1. Related Links:
http://standards.freedesktop.org/desktop-entry-spec/desktop-entry-spec-latest.html#mime-types
http://www.freedesktop.org/wiki/Specifications/mime-actions-spec
http://standards.freedesktop.org/shared-mime-info-spec/shared-mime-info-spec-0.18.html
http://www.freedesktop.org/wiki/Specifications/shared-mime-info-spec
2. Overview of What is involved:
3. Directories and Files Managing MIME (database) and Application (Database)
3.1 Shared MIME-Info Database
Is a file-based database of all known MIME types. The database's files are located in the following directories (further down overrides)
/usr/share/mime/*/*.xml, /usr/local/share/mime/*/*.xml, and~/.local/share/mime/*/*.xml (if they exist, and in this order).Each has maintains an application which manipulates this database - for example, in KDE, Configure Desktop -> File Association
The database starts in directory named "mime" - for example /usr/share/mime - which has following files
all
application
audio
...
packages
...
text
(etc)
As an example, /usr/share/mime/text directory has following files:
css.xml
html.xml
plain.xml
richtext.xml
sgml.xml
vnd.graphviz.xml
x-cobol.xml
x-erlang.xml
x-fortran.xml
(etc)
As an example, html.xml defines MIME type "html", this way:
So html.xml defines:
The MIME type name (html)
The MIME Parent Type (text/plain)
Description (in all languages)
List of File Extensions which will assume this MIME Type
Application section of the the Shared MIME-Info database
this is in the mime/packages directory.
For example, doing ./configure && make install with Firefox should create /usr/share/mime/packages/firefox.xml (but it does NOT).
3.2 Desktop Entries for Applications http://standards.freedesktop.org/desktop-entry-spec/desktop-entry-spec-latest.html#mime-types
KDE and GNOME desktop environments have adopted a similar format for "desktop entries", or configuration files describing how a particular program is to be launched, how it appears in menus, etc. These files end with extension .desktop. The suffix "desktop" seems a misnomer - it seems .desktop files simply describe Applications
Desktop Entries Database (=Application Definitions Database) (NOT Part of MIME-Info Database, but uses it)
This database is located in /usr/share/applications/*, /usr/local/share/applications/*, and ~/.local/share/applications/* (if they exist, and in this order). Further, if desktop=KDE, ~.kde4/share/apps/* is also part of the database.The /usr/share/applications directory has following files
kde4
YaST2
google-chrome.desktop
firefox.desktop
gimp.desktop
emacs.desktop
....etc
for example, /usr/share/applications/firefox.desktop contains
[Desktop Entry]
X-SuSE-translate=true
Categories=Network;WebBrowser;GTK;
Encoding=UTF-8
Name=Firefox
GenericName=Web Browser
Comment=Web Browser
TryExec=firefox
Exec=firefox %u
Icon=firefox
Terminal=false
StartupNotify=true
MimeType=text/html;text/xml;application/xhtml+xml;application/vnd.mozilla.xul+xml;text/mml;application/x-xpinstall;x-scheme-handler/http;x-scheme-handler/https;
Type=Application
Note: The MIME Type list above can be expanded to list of file extensions. This is displayed in "File Association" settings.
Note: To add a new application, such as emacs-client, that appears in popups of right click open-with, simply
- create /usr/share/applications/emacs-client.desktop
- copy contents from emacs.desktop
- modify Exec=run-emacs-client.sh
- modify Name=Emacs Client
3.3 ~/.local/share/applications/mimeapp.list - user defined order of application preference when open
- maintains ORDER of Applications Which Understand a certain MimeType
- Format
[Added Associations] mimetype1=foo1.desktop;foo2.desktop;foo3.desktop; mimetype2=foo4.desktop; [Removed Associations] mimetype1=foo5.desktop;
- Sample:
[Added Associations]
application/x-shellscript=run-emacs-client.sh.desktop;
text/x-emacs-lisp=run-emacs-client.sh.desktop;
[Added KDE Service Associations]
application/xhtml+xml=kwebkitpart.desktop;khtml.desktop;
application/xml=kwebkitpart.desktop;khtml.desktop;
text/html=kwebkitpart.desktop;khtml.desktop;
