debian-jessie-main.xml.gz
. For Fedora 20 (Heisenbug) updates it would be fedora-20-updates.xml.gz
. 3rd-party repositories use a vendor name and repository-name combination, for example Ubuntu PPAs might get ppa-ubuntu12.04-username-foobar.xml
.
/usr/share/app-info/xmls
stores all AppStream data which has been installed via software packages, while /var/cache/app-info/xmls
stores application data which was downloaded by the package manager or placed there by other tools (e.g. Listaller). The XML files can either be plain files or be compressed with gzip. It is always a good idea to compress the files, because they tend to become quite large.
<components>
tag as root element. It has all the <component>
, <application>
, <font>
and <inputmethod>
elements as children.
<components>
element, no matter of which type they are, must at least have an id
, name
, summary
and pkgname
tag. For applications, a icon
tag is also required.
<components>
root node must have two properties: version
declaring the AppStream spec version this file is based on (currently 0.6) and origin
defining the repository-id this AppStream XML file belongs to. This usually matches the filename without extension (see the explanation on how to pick a good filename above).
<id type="desktop">
tag is the same name as the installed .desktop file for the application. Additional identifiers are possible later, but right now desktop
is the only supported type.
<project_license>
tag is indicating the license of your project/application. It should be a string in SPDX format. Licenses may be combined using and and or logic. Possible values include:
<description> <p> Power Statistics is a program used to view historical and current battery information and will show programs running on your computer using power. </p> <p>Example list:</p> <ul> <li>First item</li> <li>Second item</li> </ul> <p> You probably only need to install this application if you are having problems with your laptop battery, or are trying to work out what programs are using significant amounts of power. </p> </description>
<description/>
tag itself has a language property and contain the translated paragraphs for the given language. This allows faster parsing of the Appstream XML file, and does not increase it's size much, as long as it is compressed.
<project_group>
tag identifies a project with a specific upstream umbrella project. Known values include GNOME, KDE, XFCE, LXDE, Mozilla
and MATE
, although other umbrella projects like Yorba
would make sense too.
Note
<icon>
tag describes the application's icon. It can be of the type stock
, cached
, local
, or url
.
stock
icons are loaded from stock. The icon name should never include any file-extension or path.
cached
icons are loaded from the AppStream icon cache. The icon tag should contain the icon file name, including it's extension.
local
icons are reserved for AppStream data installed by local applications or via 3rd-party application installers, such as Listaller. They should specify a full file path.
remote
icons loaded from a remote URL. This is currently not implemented anywhere, but might be used in future.
<icon type="stock">gimp</icon> <icon type="cached">firefox.png</icon> <icon type="local">/usr/share/pixmaps/foobar.png</icon> <icon type="remote">http://example.com/icons/foobar.png</icon>
<icon/>
tags might be combined for one application, e.g. to define a stock
icon and a cached
icon. Software-Centers should always prefer the stock icon, if it is available, and fall back to the other icon types if they can not find it. The libappstream library makes it easy to do that, if you are not accessing the Xapian database manually.
cached
over local
over remote
icons when setting the non-stock icon for the application.
<mimetype>
tags, describing the mime types this application supports. The data can usually be fetched from the Desktop files. Example:
<mimetypes> <mimetype>text/html</mimetype> <mimetype>image/jpeg</mimetype> <mimetype>application/rss+xml</mimetype> </mimetypes>
<category>
tags, describing the categories this application is in. This data is usually taken from Desktop files, a list of categories can be found in the Freedesktop menu spec. Example:
<categories> <category>GNOME</category> <category>GTK</category> <category>Network</category> <category>Telephony</category> </categories>
Deprecated Tags
<appcategories>
with its <appcategory>
child elements is deprecated API. AppStream parsers should handle these tags just like the category
tags, there is no difference except for the name.
<keyword>
tags, describing keywords for the application, to make it easier to find in a software center. The data is taken from Desktop files. Example:
<keywords> <keyword>IDE</keyword> <keyword>development</keyword> <keyword>programming</keyword> </keywords>
<screenshot>
tags, describing screenshots which are available for the application. A screenshot tag my have the attribute type="default"
, marking it as the application's default screenshot, which primarily represents it in a software center.
<screenshot>
is defined by several images of different sizes. All images should have their width and hight set as arguments. Also, one of the images shoukd be marked as type="source"
, indicating that it is the unscaled version of the screenshot. Images of type="thumbnail"
define thumbnails of the screenshot.
<caption>
tag, describing the screenshot's caption. This is usually what the user can see on the image shown. The tag is translatable.
<screenshots> <screenshot type="default"> <caption>Foobar showing kitchen-sink functionality</caption> <caption xml:lang="si">Foobar shoeewing kischän-sünk funzionality</caption> <image type="source" width="800" height="600">http://www.example.org/en_US/main.png</image> <image type="thumbnail" width="200" height="150">http://www.example.org/en_US/main-small.png</image> </screenshot> <screenshot> .... </screenshot> </screenshots>
<compulsory_for_desktop>
tag indicates that the application which the data belongs to is essential for the functionality of the defined desktop environment. Examples for compulsory applications are the GNOME-Shell
by the GNOME-Project, or the Plasma-Desktop
by KDE, as well as things like iBus
or the desktop login manager.
<compulsory_for_desktop>
tag are allowed, so a project can be essential for many desktops. The distributor decides which applications should be made compulsory, however it is generally a good idea to follow upstream's recommendations on that matter.
pkgname
tag.
<release>
tag describes some metainformation about the current release of the described component. It may be present multiple times (for older releases), but a tag for the current version must always be present. A release
tag can have the properties version
and timestamp
which contain the version number and a release timestamp in form of YYYYMMDD.
<release version="1.2" timestamp="20140412" /> <release version="1.0" timestamp="20120826" />
<release/>
tag has a <description/>
tag as parameter, describing the new release briefly, distributors are encouraged to provide 2-4 <release/>
release tags for every component. If no description is provided, one tag is enough.
architectures
tag is present, the component is not available on all architectures the distribution supports. Supported architectures for this component are specified as children using the arch
tag.
<architectures> <arch>i686</arch> </architectures>
<?xml version="1.0"?> <components version="0.6"> <component type="application"> <id>firefox.desktop</id> <pkgname>firefox-bin</pkgname> <name>Firefox</name> <name lang="en_GB">Firefoux</name> <summary>Web browser</summary> <summary lang="fr_FR">Navigateur web</summary> <project_license>MPL-2</project_license> <keywords> <keyword>internet</keyword> <keyword>web</keyword> <keyword>browser</keyword> <keyword lang="fr_FR">navigateur</keyword> </keywords> <icon type="stock">web-browser</icon> <icon type="cached">firefox.png</icon> <categories> <category>network</category> <category>web</category> </categories> <mimetypes> <mimetype>text/html</mimetype> <mimetype>text/xml</mimetype> <mimetype>application/xhtml+xml</mimetype> <mimetype>application/vnd.mozilla.xul+xml</mimetype> <mimetype>text/mml</mimetype> <mimetype>application/x-xpinstall</mimetype> <mimetype>x-scheme-handler/http</mimetype> <mimetype>x-scheme-handler/https</mimetype> </mimetypes> <url type="homepage">http://www.mozilla.com</url> <screenshots> <screenshot type="default"> <image type="source" width="800" height="600">http://www.awesomedistro.example.org/en_US/firefox.desktop/main.png</image> <image type="thumbnail" width="200" height="150">http://www.awesomedistro.example.org/en_US/firefox.desktop/main-small.png</image> </screenshot> </screenshots> <provides> <binary>firefox</binary> </provides> </component> <component> <id>pulseaudio</id> <name>PulseAudio</name> <summary>The PulseAudio sound server</summary> <url type="homepage">http://www.freedesktop.org/wiki/Software/PulseAudio/</url> <project_license>GPLv2</project_license> <provides> <library>libpulse-simple.so.0</library> <library>libpulse.so.0</library> <binary>start-pulseaudio-kde</binary> <binary>start-pulseaudio-x11</binary> </provides> <release version="2.0"/> </component> <component type="font"> <id>LinLibertine_M.otf</id> <name>Libertine</name> <summary>Linux Libertine Open fonts</summary> <font_classifier>Mono</font_classifier> <font_parent>Libertine</font_parent> </component> <!-- more components here! --> </components>