for the same program, because the + <package>mime-support</package> package already reads desktop + entries. + </p> + + <p> + Packages using these facilities <em>should not</em> depend on, + recommend, or suggest <prgn>mime-support</prgn>. + </p> + </sect1> + + <sect1 id="file-media-type"> + <heading>Providing media types to files</heading> + + <p> + The media type of a file is discovered by inspecting the file's + extension or its <manref name="magic" section="5"> pattern, and + interrogating a database associating them with media types. + </p> + + <p> + To support new associations between media types and files, their + characteristic file extensions and magic patterns should be + registered to the IANA (Internet Assigned Numbers Authority). See + <url id="http://www.iana.org/assignments/media-types"> and RFC 6838 + for details. This information will then propagate to the systems + discovering file media types in Debian, provided by the + <package>shared-mime-info</package>, + <package>mime-support</package> and <package>file</package> + packages. If registration and propagation can not be waited for, + support can be asked to the maintainers of the packages mentioned + above. + </p> + + <p> + For files that are produced and read by a single application, it + is also possible to declare this association to the + <em>Shared MIME Info</em> system by installing in the directory + <file>/usr/share/mime/packages</file> a file in the XML format + specified at <url id="http://standards.freedesktop.org/shared-mime-info-spec/latest/">. + </p> + </sect1> </sect> <sect> -- To UNSUBSCRIBE, email to debian-policy-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? 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