This section describes how to publish Direct messages using the Solace messaging APIs.
Direct Messaging, also known as Reliable Messaging, allows a client to use a Publish and Subscribe (Pub/Sub) messaging model to publish messages.
Direct messages are published to a Topic destination and are routed to receiving clients with matching Topic subscriptions.
Direct messages differ from Guaranteed messages in that:
- They are not retained for a client when that client is not connected to an event broker.
- They can be discarded when congestion or system failures are encountered.
- They are not acknowledged upon delivery.
The following figure shows the process of publishing and receiving Direct messages.
Related Event Broker Provisioning and Configuration Information
To allow clients to publish messages to topics (or to only a specific set of topics) within the Message VPN they are connected, they must be assigned ACLs with the appropriate access controls. For information on how to configure ACLs on event brokers, refer to Management & Shell Users.