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2.4 Detecting object paths and interfaces.

The first elements, to be introspected for a D-Bus object, are further object paths and interfaces.

— Function: dbus-introspect-get-node-names bus service path

All node names of service in D-Bus bus at object path path are returned as list of strings. Example:

          (dbus-introspect-get-node-names
            :session "org.gnome.seahorse" "/org/gnome/seahorse")
          
          ⇒ ("crypto" "keys")

The node names stand for further object paths of the D-Bus service, relative to path. In the example, ‘/org/gnome/seahorse/crypto’ and ‘/org/gnome/seahorse/keys’ are also object paths of the D-Bus service ‘org.gnome.seahorse’.

— Function: dbus-introspect-get-all-nodes bus service path

This function returns all node names of service in D-Bus bus at object path path. It returns a list of strings with all object paths of service, starting at path. Example:

          (dbus-introspect-get-all-nodes :session "org.gnome.seahorse" "/")
          
          ⇒ ("/" "/org" "/org/gnome" "/org/gnome/seahorse"
              "/org/gnome/seahorse/crypto"
              "/org/gnome/seahorse/keys"
              "/org/gnome/seahorse/keys/openpgp"
              "/org/gnome/seahorse/keys/openpgp/local"
              "/org/gnome/seahorse/keys/openssh"
              "/org/gnome/seahorse/keys/openssh/local")
— Function: dbus-introspect-get-interface-names bus service path

There will be returned a list strings of all interface names of service in D-Bus bus at object path path. This list will contain the default interface ‘org.freedesktop.DBus.Introspectable’.

Another default interface is ‘org.freedesktop.DBus.Properties’. If present, interface elements can also have property children. Example:

          (dbus-introspect-get-interface-names
            :system "org.freedesktop.Hal"
            "/org/freedesktop/Hal/devices/computer")
          
          ⇒ ("org.freedesktop.DBus.Introspectable"
              "org.freedesktop.Hal.Device"
              "org.freedesktop.Hal.Device.SystemPowerManagement"
              "org.freedesktop.Hal.Device.CPUFreq")
— Function: dbus-introspect-get-interface bus service path interface

Return interface of service in D-Bus bus at object path path. The return value is an XML element. interface must be a string, element of the list returned by dbus-introspect-get-interface-names. Example:

          (dbus-introspect-get-interface
            :session "org.freedesktop.xesam.searcher"
            "/org/freedesktop/xesam/searcher/main"
            "org.freedesktop.xesam.Search")
          
          ⇒ (interface ((name . "org.freedesktop.xesam.Search"))
               (method ((name . "GetHitData"))
                 (arg ((name . "search") (type . "s") (direction . "in")))
                 (arg ((name . "hit_ids") (type . "au") (direction . "in")))
                 (arg ((name . "fields") (type . "as") (direction . "in")))
                 (arg ((name . "hit_data") (type . "aav") (direction . "out")))
               )
               ...
               (signal ((name . "HitsAdded"))
                 (arg ((name . "search") (type . "s")))
                 (arg ((name . "count") (type . "u")))
               )
             )

With these functions, it is possible to retrieve all introspection data from a running system:

     (with-current-buffer (switch-to-buffer "*introspect*")
       (erase-buffer)
       (dolist (service (dbus-list-known-names :session))
         (dolist (path (dbus-introspect-get-all-nodes :session service "/"))
           ;; We want to introspect only elements, which have more than
           ;; the default interface "org.freedesktop.DBus.Introspectable".
           (when (delete
                  "org.freedesktop.DBus.Introspectable"
                  (dbus-introspect-get-interface-names :session service path))
             (insert (message "\nservice: \"%s\" path: \"%s\"\n" service path)
                     (dbus-introspect :session service path))
             (redisplay t)))))