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    Interface PubSub<Events>

    This will be removed from @libp2p/interface in a future release, pubsub implementations should declare their own types

    interface PubSub<Events extends Record<string, any> = PubSubEvents> {
        globalSignaturePolicy: "StrictSign" | "StrictNoSign";
        multicodecs: string[];
        topicValidators: Map<string, TopicValidatorFn>;
        addEventListener<K extends string | number | symbol>(
            type: K,
            listener: null | EventHandler<Events[K]>,
            options?: boolean | AddEventListenerOptions,
        ): void;
        dispatchEvent(event: Event): boolean;
        dispatchEvent(event: Event): boolean;
        getPeers(): PeerId[];
        getSubscribers(topic: string): PeerId[];
        getTopics(): string[];
        listenerCount(type: string): number;
        publish(topic: string, data: Uint8Array): Promise<PublishResult>;
        removeEventListener<K extends string | number | symbol>(
            type: K,
            listener?: null | EventHandler<Events[K]>,
            options?: boolean | EventListenerOptions,
        ): void;
        removeEventListener(
            type: string,
            listener?: EventHandler<Event>,
            options?: boolean | EventListenerOptions,
        ): void;
        safeDispatchEvent<Detail>(
            type: keyof Events,
            detail?: CustomEventInit<Detail>,
        ): boolean;
        subscribe(topic: string): void;
        unsubscribe(topic: string): void;
    }

    Type Parameters

    Hierarchy (View Summary)

    Implemented by

    Index

    Properties

    globalSignaturePolicy multicodecs topicValidators

    Methods

    addEventListener dispatchEvent getPeers getSubscribers getTopics listenerCount publish removeEventListener safeDispatchEvent subscribe unsubscribe

    Properties

    globalSignaturePolicy: "StrictSign" | "StrictNoSign"

    The global signature policy controls whether or not we sill send and receive signed or unsigned messages.

    Signed messages prevent spoofing message senders and should be preferred to using unsigned messages.

    multicodecs: string[]

    A list of multicodecs that contain the pubsub protocol name.

    topicValidators: Map<string, TopicValidatorFn>

    Pubsub routers support message validators per topic, which will validate the message before its propagations. They are stored in a map where keys are the topic name and values are the validators.

    const topic = 'topic'
    const validateMessage = (msgTopic, msg) => {
      const input = uint8ArrayToString(msg.data)
      const validInputs = ['a', 'b', 'c']

      if (!validInputs.includes(input)) {
        throw new Error('no valid input received')
      }
    }
    libp2p.pubsub.topicValidators.set(topic, validateMessage)

    Methods

    • Appends an event listener for events whose type attribute value is type. The callback argument sets the callback that will be invoked when the event is dispatched.

      The options argument sets listener-specific options. For compatibility this can be a boolean, in which case the method behaves exactly as if the value was specified as options's capture.

      When set to true, options's capture prevents callback from being invoked when the event's eventPhase attribute value is BUBBLING_PHASE. When false (or not present), callback will not be invoked when event's eventPhase attribute value is CAPTURING_PHASE. Either way, callback will be invoked if event's eventPhase attribute value is AT_TARGET.

      When set to true, options's passive indicates that the callback will not cancel the event by invoking preventDefault(). This is used to enable performance optimizations described in § 2.8 Observing event listeners.

      When set to true, options's once indicates that the callback will only be invoked once after which the event listener will be removed.

      If an AbortSignal is passed for options's signal, then the event listener will be removed when signal is aborted.

      The event listener is appended to target's event listener list and is not appended if it has the same type, callback, and capture.

      MDN Reference

      Type Parameters

      • K extends string | number | symbol

      Parameters

      Returns void

    • Dispatches a synthetic event event to target and returns true if either event's cancelable attribute value is false or its preventDefault() method was not invoked, and false otherwise.

      MDN Reference

      Parameters

      Returns boolean

    • Dispatches a synthetic event event to target and returns true if either event's cancelable attribute value is false or its preventDefault() method was not invoked, and false otherwise.

      MDN Reference

      Parameters

      Returns boolean

    • Gets a list of the PeerIds that are subscribed to one topic.

      Parameters

      • topic: string

      Returns PeerId[]

      const peerIds = libp2p.pubsub.getSubscribers(topic)

    • Parameters

      • type: string

      Returns number

    • Removes the event listener in target's event listener list with the same type, callback, and options.

      MDN Reference

      Type Parameters

      • K extends string | number | symbol

      Parameters

      • type: K
      • Optionallistener: null | EventHandler<Events[K]>
      • Optionaloptions: boolean | EventListenerOptions

      Returns void

    • Removes the event listener in target's event listener list with the same type, callback, and options.

      MDN Reference

      Parameters

      • type: string
      • Optionallistener: EventHandler<Event>
      • Optionaloptions: boolean | EventListenerOptions

      Returns void

    • Subscribes to a pubsub topic.

      Parameters

      • topic: string

      Returns void

      const topic = 'topic'
      const handler = (msg) => {
        if (msg.topic === topic) {
          // msg.data - pubsub data received
        }
      }

      libp2p.pubsub.addEventListener('message', handler)
      libp2p.pubsub.subscribe(topic)

    • Unsubscribes from a pubsub topic.

      Parameters

      • topic: string

      Returns void

      const topic = 'topic'
      const handler = (msg) => {
        // msg.data - pubsub data received
      }

      libp2p.pubsub.removeEventListener(topic handler)
      libp2p.pubsub.unsubscribe(topic)

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