Module hooks 

Connection hooks for customizing connection establishment.

Connection hooks are attached when establishing connections and allow custom authentication, handshakes, or protocol negotiations. The ConnectionHook trait is called during connection setup, before the connection is used for messaging.

Built-in Hooks

The token module provides ready-to-use token-based authentication hooks:

• token::ServerHook - Server-side hook that validates client tokens
• token::ClientHook - Client-side hook that sends a token to the server

Custom Hooks

Implement ConnectionHook for custom authentication or protocol negotiation:

use msg_socket::hooks::{ConnectionHook, Error, HookResult};
use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};

struct MyAuth;

#[derive(Debug, thiserror::Error)]
enum MyAuthError {
    #[error("invalid token")]
    InvalidToken,
}

impl<Io> ConnectionHook<Io> for MyAuth
where
    Io: AsyncRead + AsyncWrite + Send + Unpin + 'static,
{
    type Error = MyAuthError;

    async fn on_connection(&self, mut io: Io) -> HookResult<Io, Self::Error> {
        let mut buf = [0u8; 32];
        io.read_exact(&mut buf).await?;
        if &buf == b"expected_token_value_32_bytes!!!" {
            io.write_all(b"OK").await?;
            Ok(io)
        } else {
            Err(Error::hook(MyAuthError::InvalidToken))
        }
    }
}

Future Extensions

TODO: Additional hooks may be added for different parts of the connection lifecycle (e.g., disconnection, reconnection, periodic health checks).

Modules

token

Token-based authentication connection hooks.

Enums

Error

Error type for connection hooks.

Traits

ConnectionHook

Connection hook executed during connection establishment.

Type Aliases

HookResult

Result type for connection hooks.