diff options
Diffstat (limited to 'trunk/gnome2-system-admin-guide/C/mimetypes.xml')
| -rw-r--r-- | trunk/gnome2-system-admin-guide/C/mimetypes.xml | 900 |
1 files changed, 0 insertions, 900 deletions
diff --git a/trunk/gnome2-system-admin-guide/C/mimetypes.xml b/trunk/gnome2-system-admin-guide/C/mimetypes.xml deleted file mode 100644 index 15ca2a8..0000000 --- a/trunk/gnome2-system-admin-guide/C/mimetypes.xml +++ /dev/null @@ -1,900 +0,0 @@ -<?xml version="1.0" encoding="UTF-8"?> -<chapter id="mimetypes-0"> - <title>MIME Types</title> - <anchor id="mimetypes-TBL-3"/> - <anchor id="mimetypes-TBL-6"/> - <anchor id="mimetypes-TBL-8"/> - - <highlights> - <para>This chapter describes how applications detect MIME types, how to - register MIME types, and how to add applications to the GNOME - Desktop.</para> - </highlights> - - <para>The purpose of this chapter is to make it easy for an administrator to - understand how to configure different parts of the MIME database and give an - general overview of the MIME system. Therefore we will - <emphasis>not</emphasis> attempt to go into details where it is not - necessary. For the gory details, it is recommended that you refer to the - <ulink url="http://www.freedesktop.org/Standards/shared-mime-info-spec">XDG - shared mime info specification</ulink>.</para> - - <sect1 id="mimetypes-intro"> - <title>Introduction to MIME Types</title> - <anchor id="mimetypes-1"/> - - <indexterm> - <primary>MIME types</primary> - - <secondary>introduction</secondary> - </indexterm> - - <para>A <firstterm>Multipurpose Internet Mail Extension</firstterm> - [<acronym>MIME</acronym>] type identifies the format of a file. - Applications such as Internet browsers and email applications use the MIME - type of a file to decide which actions to perform on it. For example, an - email application can use the MIME type to detect the format of an - attachment and choose an appropriate viewer for the file, such as opening - a text document with <application>gedit</application>.</para> - - <para>As another example, the <application>Nautilus</application> file - manager needs to know the MIME type of a file to perform the following - tasks:</para> - - <itemizedlist> - <listitem> - <para>Open the file in an appropriate application.</para> - </listitem> - - <listitem> - <para>Display a string that describes the type of file.</para> - </listitem> - - <listitem> - <para>Display an appropriate icon to represent the file.</para> - </listitem> - - <listitem> - <para>Display a list of other applications that can open the - file.</para> - </listitem> - </itemizedlist> - - <para>MIME types were originally proposed as a standard for identifying - the message body of an e-mail message. Now, many systems use MIME types to - identify the format of arbitrary files on the file system. MIME types are - composed of a top-level <emphasis>media type</emphasis> followed by a - <emphasis>subtype identifier</emphasis>, separated by a forward slash - character, <quote><literal>/</literal></quote>. One example of a MIME type - is <literal>image/jpeg</literal>. The media type in this example is - <quote><literal>image</literal></quote> and the subtype identifier is - <quote><literal>jpeg</literal></quote>. The top-level media type is meant - to be a general categorization about the content of the file, while the - subtype identifer is meant to specifically identify the format of the - file.</para> - - <para>There are eight media types currently blessed by the - <acronym>IANA</acronym> [Internet Assigned Naming Authority]. These eight - media types are <simplelist type="inline"> - <member>application</member> - - <member>audio</member> - - <member>image</member> - - <member>message</member> - - <member>model</member> - - <member>multipart</member> - - <member>text</member> - - <member>video</member> - </simplelist>. Many subtypes exist for each media type; for more - information, see <ulink - url="http://www.iana.org/assignments/media-types/">MIME Media - Types</ulink> at the <ulink url="http://www.iana.org/">IANA</ulink> web - site.</para> - - <para>Implementation of MIME types in GNOME follows the <ulink - url="http://www.freedesktop.org/Standards/shared-mime-info-spec">XDG - shared mime info specification</ulink>. This specification provides the - following advantages:</para> - - <itemizedlist> - <listitem> - <para>Standard locations for all MIME related files.</para> - </listitem> - - <listitem> - <para>A standard way for applications to register information about a - new MIME type.</para> - </listitem> - - <listitem> - <para>A standard way to retrieve the MIME type for a file.</para> - </listitem> - - <listitem> - <para>A standard way to retrieve information about a MIME type.</para> - </listitem> - </itemizedlist> - - <para>The rest of the chapter describes the files and directories that - make up the MIME database, details about source XML files, how to create - or modify MIME types, how to register applications as handlers for certain - MIME types and finally, how to add an application to the GNOME - desktop.</para> - </sect1> - - <sect1 id="mimetypes-database"> - <title>The MIME Database</title> - <anchor id="mimetypes-4"/> - <anchor id="mimetypes-5"/> - - <indexterm> - <primary>MIME types</primary> - - <secondary>database</secondary> - </indexterm> - - <para>The MIME database is a collection of files that make up:</para> - - <itemizedlist> - <listitem> - <para>The set of known MIME types</para> - </listitem> - - <listitem> - <para>The method for determing the MIME type of a file</para> - </listitem> - - <listitem> - <para>Meta information regarding a MIME type, such as a human readable - description to use when displaying files of this type.</para> - </listitem> - </itemizedlist> - - <sect2 id="mimetypes-location"> - <title>Location</title> - - <para>As an administrator, the most important and basic step to - understanding the MIME system is learning the locations where these - files are stored. Since the <ulink - url="http://www.freedesktop.org/Standards/shared-mime-info-spec">XDG - shared mime info specification</ulink> was drafted by the X Desktop - Group, it also makes use of the <ulink - url="http://www.freedesktop.org/wiki/Standards/basedir-spec">XDG base - directory specification</ulink>. It is highly recommended that you - familiarize yourself with this specification, as it is also important - for other system administration tasks such as editing menus. A brief - summary of the directory locations as pertaining to the MIME - specification is given below.</para> - - <para>The MIME database is created from the set of files located in the - <filename>$XDG_DATA_HOME/mime</filename> and - <filename>$XDG_DATA_DIRS/mime</filename> directories. If - these environment variables are unset, then they default to the values - <filename>~/.local/share</filename> and - <filename>/usr/local/share:/usr/share</filename> respectively. As can be - seen from the default value for <envar>$XDG_DATA_DIRS</envar> , each - environment variable is actually a colon separated list of directories. - The user's database at - <filename>$XDG_DATA_HOME/mime</filename> has precedence - over the system database at - <filename>$XDG_DATA_DIRS/mime</filename> when conflicting - definitions are encountered. Similar to the <citetitle>XDG shared mime - specification</citetitle>, we will refer to this set of directories as - <literal><MIME></literal> in the rest of this document.</para> - - <para>For example, assuming default paths for the environment variables, - <quote>Load - <filename><MIME>/text/plain.xml</filename></quote> - means to load the following files:</para> - - <itemizedlist> - <listitem> - <para><filename>~/.local/share/mime/text/plain.xml</filename></para> - </listitem> - - <listitem> - <para><filename>/usr/local/share/mime/text/plain.xml</filename></para> - </listitem> - - <listitem> - <para><filename>/usr/share/mime/text/plain.xml</filename></para> - </listitem> - </itemizedlist> - </sect2> - - <sect2 id="mimetypes-contents"> - <title>Contents</title> - - <para>The following is a list of directories and files that are found - inside the MIME database along with brief descriptions:</para> - - <variablelist> - <varlistentry> - <term><filename><MIME>/packages/</filename></term> - - <listitem> - <para>This directory contains any number of XML files, each of - which describe a collection of MIME types. By default, the - <filename>freedesktop.org.xml</filename> file is installed in the - <filename>/usr/share/mime/packages</filename> directory. This file - contains all the default MIME types that are widely used and - recognized.</para> - - <para>Applications which provide information about new MIME types - are to install a <emphasis>single</emphasis> new XML file here. - Depending on the prefix where the application is installed, it - will create the file in the <filename>/mime/package</filename> - subdirectory of one of the directories in - <envar>$XDG_DATA_HOME:$XDG_DATA_DIRS</envar>. For example, an - application installed to <filename>/usr/bin</filename> should - install a new source XML file to the - <filename>/usr/share/mime/packages</filename> directory. For more - information about the XML files in the - <filename>packages</filename> directory, please see <xref linkend="mimetypes-source-xml"/>.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><filename><MIME>/<replaceable>MEDIA</replaceable>/<replaceable>SUBTYPE</replaceable>.xml</filename></term> - - <listitem> - <para>These directories and files are automatically generated from - the collection of source XML files in the - <filename><MIME>/packages/</filename> subdirectory by the - <application>update-mime-database</application> application. For - example, for each <literal>mime-type</literal> element in the - <filename>/usr/share/mime/packages/freedesktop.org.xml</filename> - file, a directory is created at - <filename>/usr/share/mime/</filename> with the <emphasis>media - type</emphasis> of the MIME type. An XML file is created in that - directory with the <emphasis>subtype identifier</emphasis> of that - MIME type as well. The contents of the created XML file include - comments (and translations for them), subclasses designations and - aliases.</para> - - <example> - <title>Example: - <filename>/usr/share/mime/text/plain.xml</filename> file</title> - - <para><programlisting><?xml version='1.0' encoding='utf-8'?> -<mime-type xmlns="http://www.freedesktop.org/standards/shared-mime-info" type="text/plain"> -<!--Created automatically by update-mime-database. DO NOT EDIT!--> - <comment>plain text document</comment> - <!-- possibly more translations --> - <comment xml:lang="es">documento de texto sencillo</comment> - <comment xml:lang="eu">testu soileko dokumentua</comment> - <comment xml:lang="fi">perustekstiasiakirja</comment> - <comment xml:lang="fr">document plein texte</comment> - <!-- possibly more translations --> -</mime-type> -</programlisting>This file is generated by the - <application>update-mime-database</application> application, - using the default source XML file - <filename>freedesktop.org.xml</filename>.</para> - </example> - </listitem> - </varlistentry> - - <varlistentry> - <term><filename><MIME>/globs</filename></term> - - <listitem> - <para>Contains one line with a MIME type and a glob pattern, - separated by a colon. Files which match the glob pattern are - resolved to the MIME type specified before the colon. There are - special rules about how filenames are matched by the glob pattern; - for more details see the <citetitle>XDG shared mime - specification</citetitle>.</para> - - <para>This file is also generated by the - <application>update-mime-database</application> application, using - the default source XML file - <filename>freedesktop.org.xml</filename>.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><filename><MIME>/magic</filename></term> - - <listitem> - <para>A binary file which contains information on how to resolve - MIME types by <quote>sniffing</quote> the content of the file. - This is generally a set of one or more rules such as <quote>check - for the string <literal>%PDF- </literal>at byte offset 0 in the - file; if found, assign it the MIME type - <literal>application/pdf</literal></quote>.</para> - - <para>This file is also generated by the - <application>update-mime-database</application> - application.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><filename><MIME>/XMLnamespaces</filename></term> - - <listitem> - <para>Contains a mapping of XML namespaces to MIME types. Each - line contains three fields, the namespace, the localName and the - MIME type. Each field is separated by a space. If the localName is - empty, then there are two spaces between the namespace and the - MIME type.</para> - - <para>This file is also generated by the - <application>update-mime-database</application> - application.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><filename><MIME>/aliases</filename></term> - - <listitem> - <para>Contains a list of aliases for each MIME type. An alias is - simply a MIME type that is sometimes known as another type. For - each line in this file there are two fields: the first field is - the alias name, and the second field is the MIME type. The fields - are separated by a space.</para> - - <para>This file is also generated by the - <application>update-mime-database</application> - application.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><filename><MIME>/subclasses</filename></term> - - <listitem> - <para>Contains a list of subclassed MIME types and their - <quote>parent</quote> MIME type. From the <citetitle>XDG shared - mime specification:</citetitle><blockquote> - <para>A type is a subclass of another type if any instance of - the first type is also an instance of the second. For example, - all image/svg files are also text/xml, text/plain and - application/octet-stream files. Subclassing is about the - format, rather than the catagory of the data (for example, - there is no 'generic spreadsheet' class that all spreadsheets - inherit from).</para> - </blockquote>The format of this file is similar to the - <filename>aliases</filename> file. Each line contains two fields, - where the first field is the subclassed MIME type and the second - field is the parent MIME type. Each field is separated by a - space.</para> - - <para>This file is also generated by the - <application>update-mime-database</application> - application.</para> - </listitem> - </varlistentry> - </variablelist> - </sect2> - - <sect2 id="mimetypes-refresh"> - <title>Refreshing the MIME Database</title> - - <para>Understanding how to refresh the MIME database is important for - administrators who wish to add new MIME types to the system, or - otherwise modify information about a MIME type. The application - <application>update-mime-database</application> is intended for this - purpose.</para> - - <para>For example, if an application installs information about a new - MIME type to <filename>/usr/share/mime/packages/diff.xml</filename>, - then <application>update-mime-database</application> must be called with - the parameter <filename>/usr/share/mime</filename>.</para> - - <screen><prompt>#</prompt> <userinput>update-mime-database /usr/share/mime</userinput> -<computeroutput>*** -* Updating MIME database in /usr/share/mime... -*** -</computeroutput></screen> - - <para>The MIME database is refreshed by scanning all the source XML - files in the directory - <filename><MIME>/packages</filename>.</para> - </sect2> - </sect1> - - <sect1 id="mimetypes-source-xml"> - <title>The source XML files</title> - <anchor id="mimetypes-11" /> - <anchor id="mimetypes-12" /> - <anchor id="mimetypes-2" /> - - <indexterm> - <primary>MIME types</primary> - - <secondary>source XML files</secondary> - </indexterm> - - <para>Located in the <filename><MIME>/packages</filename> directory, - these XML files provide all the information regarding MIME types that is - installed into the database by the - <application>update-mime-database</application> application. There are a - few rules about the XML file itself:</para> - - <itemizedlist> - <listitem> - <para>It must specify the namespace as - <quote><literal>http://www.freedesktop.org/standards/shared-mime-info</literal></quote></para> - </listitem> - - <listitem> - <para>The root element must be <literal>mime-info</literal></para> - </listitem> - - <listitem> - <para>Zero or more <literal>mime-type</literal> elements can be - specified as children of the <literal>mime-info</literal> element. The - <literal>type</literal> attribute is used to specify the MIME type - that is being defined.</para> - </listitem> - </itemizedlist> - - <para>By default, the <filename>freedesktop.org.xml</filename> file is - installed to the <filename>packages</filename> directory in one of the - <filename><MIME></filename> paths (usually - <filename>/usr/share/mime/packages</filename>).</para> - - <para><xref linkend="mimetypes-mimeinfo-elements" /> gives a brief - description for each of the elements that can occur as children to the - <literal>mime-type</literal> element.</para> - - <table frame="topbot" id="mimetypes-mimeinfo-elements"> - <title>Child elements of <literal><mime-info></literal></title> - - <tgroup cols="2" colsep="0" rowsep="0"> - <colspec colwidth="44.90*" /> - - <colspec colwidth="59.10*" /> - - <thead> - <row rowsep="1"> - <entry>Element (and attributes)</entry> - - <entry>Description</entry> - </row> - </thead> - - <tbody> - <row> - <entry><literal><glob - pattern="<replaceable>*.xyz</replaceable>"></literal></entry> - - <entry>This element specifies a glob pattern against filenames. If - the filename matches, then it is assigned the MIME type of the - parent <literal>mime-type</literal> element. The - <literal>pattern</literal> attribute is mandatory.</entry> - </row> - - <row> - <entry><literal><magic - priority="<replaceable>50</replaceable>"></literal></entry> - - <entry>This element contains a list of <literal>match</literal> - elements as its children. The <literal>priority</literal> - attribute is optional, and specifies a priority between 0 and 100, - with 100 being the highest matching priority. Each child - <literal>match</literal> element has three required attributes: - <simplelist type="inline"> - <member><literal>type</literal></member> - - <member><literal>offset</literal></member> - - <member><literal>value</literal></member> - </simplelist> and a fourth optional attribute, - <literal>mask</literal>. For details on these attributes, see the - <ulink - url="http://www.freedesktop.org/Standards/shared-mime-info-spec">XDG - shared mime info specification</ulink>.</entry> - </row> - - <row> - <entry><literal><alias - type="<replaceable>media</replaceable>/<replaceable>subtype</replaceable>"></literal></entry> - - <entry>This element defines an alias for the parent - <literal>mime-type</literal> element. An alias is simply a MIME - type that is sometimes known as another type. For example, - <literal>application/x-pdf</literal> is an alias for the MIME type - <literal>application/pdf</literal>.</entry> - </row> - - <row> - <entry><literal><sub-class-of - type="<replaceable>media</replaceable>/<replaceable>subtype</replaceable>"></literal></entry> - - <entry>This element defines the parent - <literal>mime-type</literal> element as a subclass of the MIME - type specified in the <literal>type</literal> attribute. For - example, <literal>image/svg</literal> is a sub class of the MIME - type <literal>text/xml</literal>, <literal>text/plain</literal>, - and <literal>application/octet-stream</literal>.</entry> - </row> - - <row> - <entry><literal><comment - xml:lang="<replaceable>locale</replaceable>"></literal></entry> - - <entry>This element provides a human readable description for the - MIME type. There can be zero or more occurrences of this element - as long as each one contains a unique value for the - <literal>xml:lang</literal> attribute.</entry> - </row> - - <row> - <entry><literal><root-XML - namespaceURI="<replaceable>namespace</replaceable>" - localName=""></literal></entry> - - <entry>If a file is determined to an XML file, then this element - helps to further classify it through the use of the - <literal>namespaceURI</literal> and <literal>localName</literal> - attributes, both of which are required. The attribute - <literal>namespaceURI</literal> is the namespace of the document, - and <literal>localName</literal> is the name of the root element - for the document. If <literal>localName</literal> is present but - its value is empty, then the root element may have any name, but - the namespace must still match.</entry> - </row> - </tbody> - </tgroup> - </table> - - <para>The easiest way to understand these files is to take a look at an - example. Borrowing from the <citetitle>XDG shared mime - specification</citetitle>, <xref linkend="mimetypes-source-xml-example" /> - displays the contents of a source XML file called - <filename>diff.xml</filename>. This example defines the MIME type - <literal>text/x-diff</literal>. There are multiple - <literal>comment</literal> elements which give a human readable name to - the MIME type in a number of different languages. This MIME type has both - rules for matching through glob patterns <emphasis>and</emphasis> through - the use of content <quote>sniffing</quote> (better known as - <filename>magic</filename> rules). Any file with the extension - <literal>.diff</literal> or <filename>.patch</filename> will resolve to - this MIME type. Additionally any file whose contents start with the - strings specified in the <literal>value</literal> attributes of the - <literal>match</literal> element, will resolve to the - <literal>text/x-diff</literal> MIME type.</para> - - <para>The order in which glob patterns and magic rules apply is beyond the - scope of this document. For details on this, see the <ulink - url="http://www.freedesktop.org/Standards/shared-mime-info-spec">XDG - shared mime info specification</ulink>.</para> - - <example id="mimetypes-source-xml-example"> - <title>Example of a source XML file: - <filename>diff.xml</filename></title> - - <programlisting><?xml version='1.0'?> -<mime-info xmlns='http://www.freedesktop.org/standards/shared-mime-info'> - <mime-type type="text/x-diff"> - <comment>Differences between files</comment> - <comment xml:lang="af">verskille tussen lêers</comment> - <!-- more translated comment elements --> - <magic priority="50"> - <match type="string" offset="0" value="diff\t"/> - <match type="string" offset="0" value="***\t"/> - <match type="string" offset="0" value="Common subdirectories: "/> - </magic> - <glob pattern="*.diff"/> - <glob pattern="*.patch"/> - </mime-type> -</mime-info></programlisting> - </example> - </sect1> - - <sect1 id="mimetypes-modifying"> - <title>Modifying MIME types</title> - - <indexterm> - <primary>MIME types</primary> - - <secondary>verifying changes</secondary> - </indexterm> - - <indexterm> - <primary>MIME types</primary> - - <secondary>modifying</secondary> - </indexterm> - - <para>You should never directly modify the source XML files that are - installed to the <filename><MIME>/packages</filename> directory by - applications. Instead, modify the <filename>Overrides.xml</filename> file. - This file has precedence over all other source XML files installed into - the same <filename>packages</filename> directory. If you are an - application author, then this rule does not apply. You should create a new - source XML file and place it in the proper - <filename><MIME>/packages</filename> directory (your - <filename>Makefile</filename> will take care of this, of course).</para> - - <para>You can modify the MIME database for all users on the system or for - a particular user depending on the location of the file you change. To - modify the database for all users, make changes to the file - <filename>Overrides.xml</filename> in the - <filename>$XDG_DATA_DIRS/mime/packages</filename> - directory. To modify the database for a single user, make changes to the - file <filename>Overrides.xml</filename> in the - <filename>$XDG_DATA_HOME/mime/packages</filename> - directory.</para> - - <para>After changes are made, you must always run the - <application>update-mime-database</application> application, with the - directory location of the MIME database as the first parameter.</para> - - <sect2 id="mimetypes-addmodify"> - <title>Adding or Modifying MIME types</title> - - <para>To add one or more MIME types for all users:</para> - - <orderedlist> - <listitem> - <para>Create or modify an existing - <filename>Overrides.xml</filename> source XML file, containing the - definitions for the MIME types. For more information, see <xref - linkend="mimetypes-source-xml" />.</para> - </listitem> - - <listitem> - <para>Place the <filename>Overrides.xml</filename> file in the - <filename>/usr/share/mime/packages</filename> directory.</para> - </listitem> - - <listitem> - <para>Update the MIME database by running - <application>update-mime-database</application> using the system - account.<screen><userinput>update-mime-database /usr/share/mime</userinput></screen></para> - </listitem> - </orderedlist> - - <para>To add one or more MIME types for a single user, follow the same - steps, except place your <filename>Overrides.xml</filename> file in the - <filename>~/.local/share/mime/packages</filename> directory. - Additionally, call <application>update-mime-database</application> with - <filename>~/.local/share/mime/packages</filename> as the first - parameter.</para> - </sect2> - - <sect2 id="mimetypes-verifying"> - <title>Verifying Changes</title> - <anchor id="mimetypes-10"/> - - <para>After you have made a change to the MIME database and refreshed - its contents, you can verify that the change has taken effect using the - <application>gnomevfs-info</application> application. This application - prints the MIME type and other useful information about a file.</para> - - <para>Running <application>gnomevfs-info</application> on a SVG file - gives you the output shown below. You'll notice the default application - for this MIME type is <filename>eog.desktop</filename>; We will discuss - default applications in <xref linkend="mimetypes-registering" />.</para> - - <screen><prompt>$</prompt> <userinput>gnomevfs-info mime-diagram.svg</userinput> -<computeroutput>Name : mime-diagram.svg -Type : Regular -MIME type : image/svg+xml -Default app : eog.desktop -Size : 14869 -Blocks : 32 -I/O block size : 4096 -Local : YES -SUID : NO -SGID : NO -Sticky : NO -Permissions : 600644 -Link count : 1 -UID : 1000 -GID : 100 -Access time : Wed Feb 22 18:24:47 2006 -Modification time : Wed Feb 22 18:24:42 2006 -Change time : Wed Feb 22 18:24:42 2006 -Device # : 775 -Inode # : 297252 -Readable : YES -Writable : YES -Executable : NO</computeroutput> -<prompt>$</prompt> -</screen> - - <para><xref linkend="mimetypes-newtype-example" /> walks through the steps of - creating a new MIME type and then verifying the changes using - <application>gnomevfs-info</application>.</para> - </sect2> - - <sect2 id="mimetypes-newtype-example"> - <title><literal>application/x-newtype</literal> Example</title> - - <para>To create (or override) a MIME type and verify the changes:</para> - - <orderedlist> - <listitem> - <para>Make a new, empty file in your home directory called - <filename>testing.xyz</filename>.</para> - </listitem> - - <listitem> - <para>Use <application>gnomevfs-info</application> on the file to - find out the MIME type.The MIME type for this file should be - detected as <literal>text/plain</literal> because there are not any - glob patterns or magic rules that match it<footnote> - <para>When no glob patterns or magic rules match a file, then it - is resolved to the MIME type <literal>text/plain</literal> if it - contains textual data or - <literal>application/octet-stream</literal> for binary data. If - the file is empty, then it defaults to - <literal>text/plain</literal>.</para> - </footnote>.</para> - </listitem> - - <listitem> - <para>Create (or modify) the <filename>Overrides.xml</filename> file - as described in <xref linkend="mimetypes-addmodify" /> with the - contents given in <xref linkend="mimetypes-overrides-xml" />.</para> - </listitem> - - <listitem> - <para>Refresh the database using - <application>update-mime-database</application>.</para> - </listitem> - - <listitem> - <para>Use <application>gnomevfs-info</application> to verify that - your change has taken effect. You should see the MIME type for the - <filename>testing.xyz</filename> file resolved as - <literal>application/x-newtype</literal>.</para> - - <screen><prompt>$</prompt> <userinput>gnomevfs-info testing.xyz | grep MIME -</userinput><computeroutput>MIME type : application/x-newtype -</computeroutput><prompt>$</prompt></screen> - </listitem> - </orderedlist> - - <example id="mimetypes-overrides-xml"> - <title><filename>Overrides.xml</filename> file</title> - - <programlisting><?xml version='1.0' encoding='utf-8'?> -<mime-info xmlns="http://www.freedesktop.org/standards/shared-mime-info"> - <mime-type type="application/x-newtype"><comment>new mime type</comment><glob pattern="*.xyz"/></mime-type> -</mime-info></programlisting> - </example> - </sect2> - </sect1> - - <sect1 id="mimetypes-registering"> - <title>Registering Applications for MIME Types</title> - - <anchor id="mimetypes-7" /> - - <indexterm> - <primary>MIME types</primary> - - <secondary>registering applications for</secondary> - </indexterm> - - <indexterm> - <primary>applications</primary> - - <secondary>registry</secondary> - </indexterm> - - <para>Registering applications to handle MIME types is fairly - straightforward. Applications are registered by creating a - <literal>MimeType</literal> key in their <filename>.desktop</filename> - entry file and listing each MIME type separated by a semicolon. The - <literal>MimeType</literal> key should only be used in - <filename>.desktop</filename> files whose <literal>Type</literal> key has - the value <quote><literal>Application</literal></quote>. For more - information on <filename>.desktop</filename> files, see <xref - linkend="menustructure-desktopentry" />.</para> - - <para>After creating or modifying a <filename>.desktop</filename> entry - file, you must update the application database using the - <application>update-desktop-database</application> application (very - similar to <application>update-mime-database</application>, except it does not take a - parameter). This will create a - <filename>mimeinfo.cache</filename> file in the - <filename>applications</filename> subdirectory for each directory in - <filename>$XDG_DATA_HOME:$XDG_DATA_DIRS</filename>. - The cache file is necessary so that all the <filename>.desktop</filename> - files do not need to be scanned for just the <literal>MimeType</literal> - key, as this causes unnecessary disk I/O.</para> - - <para>Default applications to use for specific MIME types should be - specified in a file called <filename>defaults.list</filename>. This file - is located in the <filename>applications</filename> subdirectory for each - directory in <envar>$XDG_DATA_HOME</envar> and - <envar>$XDG_DATA_DIRS</envar>. The format for this file consists of the - MIME type, the <literal>=</literal> symbol and the Desktop File ID (which - is the filename for the desktop entry file). <xref - linkend="mimetypes-registering-example" /> is a short example of a - <filename>defaults.list</filename> file in a user's - <filename>~/.local/share/applications</filename> directory.</para> - - <example id="mimetypes-registering-example"> - <title>A User's <filename>defaults.list</filename> file</title> - - <programlisting>[Default Applications] -application/pdf=evince.desktop -text/html=epiphany.desktop -text/plain=gedit.desktop -image/jpeg=eog.desktop -image/png=eog.desktop -text/xml=gedit.desktop -</programlisting> - </example> - - <note> - <title>XDG Desktop Entry Specification</title> - - <para>How to register MIME types for applications is part of the <ulink - url="http://www.freedesktop.org/wiki/Standards/desktop-entry-spec">XDG desktop entry specification</ulink>, rather than the - <ulink - url="http://www.freedesktop.org/Standards/shared-mime-info-spec">XDG - shared mime info specification</ulink>.</para> - </note> - </sect1> - - <sect1 id="mimetypes-9"> - <title>Adding an Application to the GNOME Desktop</title> - - <indexterm> - <primary>MIME types</primary> - - <secondary>adding applications</secondary> - </indexterm> - - <indexterm> - <primary>applications</primary> - - <secondary>adding</secondary> - </indexterm> - - <para>To add an application to the GNOME Desktop, perform the following - steps:</para> - - <orderedlist> - <listitem> - <para>Add a menu item for the application. For more information on how - to add an item to a menu, see <xref - linkend="menustructure-2" />.</para> - </listitem> - - <listitem> - <para>Add an icon for the application to - <filename>/usr/share/icons/<replaceable>theme-name</replaceable>/<replaceable>icon-size</replaceable>/apps</filename>. - For more information on icons and themes, see <xref - linkend="themes-11" />.</para> - </listitem> - - <listitem> - <para>If the application uses a new MIME type, add a source XML file - to the MIME database. For more information, see <xref - linkend="mimetypes-modifying" />.</para> - </listitem> - - <listitem> - <para>If the application uses a new MIME type, add an icon for the - MIME type to - <filename>/usr/share/icons/<replaceable>theme-name</replaceable>/<replaceable>icon-size</replaceable>/mimetypes</filename>. - For more information on icons and themes, see <xref - linkend="themes-0" />.</para> - </listitem> - - <listitem> - <para>To associate the application with a MIME type, include a - <literal>MimeType</literal> key in your <filename>.desktop</filename> - file. For more information, see <xref - linkend="mimetypes-registering" />.</para> - </listitem> - </orderedlist> - </sect1> -</chapter> |