79 lines
2.7 KiB
Rust
79 lines
2.7 KiB
Rust
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//! Code for creating isolated connections to specific peers.
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use std::{
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future::Future,
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pin::Pin,
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task::{Context, Poll},
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};
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use futures::future::{FutureExt, TryFutureExt};
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use tokio::net::TcpStream;
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use tower::{
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util::{BoxService, Oneshot},
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Service,
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};
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use crate::{peer, BoxedStdError, Config, Request, Response};
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/// Use the provided TCP connection to create a Zcash connection completely
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/// isolated from all other node state.
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///
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/// The connection pool returned by `init` should be used for all requests that
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/// don't require isolated state or use of an existing TCP connection. However,
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/// this low-level API is useful for custom network crawlers or Tor connections.
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///
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/// In addition to being completely isolated from all other node state, this
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/// method also aims to be minimally distinguishable from other clients.
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///
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/// Note that this method does not implement any timeout behavior, so callers may
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/// want to layer it with a timeout as appropriate for their application.
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///
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/// # Inputs
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///
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/// - `conn`: an existing TCP connection to use. Passing an existing TCP
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/// connection allows this method to be used with clearnet or Tor transports.
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///
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/// - `user_agent`: a valid BIP14 user-agent, e.g., the empty string.
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pub async fn connect_isolated(
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conn: TcpStream,
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user_agent: String,
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) -> Result<BoxService<Request, Response, BoxedStdError>, BoxedStdError> {
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let handshake = peer::Handshake::builder()
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.with_config(Config::default())
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.with_inbound_service(tower::service_fn(|_req| async move {
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Ok::<Response, BoxedStdError>(Response::Nil)
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}))
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.with_user_agent(user_agent)
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.finish()
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.expect("provided mandatory builder parameters");
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// We can't get the remote addr from conn, because it might be a tcp
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// connection through a socks proxy, not directly to the remote. But it
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// doesn't seem like zcashd cares if we give a bogus one, and Zebra doesn't
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// touch it at all.
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let remote_addr = "0.0.0.0:8233".parse().unwrap();
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let client = Oneshot::new(handshake, (conn, remote_addr)).await?;
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Ok(BoxService::new(Wrapper(client)))
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}
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// This can be deleted when a new version of Tower with map_err is released.
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struct Wrapper(peer::Client);
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impl Service<Request> for Wrapper {
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type Response = Response;
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type Error = BoxedStdError;
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type Future =
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Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send + 'static>>;
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fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
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self.0.poll_ready(cx).map_err(Into::into)
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}
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fn call(&mut self, req: Request) -> Self::Future {
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self.0.call(req).map_err(Into::into).boxed()
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}
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}
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