QtDbus Intro¶

Follow along

http://developer.nokia.com/Community/Wiki/QtDbus_quick_tutorial

In short¶

simon:qtdbus blyth$ ./qdbusxml2cpp.sh
qdbusxml2cpp -v -c DemoIf -p demoif.h:demoif.cpp com.nokia.Demo.xml
Warning: deprecated annotation 'com.trolltech.QtDBus.QtTypeName.In1' found; suggest updating to 'org.qtproject.QtDBus.QtTypeName.In1'
qdbusxml2cpp -v -c DemoIfAdaptor -a demoifadaptor.h:demoifadaptor.cpp com.nokia.Demo.xml
Warning: deprecated annotation 'com.trolltech.QtDBus.QtTypeName.In1' found; suggest updating to 'org.qtproject.QtDBus.QtTypeName.In1'
Warning: deprecated annotation 'com.trolltech.QtDBus.QtTypeName.In1' found; suggest updating to 'org.qtproject.QtDBus.QtTypeName.In1'
Warning: deprecated annotation 'com.trolltech.QtDBus.QtTypeName.In1' found; suggest updating to 'org.qtproject.QtDBus.QtTypeName.In1'
simon:qtdbus blyth$
simon:qtdbus blyth$ qmake
Project MESSAGE: qtAddLibrary: found framework QtDBus in directory /opt/local/Library/Frameworks
Project MESSAGE: qtAddLibrary: found framework QtGui in directory /opt/local/Library/Frameworks
Project MESSAGE: qtAddLibrary: found framework QtCore in directory /opt/local/Library/Frameworks
simon:qtdbus blyth$ make
...
simon:qtdbus blyth$ qtdbus.app/Contents/MacOS/qtdbus      ## dbus daemon needs to be running before starting the app
MyDemo::MyDemo

Interface description XML¶

<node>
  <interface name="com.nokia.Demo">
    <method name="SayHello">
      <annotation name="com.trolltech.QtDBus.QtTypeName.In1" value="QVariantMap"/>
      <arg name="name" type="s" direction="in" />
      <arg name="customdata" type="a{sv}" direction="in" />
    </method>
    <method name="SayHelloThere">
      <arg name="name" type="s" direction="in" />
    </method>
    <method name="SayBye"/>
    <signal name="LateEvent">
        <arg name="eventkind" type="s" direction="out"/>
    </signal>
 </interface>
</node>

Generate code from description with qtdbusxml2cpp¶

simon:qtdbus blyth$ qdbusxml2cpp -h
Usage: qdbusxml2cpp [options...] [xml-or-xml-file] [interfaces...]
Produces the C++ code to implement the interfaces defined in the input file.

Options:
  -a <filename>    Write the adaptor code to <filename>
  -c <classname>   Use <classname> as the class name for the generated classes
  -h               Show this information
  -i <filename>    Add #include to the output
  -l <classname>   When generating an adaptor, use <classname> as the parent class
  -m               Generate #include "filename.moc" statements in the .cpp files
  -N               Don't use namespaces
  -p <filename>    Write the proxy code to <filename>
  -v               Be verbose.
  -V               Show the program version and quit.

If the file name given to the options -a and -p does not end in .cpp or .h, the
program will automatically append the suffixes and produce both files.
You can also use a colon (:) to separate the header name from the source file
name, as in '-a filename_p.h:filename.cpp'.

If you pass a dash (-) as the argument to either -p or -a, the output is written
to the standard output

Generate Client Proxy Code from XML¶

simon:qtdbus blyth$ pwd
/Users/blyth/e/ui/qt/qtdbus
simon:qtdbus blyth$ vi com.nokia.Demo.xml
simon:qtdbus blyth$ which qdbusxml2cpp
/opt/local/bin/qdbusxml2cpp
simon:qtdbus blyth$ qdbusxml2cpp -v -c DemoIf -p demoif.h:demoif.cpp com.nokia.Demo.xml
                    ##
                    ##  -v verbose
                    ##  -c DemoIf                    the classname to use
                    ##  -p demoif.h:demoif.cpp       write proxy code to these files
                    ##
                    ##   generates demoif.{h,cpp}

Warning: deprecated annotation 'com.trolltech.QtDBus.QtTypeName.In1' found; suggest updating to 'org.qtproject.QtDBus.QtTypeName.In1'
simon:qtdbus blyth$ ll
total 32
drwxr-xr-x  3 blyth  staff   102 27 Nov 12:42 ..
-rw-r--r--  1 blyth  staff    95 27 Nov 12:42 qtdbus_intro.rst
-rw-r--r--  1 blyth  staff   430 27 Nov 12:43 com.nokia.Demo.xml
-rw-r--r--  1 blyth  staff  1592 27 Nov 12:44 demoif.h
-rw-r--r--  1 blyth  staff   666 27 Nov 12:44 demoif.cpp
drwxr-xr-x  6 blyth  staff   204 27 Nov 12:44 .
simon:qtdbus blyth$

https://bugreports.qt-project.org/browse/QTBUG-14835

Attempt to follow the suggestion in the deprecatin warning, gives error and fails to generate, so live with the warning:

perl -pi -e 's,trolltech,qtproject,g' com.nokia.Demo.xml

simon:qtdbus blyth$ qdbusxml2cpp -v -c DemoIf -p demoif.h:demoif.cpp com.nokia.Demo.xml
Got unknown type `a{sv}'
You should add <annotation name="org.qtproject.QtDBus.QtTypeName.In1" value="<type>"/> to the XML description

simon:qtdbus blyth$ perl -pi -e 's,qtproject,trolltech,g' com.nokia.Demo.xml    ## back to original
simon:qtdbus blyth$ qdbusxml2cpp -v -c DemoIf -p demoif.h:demoif.cpp com.nokia.Demo.xml
Warning: deprecated annotation 'com.trolltech.QtDBus.QtTypeName.In1' found; suggest updating to 'org.qtproject.QtDBus.QtTypeName.In1'

http://dbus.freedesktop.org/doc/dbus-specification.html

Generate Server Stub (Adapter code) from XML¶

Note -a rather than -p:

simon:qtdbus blyth$ qdbusxml2cpp -v -c DemoIfAdaptor -a demoifadaptor.h:demoifadaptor.cpp com.nokia.Demo.xml
Warning: deprecated annotation 'com.trolltech.QtDBus.QtTypeName.In1' found; suggest updating to 'org.qtproject.QtDBus.QtTypeName.In1'
Warning: deprecated annotation 'com.trolltech.QtDBus.QtTypeName.In1' found; suggest updating to 'org.qtproject.QtDBus.QtTypeName.In1'
Warning: deprecated annotation 'com.trolltech.QtDBus.QtTypeName.In1' found; suggest updating to 'org.qtproject.QtDBus.QtTypeName.In1'
simon:qtdbus blyth$

Put the above in a script¶

#!/bin/bash -l

generate(){
   local xml=com.nokia.Demo.xml
   local cls=DemoIf
   local nam=$(echo $cls | tr '[A-Z]' '[a-z]')
   local pcmd="qdbusxml2cpp -v -c $cls -p $nam.h:$nam.cpp $xml"
   echo $pcmd
   eval $pcmd
   local acmd="qdbusxml2cpp -v -c ${cls}Adaptor -a ${nam}adaptor.h:${nam}adaptor.cpp $xml"
   echo $acmd
   eval $acmd
}

generate $*

Make a project¶

simon:qtdbus blyth$ qmake -project

Add to the qtdbus.pro generated:

QT += dbus

Then:

qmake to generate a Makefile
make succeeds to moc the signal/slots and compile all the generated code by complains of lack of main at linking.

Run¶

simon:qtdbus blyth$ qtdbus.app/Contents/MacOS/qtdbus
MyDemo::MyDemo
Dynamic session lookup supported but failed: launchd did not provide a socket path, verify that org.freedesktop.dbus-session.plist is loaded!

Try to query server¶

simon:~ blyth$ which qdbus
/opt/local/bin/qdbus

simon:~ blyth$ qdbus com.nokia.Demo
Dynamic session lookup supported but failed: launchd did not provide a socket path, verify that org.freedesktop.dbus-session.plist is loaded!
Could not connect to D-Bus server: org.freedesktop.DBus.Error.NoMemory: Not enough memory

qdbus probing¶

simon:~ blyth$ which dbus-send
/opt/local/bin/dbus-send

simon:~ blyth$ which qdbus
/opt/local/bin/qdbus

When dbus daemon is not running:

simon:~ blyth$ qdbus com.nokia.Demo
Dynamic session lookup supported but failed: launchd did not provide a socket path, verify that org.freedesktop.dbus-session.plist is loaded!
Could not connect to D-Bus server: org.freedesktop.DBus.Error.NoMemory: Not enough memory

When running:

simon:~ blyth$ qdbus com.nokia.Demo
/

The daemon knows about the interface:

simon:~ blyth$ qdbus com.nokia.Demo /
signal void com.nokia.Demo.LateEvent(QString eventkind)
method void com.nokia.Demo.SayBye()
method void com.nokia.Demo.SayHello(QString name, QVariantMap customdata)
method QDBusVariant org.freedesktop.DBus.Properties.Get(QString interface_name, QString property_name)
method QVariantMap org.freedesktop.DBus.Properties.GetAll(QString interface_name)
method void org.freedesktop.DBus.Properties.Set(QString interface_name, QString property_name, QDBusVariant value)
method QString org.freedesktop.DBus.Introspectable.Introspect()
method QString org.freedesktop.DBus.Peer.GetMachineId()
method void org.freedesktop.DBus.Peer.Ping()

simon:~ blyth$ dbus-send --type=method_call --print-reply \
>     --dest=com.nokia.Demo / org.freedesktop.DBus.Introspectable.Introspect
method return sender=:1.0 -> dest=:1.3 reply_serial=2
   string "<!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
"http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
<node>
  <interface name="com.nokia.Demo">
    <method name="SayHello">
      <annotation value="QVariantMap" name="com.trolltech.QtDBus.QtTypeName.In1"/>
      <arg direction="in" type="s" name="name"/>
      <arg direction="in" type="a{sv}" name="customdata"/>
    </method>
    <method name="SayBye"/>
    <signal name="LateEvent">
      <arg direction="out" type="s" name="eventkind"/>
    </signal>
  </interface>
  <interface name="org.freedesktop.DBus.Properties">
    <method name="Get">
      <arg name="interface_name" type="s" direction="in"/>
      <arg name="property_name" type="s" direction="in"/>
      <arg name="value" type="v" direction="out"/>
    </method>
    <method name="Set">
      <arg name="interface_name" type="s" direction="in"/>
      <arg name="property_name" type="s" direction="in"/>
      <arg name="value" type="v" direction="in"/>
    </method>
    <method name="GetAll">
      <arg name="interface_name" type="s" direction="in"/>
      <arg name="values" type="a{sv}" direction="out"/>
      <annotation name="org.qtproject.QtDBus.QtTypeName.Out0" value="QVariantMap"/>
    </method>
  </interface>
  <interface name="org.freedesktop.DBus.Introspectable">
    <method name="Introspect">
      <arg name="xml_data" type="s" direction="out"/>
    </method>
  </interface>
  <interface name="org.freedesktop.DBus.Peer">
    <method name="Ping"/>
    <method name="GetMachineId">
      <arg name="machine_uuid" type="s" direction="out"/>
    </method>
  </interface>
</node>
"

Remote signalling:

simon:~ blyth$ qdbus com.nokia.Demo / com.nokia.Demo.SayBye

Over at the app console:

simon:qtdbus blyth$ qtdbus.app/Contents/MacOS/qtdbus
MyDemo::MyDemo
MyDemo::SayBye

Similarly:

simon:~ blyth$ dbus-send --type=method_call --print-reply \
>     --dest=com.nokia.Demo / com.nokia.Demo.SayBye
method return sender=:1.0 -> dest=:1.5 reply_serial=2

What about methods with parameters:

simon:~ blyth$ qdbus com.nokia.Demo / com.nokia.Demo.SayHello simon
Invalid number of parameters
simon:~ blyth$ qdbus com.nokia.Demo / com.nokia.Demo.SayHello
Error: org.freedesktop.DBus.Error.UnknownMethod
No such method 'SayHello' in interface 'com.nokia.Demo' at object path '/' (signature '')
simon:~ blyth$
simon:~ blyth$ qdbus com.nokia.Demo / com.nokia.Demo.SayHello simon b
Sorry, can't pass arg of type 'QVariantMap'.

http://forum.kde.org/viewtopic.php?f=17&t=85292

Seems cannot do that from commandline arguments with qdbus tool. So..

Add method that just takes string arg for simplicity¶

Succeeds to invoke methods with string arguments in the running qt app:

simon:~ blyth$ qdbus com.nokia.Demo / com.nokia.Demo.SayHelloThere simon
simon:~ blyth$ qdbus com.nokia.Demo / com.nokia.Demo.SayHelloThere "http://simon?c=2,3,4&other=yes&yo"

simon:qtdbus blyth$ ./run.sh
MyDemo::MyDemo
MyDemo::SayHelloThere [ "simon" ]
MyDemo::SayHelloThere [ "http://simon?c=2,3,4&other=yes&yo" ]

Python dbus¶

For passing dicts need to go beyond qdbus:

simon:~ blyth$ sudo port install -v dbus-python26
Password:
--->  Computing dependencies for gettext

Too many dependencies¶

simon:~ blyth$ port deps dbus-python26
Full Name: dbus-python26 @0.83.2_0
Build Dependencies:   pkgconfig
Library Dependencies: dbus, dbus-glib, gettext, glib2, libiconv, python26, py26-gobject
simon:~ blyth$

Links

Content Skeleton

This Page

Previous topic

Next topic

QtDbus Intro¶

In short¶

Interface description XML¶

Generate code from description with qtdbusxml2cpp¶

Generate Client Proxy Code from XML¶

Generate Server Stub (Adapter code) from XML¶

Put the above in a script¶

Make a project¶

Run¶

Try to query server¶

qdbus probing¶

Add method that just takes string arg for simplicity¶

Python dbus¶

Too many dependencies¶

Navigation

Quick search

Links

Content Skeleton

This Page

Previous topic

Next topic

QtDbus Intro¶

In short¶

Interface description XML¶

Generate code from description with qtdbusxml2cpp¶

Generate Client Proxy Code from XML¶

Generate Server Stub (Adapter code) from XML¶

Put the above in a script¶

Make a project¶

Run¶

Try to query server¶

qdbus probing¶

Add method that just takes string arg for simplicity¶

Python dbus¶

Too many dependencies¶

Navigation