Module libp2prs_core::upgrade[−][src]

Contains everything related to upgrading a connection to use a protocol.

After a connection with a remote has been successfully established. The next step is to upgrade this connection to use a protocol.

This is where the Upgrader traits come into play. The trait is implemented on types that represent a collection of one or more possible protocols for respectively an ingoing or outgoing connection.

Note: Multiple versions of the same protocol are treated as different protocols. For example, /foo/1.0.0 and /foo/1.1.0 are totally unrelated as far as upgrading is concerned.

Upgrade process

An upgrade is performed in two steps:

  • A protocol negotiation step. The UpgradeInfo::protocol_info method is called to determine which protocols are supported by the trait implementation. The multistream-select protocol is used in order to agree on which protocol to use amongst the ones supported.

  • A handshake. After a successful negotiation, the Upgrader::upgrade_inbound or Upgrader::upgrade_outbound method is called. This method will return a upgraded ‘Connection’. This handshake is considered mandatory, however in practice it is possible for the trait implementation to return a dummy Connection that doesn’t perform any action and immediately succeeds.

After an upgrade is successful, an object of type Upgrader::Output is returned. The actual object depends on the implementation and there is no constraint on the traits that it should implement, however it is expected that it can be used by the user to control the behaviour of the protocol.

Structs

DummyUpgrader

Implementation of dummy Upgrader that doesn’t do anything practice.

ProtocolId

A general new type implementation of ProtocolName trait.

Selector

Select two upgrades into one. Supports all the protocols supported by either sub-upgrade.

Traits

ProtocolName

Types serving as protocol names.

UpgradeInfo
Upgrader

Common trait for upgrades that can be applied on a connection.