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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 tokio::{
io::{AsyncBufRead, AsyncBufReadExt, AsyncReadExt, AsyncWriteExt, BufReader, BufWriter},
process::{ChildStderr, ChildStdin, ChildStdout},
sync::mpsc::{unbounded_channel, Sender, UnboundedReceiver, UnboundedSender},
};
#[derive(Debug)]
pub enum Payload {
Request {
chan: Sender<Result<Value>>,
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,
client_tx: UnboundedSender<(usize, jsonrpc::Call)>,
client_rx: UnboundedReceiver<Payload>,
pending_requests: HashMap<jsonrpc::Id, Sender<Result<Value>>>,
server_stdin: BufWriter<ChildStdin>,
server_stdout: BufReader<ChildStdout>,
server_stderr: BufReader<ChildStderr>,
}
impl Transport {
pub fn start(
server_stdout: BufReader<ChildStdout>,
server_stdin: BufWriter<ChildStdin>,
server_stderr: BufReader<ChildStderr>,
id: usize,
) -> (
UnboundedReceiver<(usize, jsonrpc::Call)>,
UnboundedSender<Payload>,
) {
let (client_tx, rx) = unbounded_channel();
let (tx, client_rx) = unbounded_channel();
let transport = Self {
id,
server_stdout,
server_stdin,
server_stderr,
client_tx,
client_rx,
pending_requests: HashMap::default(),
};
tokio::spawn(transport.duplex());
(rx, tx)
}
async fn recv_server_message(
reader: &mut (impl AsyncBufRead + Unpin + Send),
buffer: &mut String,
) -> Result<ServerMessage> {
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 = String::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<ServerMessage> = 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(&mut self, payload: Payload) -> Result<()> {
//TODO: reuse string
let json = match payload {
Payload::Request { chan, value } => {
self.pending_requests.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(json).await
}
async fn send_string_to_server(&mut self, request: String) -> Result<()> {
info!("-> {}", request);
// send the headers
self.server_stdin
.write_all(format!("Content-Length: {}\r\n\r\n", request.len()).as_bytes())
.await?;
// send the body
self.server_stdin.write_all(request.as_bytes()).await?;
self.server_stdin.flush().await?;
Ok(())
}
async fn process_server_message(&mut self, msg: ServerMessage) -> Result<()> {
match msg {
ServerMessage::Output(output) => self.process_request_response(output).await?,
ServerMessage::Call(call) => {
self.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(&mut 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
.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 duplex(mut self) {
let mut recv_buffer = String::new();
let mut err_buffer = String::new();
loop {
tokio::select! {
// client -> server
msg = self.client_rx.recv() => {
match msg {
Some(msg) => {
self.send_payload_to_server(msg).await.unwrap()
},
None => break
}
}
// server -> client
msg = Self::recv_server_message(&mut self.server_stdout, &mut recv_buffer) => {
match msg {
Ok(msg) => {
self.process_server_message(msg).await.unwrap();
}
Err(_) => {
error!("err: <- {:?}", msg);
break;
},
}
}
_msg = Self::recv_server_error(&mut self.server_stderr, &mut err_buffer) => {}
}
}
}
}
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