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URL Handler/API rev2

Revision as of 16:06, 19 October 2010

This document describes the second revision of the hildon_uri_* API that was added in rev 2. Please see revision 1 of the API for the background and also information about the basic file format used.

Make sure to read the desktop entry specification.

The utility update-desktop-database from desktop-file-utils is used to handle the new fields that have been added.

Backwards compatibility

This new version of the framework is still compatible with the older version. This means that the old format for URI action in desktop files can still be used. See the rev1 for information about that.

The code uses the existance of the new key 'X-Osso-URI-Actions' in the [Desktop Entry] group. If the key is missing, the file is interpreted using the old format, otherwise using the new format. It is an error to mix those two versions of the format in the same file.

Changes to the format

The previous framework only had a way to handle URIs based on the scheme, not MIME type. One application would handle callto:// URIs, one http://, etc. The new version has been extended to add support for mapping the scheme and MIME type pair to an action. Each application can implement one or more actions.

To support this, the desktop file format for actions has been changed. A new group, [X-Osso-URI-Actions], is used to list all the available actions, and their corresponding schemes. This is added to a normal desktop file, that is, you still need to regular [Desktop Entry] group. An example:

[Desktop Entry]
<... regular desktop file keys ...>

 [X-Osso-URI-Actions]
 http=X-Osso-URI-Action-Add-Bookmark;X-Osso-URI-Action-Open-Browser;X-Osso-URI-Action-Open-Media;
 ftp=X-Osso-URI-Action-Open-Browser;

 [X-Osso-URI-Action-Add-Bookmark]
 Type=Neutral
 MimeType=text/html;...;
 Name=Add Bookmark
 X-Osso-Service=com.nokia.browser
 Method=add_bookmark
 TranslationDomain=browser

 [X-Osso-URI-Action-Open-Browser]
 <... another action described here...>

As you can see, first in the [X-Osso-URI-Actions] group, each scheme supported by the application is listed as a key, and is associated with a list of actions. Each action is then listed as a separate group with the details for the action.

The keys used in each action group are:

• Type: specifes the type of the action
• MimeType: lists the MIME types handled by this action
• Name: the name of the action
• X-Osso-Service: the D-Bus service name to call when performing the action
• Method: the D-Bus method to call
• TranslationDomain: the translation domain to use when translation the name

The keys 'Type', 'X-Osso-Service', 'MimeType', and 'TranslationDomain' are optional.

The keys 'X-Osso-Service' and 'MimeType' are both inherited from the regular [Desktop Entry] group, which means that if you don't specify them in the action group, the values used in the [Desktop Entry] group will be used. If you specify them, the values will override the ones from the [Desktop Entry] group.

The key 'Type' can be one of three values:

• Normal: the default if 'Type' is not specified

A Normal action is the default, and means that the action is mapped to a pair of scheme and MIME type, for example "http" AND "image/png". This type of action will be listed when you ask for actions for a URI that matches the exact pair.

• Neutral: the action applies to ALL mime types, even if none is given

A Neutral action means that it is MIME type neutral, and the action applies to any URI that has the right scheme. Note: this corresponds to the "URI actions" from the older revision of this system, since only the scheme is used to get the actions.

• Fallback: the action applies only when the MIME type is unknown

A Fallback action means that the action applies only when no other action could be found. Currently there is only one intended usecase for this, the "Save Target As..." kind of action in a browser.

Default actions

The uri-default-action.list format as described on the rev-1 fie has been extended as well, but also remains compatible so older files will still work. It now looks like this:

 [X-Osso-URI-Scheme <scheme>]
 <MIME type>=<desktop file>:<action name>

An example of the new and old formats together would look like:

 # For supporting older actions
 [Default Actions]
 https=hildon-browser.desktop;

 # For new actions
 [X-Osso-URI-Scheme http]
 image-png=hildon-browser.desktop:X-Osso-URI-Action-Open
 image-jpeg=hildon-image-viewer.desktop:X-Osso-URI-Action-Open

As you can see, the MIME type needs to have the slashes ('/') replaced by dashes ('-') to comply with the keyfile format that is used.

In addition to this, any fallback actions will use the old [Default Actions] group because you only know the scheme in that case, since the MIME type is unknown. To make sure that this doesn't break existing defaults files, the action name can be added to the end of the desktop file filename, for example:

 [Default Actions]
 <scheme>=<desktop file>:<action name> 

This means it would look like this:

 [Default Actions]
 http=test/browser.desktop:X-Osso-URI-Action-Fallback

 [X-Osso-URI-Scheme http]
 image-gif=test/osso-addressbook.desktop:X-Osso-URI-Action-Add-Bookmark

The added action name can be left out, when referring to old format desktop files, of course, since they don't have the notion of action names.

Example

Here we have some made up examples, first showing files using the older URI action format, then the new one.

Old format VOIP desktop file:

 [Desktop Entry]
 Encoding=UTF-8
 Version=1.0
 Type=Application
 Name=voip_ap_feature_name
 Comment=voip_ap_feature_name_thumb
 Exec=/usr/bin/osso-voip-ui
 Icon=qgn_list_voip
 X-Osso-Service=osso_voip_ui
 X-Osso-Type=application/x-executable
 X-Osso-URI-Actions=voipto;callto;videovoip

 [X-Osso-URI-Action Handler voipto]
 Method=voip_to
 Name=tana_fi_new_call
 TranslationDomain=osso-contact-plugin

 [X-Osso-URI-Action Handler callto]
 Method=voip_to
 Name=tana_fi_new_call
 TranslationDomain=osso-contact-plugin

 [X-Osso-URI-Action Handler videovoip]
 Method=video_voip
 Name=tana_fi_new_call
 TranslationDomain=osso-contact-plugin

New format VOIP desktop file:

 [Desktop Entry]
 Encoding=UTF-8
 Version=1.0
 Type=Application
 Name=voip_ap_feature_name
 Comment=voip_ap_feature_name_thumb
 Exec=/usr/bin/osso-voip-ui
 Icon=general_application_call
 X-Osso-Service=osso_voip_ui
 X-Osso-Type=application/x-executable

 [X-Osso-URI-Actions]
 voipto=X-Osso-URI-Action-Voip-To;
 callto=X-Osso-URI-Action-Voip-To;
 videovoip=X-Osso-URI-Action-Video-Voip-To;

 [X-Osso-URI-Action-Voip-To]
 Method=voip_to
 Name=tana_fi_new_call
 TranslationDomain=osso-contact-plugin

 [X-Osso-URI-Action-Video-Voip-To]
 Method=video_voip
 Name=tana_fi_new_call
 TranslationDomain=osso-contact-plugin

Old format address book desktop file:

 [Desktop Entry]
 Encoding=UTF-8
 Version=1.0
 Type=Application
 Name=addr_ap_address_book
 Comment=addr_ap_address_book_thumb
 Exec=/usr/bin/osso-addressbook
 X-Osso-Service=osso_addressbook
 Icon=qgn_list_addressbook
 StartupWMClass=osso-addressbook
 X-Osso-URI-Actions=mailto;xmpp;sipto;
 MimeType=text/x-vcard

 [X-Osso-URI-Action Handler mailto]
 Method=add_account
 Name=addr_me_cs_addtocontacts
 TranslationDomain=osso-addressbook

 [X-Osso-URI-Action Handler xmpp]
 Method=add_account
 Name=addr_ap_address_book
 TranslationDomain=osso-addressbook

 [X-Osso-URI-Action Handler sipto]
 Method=add_account
 Name=addr_ap_address_book
 TranslationDomain=osso-addressbook

New format address book desktop file:

 [Desktop Entry]
 Encoding=UTF-8
 Version=1.0
 Type=Application
 Name=addr_ap_address_book
 Comment=addr_ap_address_book_thumb
 Exec=/usr/bin/osso-addressbook
 X-Osso-Service=osso_addressbook
 Icon=general_contacts
 StartupWMClass=osso-addressbook
 MimeType=text/x-vcard

 [X-Osso-URI-Actions]
 mailto=X-Osso-URI-Action-Add-Contact;
 xmpp=X-Osso-URI-Action-Add-Account;
 sipto=X-Osso-URI-Action-Add-Account;

 [X-Osso-URI-Action-Add-Contact]
 Method=add_account
 Name=addr_me_cs_addtocontacts
 TranslationDomain=osso-addressbook

 [X-Osso-URI-Action-Add-Account]
 Method=add_account
 Name=addr_ap_address_book
 TranslationDomain=osso-addressbook

Old format browser desktop file:

 [Desktop Entry]
 Encoding=UTF-8
 Version=0.1
 Type=Application
 Name=weba_ap_web_browser
 Comment=weba_ap_web_browser_thumb
 Exec=/usr/bin/browser
 Icon=qgn_list_browser
 X-Window-Icon=qgn_list_browser
 X-Window-Icon-Dimmed=qgn_list_browser
 X-Osso-Service=osso_browser
 X-HildonDesk-ShowInToolbar=true
 X-Osso-Type=application/x-executable
 MimeType=text/html;text/css;text/sgml;text/x-dtd;application/x-javascript;image/gif;image/jpeg;image/png;image/vnd.wap.wbmp;image/pjpeg;image/bmp;image/x-windows-bmp;image/x-ms-bmp;image/xbm;image/ico;image/x-ico;image/x-xbitmap;text/plain;application/x-shockwave-flash;
 X-Osso-URI-Actions=http;https;ftp;file;

 [X-Osso-URI-Action Handler http]
 Method=load_url
 Name=uri_link_open_link
 TranslationDomain=osso-uri

 [X-Osso-URI-Action Handler https]
 Method=load_url
 Name=uri_link_open_link
 TranslationDomain=osso-uri

 [X-Osso-URI-Action Handler ftp]
 Method=load_url
 Name=uri_link_open_link
 TranslationDomain=osso-uri

 [X-Osso-URI-Action Handler file]
 Method=load_url
 Name=uri_link_open_link
 TranslationDomain=osso-uri

New format browser desktop file (with new "neutral" and "fallback" features):

 [Desktop Entry]
 Encoding=UTF-8
 Version=0.1
 Type=Application
 Name=weba_ap_web_browser
 Comment=weba_ap_web_browser_thumb
 Exec=/usr/bin/browser
 Icon=general_web
 X-Window-Icon=general_web
 X-Window-Icon-Dimmed=general_web
 X-Osso-Service=osso_browser
 X-HildonDesk-ShowInToolbar=true
 X-Osso-Type=application/x-executable
 MimeType=text/html;text/css;text/sgml;text/x-dtd;application/x-javascript;image/gif;image/jpeg;image/png;image/vnd.wap.wbmp;image/pjpeg;image/bmp;image/x-windows-bmp;image/x-ms-bmp;image/xbm;image/ico;image/x-ico;image/x-xbitmap;text/plain;application/x-shockwave-flash;

 [X-Osso-URI-Actions]
 http=X-Osso-URI-Action-Open;X-Osso-URI-Action-Save;X-Osso-URI-Action-Fallback
 https=X-Osso-URI-Action-Open;X-Osso-URI-Action-Save;X-Osso-URI-Action-Fallback
 ftp=X-Osso-URI-Action-Open;X-Osso-URI-Action-Save;X-Osso-URI-Action-Fallback
 file=X-Osso-URI-Action-Open;X-Osso-URI-Action-Save;X-Osso-URI-Action-Fallback;

 [X-Osso-URI-Action-Open]
 Method=load_url
 Name=uri_link_open_link
 TranslationDomain=osso-uri

 [X-Osso-URI-Action-Save]
 Type=Neutral
 Method=save_url
 Name=uri_link_save_link
 TranslationDomain=osso-uri

 [X-Osso-URI-Action-Fallback]
 Type=Fallback
 Method=load_url_fallback
 Name=uri_link_open_link_fallback
 TranslationDomain=osso-uri

Old format media player desktop file:

 [Desktop Entry]
 Encoding=UTF-8
 Version=1.0
 Type=Application
 Name=medi_ap_mediaplayer_name
 Exec=/usr/bin/mediaplayer-ui
 Icon=qgn_list_medi
 X-Icon-path=/usr/share/pixmaps/
 X-Window-Icon=tn-bookmarks-link
 X-Window-Icon-Dimmed=tn-bookmarks-link-dimmed
 X-HildonDesk-ShowInToolbar=true
 X-Osso-Service=mediaplayer
 X-Osso-Type=application/x-executable
 X-Osso-URI-Actions=rtsp
 MimeType=video/x-msvideo;audio/x-mp3;video/mpeg;audio/x-wav;audio/x-real;video/x-real;audio/x-m4a;audio/x-amr;video/x-mp4;video/3gpp;audio/x-mp2;audio/x-ms-wma;audio/x-mpegurl;audio/x-scpls;audio/x-pn-realaudio;audio/x-pn-realaudio-plugin;video/x-ms-asf;audio/x-ms-wax;video/x-ms-wvx;application/vnd.ms-wpl;audio/mp3;video/avi;audio/wav;audio/mpeg;
 Comment=medi_ap_mediaplayer_name_thumb

 [X-Osso-URI-Action Handler rtsp]
 Method=mime_open
 Name=medi_ap_mediaplayer_name
 TranslationDomain=mediaplayer

New format media player desktop file:

 [Desktop Entry]
 Encoding=UTF-8
 Version=1.0
 Type=Application
 Name=medi_ap_mediaplayer_name
 Exec=/usr/bin/mediaplayer-ui
 Icon=tasklaunch_media_player
 X-Icon-path=/usr/share/pixmaps/
 X-Window-Icon=tn-bookmarks-link
 X-Window-Icon-Dimmed=tn-bookmarks-link-dimmed
 X-HildonDesk-ShowInToolbar=true
 X-Osso-Service=mediaplayer
 X-Osso-Type=application/x-executable
 MimeType=video/x-msvideo;audio/x-mp3;video/mpeg;audio/x-wav;audio/x-real;video/x-real;audio/x-m4a;audio/x-amr;video/x-mp4;video/3gpp;audio/x-mp2;audio/x-ms-wma;audio/x-mpegurl;audio/x-scpls;audio/x-pn-realaudio;audio/x-pn-realaudio-plugin;video/x-ms-asf;audio/x-ms-wax;video/x-ms-wvx;application/vnd.ms-wpl;audio/mp3;video/avi;audio/wav;audio/mpeg;
 Comment=medi_ap_mediaplayer_name_thumb

 [X-Osso-URI-Actions]
 rtsp=X-Osso-URI-Action-Open;

 [X-Osso-URI-Action-Open]
 Method=mime_open
 Name=medi_ap_mediaplayer_name
 TranslationDomain=mediaplayer

Implementation details

The schemeinfo.cache file that is a cache for faster lookups, remains unchanged from the old revision. It is used to make scheme->desktop file lookups.