View source for URL Handler/API rev2

This document describes the second revision of the <code>hildon_uri_*</code> API that was added in rev 2. Please see [[URL Handler/API rev1|revision 1 of the API]] for the background and also information about the basic file format used.

Make sure to read the desktop entry [http://standards.freedesktop.org/desktop-entry-spec/latest/ specification].

The utility <code>update-desktop-database</code> 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 <code>uri-default-action.list</code> 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.

[[Category:Development]]