General

Cross-cutting programming concerns that apply to both RPC and Pub/Sub: the URI syntax Bondy accepts, and the session lifecycle events every client can observe. For RPC- and PubSub-specific practical patterns, see Remote Procedure Calls and Publish and Subscribe; for how to design good URIs rather than just valid ones, see Naming Best Practices.

URI Format

A procedure or topic URI is a sequence of dot-separated components, e.g. com.example.orders.create. Bondy validates every URI against one of two rule sets, set node-wide with wamp.uri.strictness:

• loose (the default) — a component may contain any character except whitespace, ., #, and control characters.
• strict — a component is restricted to lowercase letters, digits, and underscore ([0-9a-z_]).

Registering or subscribing with a prefix or wildcard match policy relaxes this further: a wildcard subscription's empty components (com..created, matching com.orders.created and com.users.created alike) are only valid because the match policy explicitly allows empty segments — an exact-match URI never has one.

Session Meta Events and Procedures

Every session's lifecycle is observable by any other session on the same realm, and a session can retrieve its own or another session's details on demand — see the Session WAMP API Reference for the full contract. In practice:

Python

# Observe sessions joining and leaving the realm
await self._session.subscribe(self.on_session_join, "wamp.session.on_join")
await self._session.subscribe(self.on_session_leave, "wamp.session.on_leave")

# Bondy also sends the keyword argument session_guid,
# so each handler accepts **kwargs.
def on_session_join(self, session, **kwargs):
    print("Session joined:", session["session"])

def on_session_leave(self, session_id, authid, authrole, **kwargs):
    print("Session left:", session_id, authid, authrole)

# Retrieve this session's own details
own_session = await self._session.call("bondy.session.self")

# Retrieve a specific session by id (routed cluster-wide)
other_session = await self._session.call(
    "wamp.session.get", session_id
)

bondy.session.self is the cheaper call when you only need your own session — it never leaves the node, unlike wamp.session.get, which Bondy routes to whichever node the target session actually lives on.