Ethereum Provider Connect/Disconnect Events

Simple Summary

When an Ethereum Provider becomes connected or disconnected, it will emit a connect/disconnect event.

Abstract

The Provider is said to be “connected” when it can service RPC requests to at least one chain. The Provider is said to be “disconnected” when it cannot service RPC requests to any chain at all. When the Provider switches from a "connected" state to a "disconnected" state, it will emit a connect event. When the Provider switches from a "disconnected" state to a "connected" state, it will emit a disconnect event.

Motivation

When an application is hooked up to an Ethereum provider, there is value in having the application be alerted of connect/disconnect events that may occur so the application can appropriately inform the user of the situation. It is left up to the application to decide whether to listen in on these events, and how to handle them.

Specification

Definitions

Connected

The Provider is considered connected when it is able to service RPC requests to at least one chain.

Disconnected

The Provider is considered disconnected when it is unable to service RPC requests to any chain.

Events

connect

The Provider MUST emit a connect event to all attached EIP-2700 listeners if it transitions from a disconnected state to a connected state. All attached listeners MUST be called with the parameter { chainId }. chainId MUST specify the integer ID of the connected chain encoded as a hexadecimal string. If the Provider supports the eth_chainId JSON-RPC method or a derivation of it, then the chainId MUST match the return value of eth_chainId. The Provider MAY call the attached listeners in any order.

Rationale

This EIP is mostly a retrospective EIP meaning it codifies an already existing specification so there isn’t a lot of room for improving things such as by having a connect/disconnect event per chain.

Security Considerations

The relationship between Ethereum Provider and client is a trusted one, where it is assumed that the user implicitly trusts the Ethereum Provider which is how it managed to get injected into the client, or the client expressly pulled in a connection to it.

Copyright

Copyright and related rights waived via CC0.

Appendix I: Examples

// connect
provider.on('connect', ({ chainId }) => {
  console.log(`Provider connected to: ${chainId}`);
});