use crate::Result; use anyhow::Context; use jsonrpc_core as jsonrpc; use log::{error, info}; use serde::{Deserialize, Serialize}; use serde_json::Value; use std::collections::HashMap; use std::sync::Arc; use tokio::{ io::{AsyncBufRead, AsyncBufReadExt, AsyncReadExt, AsyncWriteExt, BufReader, BufWriter}, process::{ChildStderr, ChildStdin, ChildStdout}, sync::{ mpsc::{unbounded_channel, Sender, UnboundedReceiver, UnboundedSender}, Mutex, }, }; #[derive(Debug)] pub enum Payload { Request { chan: Sender>, value: jsonrpc::MethodCall, }, Notification(jsonrpc::Notification), Response(jsonrpc::Output), } /// A type representing all possible values sent from the server to the client. #[derive(Debug, PartialEq, Clone, Deserialize, Serialize)] #[serde(deny_unknown_fields)] #[serde(untagged)] enum ServerMessage { /// A regular JSON-RPC request output (single response). Output(jsonrpc::Output), /// A JSON-RPC request or notification. Call(jsonrpc::Call), } #[derive(Debug)] pub struct Transport { id: usize, pending_requests: Mutex>>>, } impl Transport { pub fn start( server_stdout: BufReader, server_stdin: BufWriter, server_stderr: BufReader, id: usize, ) -> ( UnboundedReceiver<(usize, jsonrpc::Call)>, UnboundedSender, ) { let (client_tx, rx) = unbounded_channel(); let (tx, client_rx) = unbounded_channel(); let transport = Self { id, pending_requests: Mutex::new(HashMap::default()), }; let transport = Arc::new(transport); tokio::spawn(Self::recv(transport.clone(), server_stdout, client_tx)); tokio::spawn(Self::err(transport.clone(), server_stderr)); tokio::spawn(Self::send(transport, server_stdin, client_rx)); (rx, tx) } async fn recv_server_message( reader: &mut (impl AsyncBufRead + Unpin + Send), buffer: &mut String, ) -> Result { let mut content_length = None; loop { buffer.truncate(0); reader.read_line(buffer).await?; let header = buffer.trim(); if header.is_empty() { break; } let mut parts = header.split(": "); match (parts.next(), parts.next(), parts.next()) { (Some("Content-Length"), Some(value), None) => { content_length = Some(value.parse().context("invalid content length")?); } (Some(_), Some(_), None) => {} _ => { return Err(std::io::Error::new( std::io::ErrorKind::Other, "Failed to parse header", ) .into()); } } } let content_length = content_length.context("missing content length")?; //TODO: reuse vector let mut content = vec![0; content_length]; reader.read_exact(&mut content).await?; let msg = std::str::from_utf8(&content).context("invalid utf8 from server")?; info!("<- {}", msg); // try parsing as output (server response) or call (server request) let output: serde_json::Result = serde_json::from_str(msg); Ok(output?) } async fn recv_server_error( err: &mut (impl AsyncBufRead + Unpin + Send), buffer: &mut String, ) -> Result<()> { buffer.truncate(0); err.read_line(buffer).await?; error!("err <- {}", buffer); Ok(()) } async fn send_payload_to_server( &self, server_stdin: &mut BufWriter, payload: Payload, ) -> Result<()> { //TODO: reuse string let json = match payload { Payload::Request { chan, value } => { self.pending_requests .lock() .await .insert(value.id.clone(), chan); serde_json::to_string(&value)? } Payload::Notification(value) => serde_json::to_string(&value)?, Payload::Response(error) => serde_json::to_string(&error)?, }; self.send_string_to_server(server_stdin, json).await } async fn send_string_to_server( &self, server_stdin: &mut BufWriter, request: String, ) -> Result<()> { info!("-> {}", request); // send the headers server_stdin .write_all(format!("Content-Length: {}\r\n\r\n", request.len()).as_bytes()) .await?; // send the body server_stdin.write_all(request.as_bytes()).await?; server_stdin.flush().await?; Ok(()) } async fn process_server_message( &self, client_tx: &UnboundedSender<(usize, jsonrpc::Call)>, msg: ServerMessage, ) -> Result<()> { match msg { ServerMessage::Output(output) => self.process_request_response(output).await?, ServerMessage::Call(call) => { client_tx .send((self.id, call)) .context("failed to send a message to server")?; // let notification = Notification::parse(&method, params); } }; Ok(()) } async fn process_request_response(&self, output: jsonrpc::Output) -> Result<()> { let (id, result) = match output { jsonrpc::Output::Success(jsonrpc::Success { id, result, .. }) => { info!("<- {}", result); (id, Ok(result)) } jsonrpc::Output::Failure(jsonrpc::Failure { id, error, .. }) => { error!("<- {}", error); (id, Err(error.into())) } }; let tx = self .pending_requests .lock() .await .remove(&id) .expect("pending_request with id not found!"); match tx.send(result).await { Ok(_) => (), Err(_) => error!( "Tried sending response into a closed channel (id={:?}), original request likely timed out", id ), }; Ok(()) } async fn recv( transport: Arc, mut server_stdout: BufReader, client_tx: UnboundedSender<(usize, jsonrpc::Call)>, ) { let mut recv_buffer = String::new(); loop { match Self::recv_server_message(&mut server_stdout, &mut recv_buffer).await { Ok(msg) => { match transport.process_server_message(&client_tx, msg).await { Ok(_) => {} Err(err) => { error!("err: <- {:?}", err); break; } }; } Err(err) => { error!("err: <- {:?}", err); break; } } } } async fn err(_transport: Arc, mut server_stderr: BufReader) { let mut recv_buffer = String::new(); loop { match Self::recv_server_error(&mut server_stderr, &mut recv_buffer).await { Ok(_) => {} Err(err) => { error!("err: <- {:?}", err); break; } } } } async fn send( transport: Arc, mut server_stdin: BufWriter, mut client_rx: UnboundedReceiver, ) { while let Some(msg) = client_rx.recv().await { match transport .send_payload_to_server(&mut server_stdin, msg) .await { Ok(_) => {} Err(err) => { error!("err: <- {:?}", err); } } } } }