Struct Pubsub 

pub struct Pubsub<T: PubsubTopic, P: Clone> { /* private fields */ }

A publish-subscribe system that allows multiple subscribers to receive messages published to specific topics.

The Pubsub struct is the main interface for creating topics, publishing messages, and managing subscriptions. It uses an internal Arc reference to shared state, allowing multiple clones of the Pubsub instance to share the same underlying subscription data.

Type Parameters

• T - The topic type, must implement PubsubTopic (Clone + Hash + Eq)
• P - The payload type, must implement Clone

Examples

// let pubsub = Pubsub::new();
// let subscriber = pubsub.subscribe(vec!["topic1", "topic2"]).await;
// pubsub.publish("topic1", "Hello, world!".to_owned()).await;

Implementations

impl<T: PubsubTopic, P: Clone> Pubsub<T, P>

pub fn new() -> Self

Creates a new Pubsub instance with empty topic subscriptions.

This initializes the internal shared state and returns a new Pubsub instance that can be used to manage topics and subscriptions.

Examples

// let pubsub = Pubsub::new();

pub async fn subscribe(&self, topics: Vec<T>) -> Subscriber<T, P>

Subscribes to one or more topics and returns a new Subscriber instance.

Arguments

• topics - A vector of topics to subscribe to. The subscriber will receive messages published to any of these topics.

Returns

A new Subscriber instance that can be used to receive messages for the subscribed topics.

Example

// let pubsub = Pubsub::new();
// let subscriber = pubsub.subscribe(vec!["topic1", "topic2"]).await;

pub async fn publish(&self, topic: T, payload: P)

Publishes a message to a specific topic.

Arguments

• topic - The topic to publish the message to. Subscribers subscribed to this topic will receive the message.
• payload - The message payload to send to subscribers.

Example

// let pubsub = Pubsub::new();
// pubsub.publish("topic1", "Hello, world!".to_owned()).await;

Trait Implementations

impl<T: Clone + PubsubTopic, P: Clone + Clone> Clone for Pubsub<T, P>

fn clone(&self) -> Pubsub<T, P>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: PubsubTopic, P: Clone> Drop for Pubsub<T, P>

Implements the Drop trait for Pubsub to ensure proper cleanup when the last instance is dropped.

When the last strong reference to the Pubsub’s inner data is dropped, this implementation:

1. Checks if this is the last strong reference (Arc::strong_count == 1)
2. If so, iterates through all topics and their subscribers
3. Closes each subscriber’s channel to prevent them from being stuck waiting for messages

This ensures that any remaining subscribers will receive an error on their next recv() call rather than blocking indefinitely, allowing them to clean up their resources properly.

fn drop(&mut self)

Executes the destructor for this type.