Trait libp2p_swarm::protocols_handler::ProtocolsHandler

source · [−]
pub trait ProtocolsHandler: Send + 'static {
    type InEvent: Send + 'static;
    type OutEvent: Send + 'static;
    type Error: Error + Send + 'static;
    type InboundProtocol: InboundUpgradeSend;
    type OutboundProtocol: OutboundUpgradeSend;
    type InboundOpenInfo: Send + 'static;
    type OutboundOpenInfo: Send + 'static;

Show 13 methods    fn listen_protocol(
        &self
    ) -> SubstreamProtocol<Self::InboundProtocol, Self::InboundOpenInfo>;

    fn inject_fully_negotiated_inbound(
        &mut self, 
        protocol: <Self::InboundProtocol as InboundUpgradeSend>::Output, 
        info: Self::InboundOpenInfo
    );

    fn inject_fully_negotiated_outbound(
        &mut self, 
        protocol: <Self::OutboundProtocol as OutboundUpgradeSend>::Output, 
        info: Self::OutboundOpenInfo
    );

    fn inject_event(&mut self, event: Self::InEvent);

    fn inject_dial_upgrade_error(
        &mut self, 
        info: Self::OutboundOpenInfo, 
        error: ProtocolsHandlerUpgrErr<<Self::OutboundProtocol as OutboundUpgradeSend>::Error>
    );

    fn connection_keep_alive(&self) -> KeepAlive;

    fn poll(
        &mut self, 
        cx: &mut Context<'_>
    ) -> Poll<ProtocolsHandlerEvent<Self::OutboundProtocol, Self::OutboundOpenInfo, Self::OutEvent, Self::Error>>;

    fn inject_address_change(&mut self, _new_address: &Multiaddr) { ... }

    fn inject_listen_upgrade_error(
        &mut self, 
        _: Self::InboundOpenInfo, 
        _: ProtocolsHandlerUpgrErr<<Self::InboundProtocol as InboundUpgradeSend>::Error>
    ) { ... }

    fn map_in_event<TNewIn, TMap>(
        self, 
        map: TMap
    ) -> MapInEvent<Self, TNewIn, TMap>
    where
        Self: Sized,
        TMap: Fn(&TNewIn) -> Option<&Self::InEvent>,
    { ... }

    fn map_out_event<TMap, TNewOut>(self, map: TMap) -> MapOutEvent<Self, TMap>
    where
        Self: Sized,
        TMap: FnMut(Self::OutEvent) -> TNewOut,
    { ... }

    fn select<TProto2>(
        self, 
        other: TProto2
    ) -> ProtocolsHandlerSelect<Self, TProto2>
    where
        Self: Sized,
    { ... }

    fn into_node_handler_builder(self) -> NodeHandlerWrapperBuilder<Self>
    where
        Self: Sized,
    { ... }

}
Expand description

A handler for a set of protocols used on a connection with a remote.

This trait should be implemented for a type that maintains the state for the execution of a specific protocol with a remote.

Handling a protocol

Communication with a remote over a set of protocols is initiated in one of two ways:

  1. Dialing by initiating a new outbound substream. In order to do so, ProtocolsHandler::poll() must return an ProtocolsHandlerEvent::OutboundSubstreamRequest, providing an instance of libp2p_core::upgrade::OutboundUpgrade that is used to negotiate the protocol(s). Upon success, ProtocolsHandler::inject_fully_negotiated_outbound is called with the final output of the upgrade.

  2. Listening by accepting a new inbound substream. When a new inbound substream is created on a connection, ProtocolsHandler::listen_protocol is called to obtain an instance of libp2p_core::upgrade::InboundUpgrade that is used to negotiate the protocol(s). Upon success, ProtocolsHandler::inject_fully_negotiated_inbound is called with the final output of the upgrade.

Connection Keep-Alive

A ProtocolsHandler can influence the lifetime of the underlying connection through ProtocolsHandler::connection_keep_alive. That is, the protocol implemented by the handler can include conditions for terminating the connection. The lifetime of successfully negotiated substreams is fully controlled by the handler.

Implementors of this trait should keep in mind that the connection can be closed at any time. When a connection is closed gracefully, the substreams used by the handler may still continue reading data until the remote closes its side of the connection.

Associated Types

Custom event that can be received from the outside.

Custom event that can be produced by the handler and that will be returned to the outside.

The type of errors returned by ProtocolsHandler::poll.

The inbound upgrade for the protocol(s) used by the handler.

The outbound upgrade for the protocol(s) used by the handler.

The type of additional information returned from listen_protocol.

The type of additional information passed to an OutboundSubstreamRequest.

Required methods

The InboundUpgrade to apply on inbound substreams to negotiate the desired protocols.

Note: The returned InboundUpgrade should always accept all the generally supported protocols, even if in a specific context a particular one is not supported, (eg. when only allowing one substream at a time for a protocol). This allows a remote to put the list of supported protocols in a cache.

Injects the output of a successful upgrade on a new inbound substream.

Injects the output of a successful upgrade on a new outbound substream.

The second argument is the information that was previously passed to ProtocolsHandlerEvent::OutboundSubstreamRequest.

Injects an event coming from the outside in the handler.

Indicates to the handler that upgrading an outbound substream to the given protocol has failed.

Returns until when the connection should be kept alive.

This method is called by the Swarm after each invocation of ProtocolsHandler::poll to determine if the connection and the associated ProtocolsHandlers should be kept alive as far as this handler is concerned and if so, for how long.

Returning KeepAlive::No indicates that the connection should be closed and this handler destroyed immediately.

Returning KeepAlive::Until indicates that the connection may be closed and this handler destroyed after the specified Instant.

Returning KeepAlive::Yes indicates that the connection should be kept alive until the next call to this method.

Note: The connection is always closed and the handler destroyed when ProtocolsHandler::poll returns an error. Furthermore, the connection may be closed for reasons outside of the control of the handler.

Should behave like Stream::poll().

Provided methods

Notifies the handler of a change in the address of the remote.

Indicates to the handler that upgrading an inbound substream to the given protocol has failed.

Adds a closure that turns the input event into something else.

Adds a closure that turns the output event into something else.

Creates a new ProtocolsHandler that selects either this handler or other by delegating methods calls appropriately.

Note: The largest KeepAlive returned by the two handlers takes precedence, i.e. is returned from ProtocolsHandler::connection_keep_alive by the returned handler.

Creates a builder that allows creating a NodeHandler that handles this protocol exclusively.

Note: This method should not be redefined in a custom ProtocolsHandler.

Implementors