anycms_event/
event.rs

1//! Core [`Event`] trait definition.
2//!
3//! All events must implement this trait to be publishable on the event bus.
4
5/// Core trait that all events must implement.
6///
7/// Events must be `Clone + Send + Sync + 'static` so they can be type-erased
8/// via `Arc<dyn Any + Send + Sync>` and downcast back to the concrete type
9/// in subscriber handlers.
10///
11/// # Example
12///
13/// ```ignore
14/// #[derive(Clone, Debug)]
15/// struct UserCreated {
16///     user_id: u64,
17///     name: String,
18/// }
19///
20/// impl Event for UserCreated {
21///     fn event_name() -> &'static str { "user.created" }
22///
23///     fn topic() -> &'static str { "user" }
24/// }
25/// ```
26pub trait Event: Clone + Send + Sync + 'static {
27    /// Unique name for this event type, used for routing and topic matching.
28    fn event_name() -> &'static str
29    where
30        Self: Sized;
31
32    /// Topic this event belongs to. Default is the event_name itself.
33    ///
34    /// Override this when multiple event types share a common topic namespace,
35    /// e.g., `"user"` for both `UserCreated` and `UserDeleted`.
36    fn topic() -> &'static str
37    where
38        Self: Sized,
39    {
40        Self::event_name()
41    }
42
43    /// Serialize event to JSON for observers like TriggerRuleEngine.
44    /// Returns `None` by default — events that implement `Serialize` can override
45    /// to provide their JSON representation.
46    fn to_json(&self) -> Option<serde_json::Value> {
47        let _ = self;
48        None
49    }
50
51    /// Deserialize event from a JSON string.
52    ///
53    /// Default returns `None` — events that implement `Deserialize` can override
54    /// to provide deserialization. The `#[derive(Event)]` macro auto-generates
55    /// this using `serde_json::from_str`.
56    fn from_json(json: &str) -> Option<Self>
57    where
58        Self: Sized,
59    {
60        let _ = json;
61        None
62    }
63}
anycms_event/event.rs

anycms_event/
event.rs
