Example 3: Connections to Remote Nodes using a Registry#
Describes how the Qt Remote Objects registry establishes connections between nodes. .. _qtro-example3: This example illustrates the use of a Registry to build the node topology. For simple networks, we use a
QUrl to create a direct connection between two nodes. For complex networks, we use a registry, where you use a different
QUrl to point both the host and replica nodes to the registry. For only two nodes, the benefits of using a registry are minimal. But, as the network grows, using a registry means that all nodes only need to connect to the registry via a single
QUrl . In comparison, with direct connections, nodes would have to maintain a list of QUrls for every single node that they link to.
Set up the Source#
simpleswitch.cpp sources from Example can be used without modification. The difference is in the way a host node is created and connected to the registry:
from PySide6.QtCore import QCoreApplication from simpleswitch import * if __name__ == "__main__": a = QCoreApplication(argc, argv) srcSwitch = SimpleSwitch() regNode = QRemoteObjectRegistryHost(QUrl(QStringLiteral("local:registry"))) srcNode = QRemoteObjectHost(QUrl(QStringLiteral("local:switch")), QUrl(QStringLiteral("local:registry"))) #Note, you can add srcSwitch directly to regNode if desired. #We use two Nodes here, as the regNode could easily be in a third process. srcNode.enableRemoting(srcSwitch) # enable remoting of source object return a.exec()
Set up the Replica#
The requestor object used for this example is the dynamic replica client discussed in Example 2 .
The only modification is in
main.cpp: a Registry node is created to acquire a Replica :
repNode = QRemoteObjectNode(QUrl(QStringLiteral("local:registry")))
When run together with the source-side example, the output is identical to Example 1 .