class QDBusMessage#

The QDBusMessage class represents one message sent or received over the D-Bus bus. More…

Synopsis#

Methods#

Static functions#

Note

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Detailed Description#

This object can represent any of the four different types of messages ( MessageType ) that can occur on the bus:

  • Method calls

  • Method return values

  • Signal emissions

  • Error codes

Objects of this type are created with the static createError() , createMethodCall() and createSignal() functions. Use the send() function to send the messages.

class MessageType#

The possible message types:

Constant

Description

QDBusMessage.MethodCallMessage

a message representing an outgoing or incoming method call

QDBusMessage.SignalMessage

a message representing an outgoing or incoming signal emission

QDBusMessage.ReplyMessage

a message representing the return values of a method call

QDBusMessage.ErrorMessage

a message representing an error condition in response to a method call

QDBusMessage.InvalidMessage

an invalid message: this is never set on messages received from D-Bus
__init__(other)#
Parameters:

other – QDBusMessage

Constructs a copy of the object given by other.

Note: QDBusMessage objects are shared. Modifications made to the copy will affect the original one as well. See setDelayedReply() for more information.

__init__()

Constructs an empty, invalid QDBusMessage object.

arguments()#
Return type:

.list of QVariant

Returns the list of arguments that are going to be sent or were received from D-Bus.

See also

setArguments()

autoStartService()#
Return type:

bool

Returns the auto start flag, as set by setAutoStartService() . By default, this flag is true, which means Qt D-Bus will auto start a service, if it is not running already.

static createError(type, msg)#
Parameters:
Return type:

QDBusMessage

Constructs a new DBus message for the error type type using the message msg. Returns the DBus message.

static createError(err)
Parameters:

err – QDBusError

Return type:

QDBusMessage

Constructs a new DBus message representing the given error.

static createError(name, msg)
Parameters:

  • name – str

  • msg – str

Return type:

QDBusMessage

Constructs a new DBus message representing an error, with the given name and msg.

createErrorReply(type, msg)#
Parameters:
Return type:

QDBusMessage

Constructs a new DBus reply message for the error type type using the message msg. Returns the DBus message.

createErrorReply(err)
Parameters:

err – QDBusError

Return type:

QDBusMessage

Constructs a new DBus message representing an error reply message, from the given error object.

createErrorReply(name, msg)
Parameters:

  • name – str

  • msg – str

Return type:

QDBusMessage

Constructs a new DBus message representing an error reply message, with the given name and msg.

static createMethodCall(destination, path, interface, method)#
Parameters:

  • destination – str

  • path – str

  • interface – str

  • method – str

Return type:

QDBusMessage

Constructs a new DBus message representing a method call. A method call always informs its destination address (service, path, interface and method).

The DBus bus allows calling a method on a given remote object without specifying the destination interface, if the method name is unique. However, if two interfaces on the remote object export the same method name, the result is undefined (one of the two may be called or an error may be returned).

When using DBus in a peer-to-peer context (i.e., not on a bus), the service parameter is optional.

The QDBusInterface class provides a simpler abstraction to synchronous method calling.

This function returns a QDBusMessage object that can be sent with call() .

createReply([arguments=list()])#
Parameters:

arguments – .list of QVariant

Return type:

QDBusMessage

Constructs a new DBus message representing a reply, with the given arguments.

createReply(argument)
Parameters:

argument – object

Return type:

QDBusMessage

Constructs a new DBus message representing a reply, with the given argument.

static createSignal(path, interface, name)#
Parameters:

  • path – str

  • interface – str

  • name – str

Return type:

QDBusMessage

Constructs a new DBus message with the given path, interface and name, representing a signal emission.

A DBus signal is emitted from one application and is received by all applications that are listening for that signal from that interface.

The QDBusMessage object that is returned can be sent using the send() function.

static createTargetedSignal(service, path, interface, name)#
Parameters:

  • service – str

  • path – str

  • interface – str

  • name – str

Return type:

QDBusMessage

Constructs a new DBus message with the given path, interface and name, representing a signal emission to a specific destination.

A DBus signal is emitted from one application and is received only by the application owning the destination service name.

The QDBusMessage object that is returned can be sent using the send() function.

errorMessage()#
Return type:

str

Returns the human-readable message associated with the error that was received.

errorName()#
Return type:

str

Returns the name of the error that was received.

interface()#
Return type:

str

Returns the interface of the method being called (in the case of a method call) or of the signal being received from.

isDelayedReply()#
Return type:

bool

Returns the delayed reply flag, as set by setDelayedReply() . By default, this flag is false, which means Qt D-Bus will generate automatic replies when necessary.

isInteractiveAuthorizationAllowed()#
Return type:

bool

Returns whether the message has the ALLOW_INTERACTIVE_AUTHORIZATION flag set.

isReplyRequired()#
Return type:

bool

Returns the flag that indicates if this message should see a reply or not. This is only meaningful for method call messages : any other kind of message cannot have replies and this function will always return false for them.

member()#
Return type:

str

Returns the name of the signal that was emitted or the name of the method that was called.

__lshift__(arg)#
Parameters:

arg – object

Return type:

QDBusMessage

Appends the argument arg to the list of arguments to be sent over D-Bus in a method call or signal emission.

path()#
Return type:

str

Returns the path of the object that this message is being sent to (in the case of a method call) or being received from (for a signal).

service()#
Return type:

str

Returns the name of the service or the bus address of the remote method call.

setArguments(arguments)#
Parameters:

arguments – .list of QVariant

Sets the arguments that are going to be sent over D-Bus to arguments. Those will be the arguments to a method call or the parameters in the signal.

See also

arguments()

setAutoStartService(enable)#
Parameters:

enable – bool

Sets the auto start flag to enable. This flag only makes sense for method call messages, where it tells the D-Bus server to either auto start the service responsible for the service name, or not to auto start it.

By default this flag is true, i.e. a service is autostarted. This means:

When the service that this method call is sent to is already running, the method call is sent to it. If the service is not running yet, the D-Bus daemon is requested to autostart the service that is assigned to this service name. This is handled by .service files that are placed in a directory known to the D-Bus server. These files then each contain a service name and the path to a program that should be executed when this service name is requested.

setDelayedReply(enable)#
Parameters:

enable – bool

Sets whether the message will be replied later (if enable is true) or if an automatic reply should be generated by Qt D-Bus (if enable is false).

In D-Bus, all method calls must generate a reply to the caller, unless the caller explicitly indicates otherwise (see isReplyRequired() ). QtDBus automatically generates such replies for any slots being called, but it also allows slots to indicate whether they will take responsibility of sending the reply at a later time, after the function has finished processing.

setInteractiveAuthorizationAllowed(enable)#
Parameters:

enable – bool

Enables or disables the ALLOW_INTERACTIVE_AUTHORIZATION flag in a message.

This flag only makes sense for method call messages ( MethodCallMessage ). If enable is set to true, the flag indicates to the callee that the caller of the method is prepared to wait for interactive authorization to take place (for instance via Polkit) before the actual method is processed.

If enable is set to false, the flag is not set, meaning that the other end is expected to make any authorization decisions non-interactively and promptly. This is the default.

The org.freedesktop.DBus.Error.InteractiveAuthorizationRequired error indicates that authorization failed, but could have succeeded if this flag had been set.

signature()#
Return type:

str

Returns the signature of the signal that was received or for the output arguments of a method call.

swap(other)#
Parameters:

other – QDBusMessage

Swaps this QDBusMessage instance with other.

type()#
Return type:

MessageType

Returns the message type.