use crate::graph; use crate::io::read_edges_binary; use crate::types::{Address, Edge, U256}; use json::JsonValue; use std::collections::HashMap; use std::error::Error; use std::io::{BufRead, BufReader, Write}; use std::ops::Deref; use std::sync::{mpsc, Arc, Mutex, RwLock}; use std::thread; use std::{ io::Read, net::{TcpListener, TcpStream}, }; struct JsonRpcRequest { id: JsonValue, method: String, params: JsonValue, } type EdgeMap = HashMap>; pub fn start_server(port: u16, queue_size: usize, threads: u64) { let edges: Arc>> = Arc::new(RwLock::new(Arc::new(HashMap::new()))); let (sender, receiver) = mpsc::sync_channel(queue_size); let protected_receiver = Arc::new(Mutex::new(receiver)); for _ in 0..threads { let rec = protected_receiver.clone(); let e = edges.clone(); thread::spawn(move || { loop { let socket = rec.lock().unwrap().recv().unwrap(); match handle_connection(e.deref(), socket) { Ok(()) => {} Err(e) => { // TODO respond to the jsonrpc println!("Error handling connection: {e}"); } } } }); } let listener = TcpListener::bind(format!("127.0.0.1:{port}")).expect("Could not create server."); loop { match listener.accept() { Ok((socket, _)) => match sender.try_send(socket) { Ok(()) => {} Err(e) => println!("Queue full: {e}"), }, Err(e) => println!("Error accepting connection: {e}"), } } } fn handle_connection( edges: &RwLock>>>, mut socket: TcpStream, ) -> Result<(), Box> { let request = read_request(&mut socket)?; match request.method.as_str() { "load_edges_binary" => { let updated_edges = read_edges_binary(&request.params["file"].to_string())?; let len = updated_edges.len(); *edges.write().unwrap() = Arc::new(updated_edges); socket.write_all(jsonrpc_response(request.id, len).as_bytes())?; } "compute_transfer" => { println!("Computing flow"); let e = edges.read().unwrap().clone(); compute_transfer(request, e.as_ref(), socket)?; } "cancel" => {} "update_edges" => {} // TODO error handling _ => {} }; Ok(()) } fn compute_transfer( request: JsonRpcRequest, edges: &HashMap>, mut socket: TcpStream, ) -> Result<(), Box> { socket.write_all(chunked_header().as_bytes())?; let max_distances = if request.params["iterative"].as_bool().unwrap_or_default() { vec![Some(1), Some(2), None] } else { vec![None] }; for max_distance in max_distances { let (flow, transfers) = graph::compute_flow( &Address::from(request.params["from"].to_string().as_str()), &Address::from(request.params["to"].to_string().as_str()), edges, if request.params.has_key("value") { U256::from(request.params["value"].to_string().as_str()) } else { U256::MAX }, max_distance, ); println!( "Computed flow with max distance {:?}: {}", max_distance, flow ); // TODO error handling socket.write_all( chunked_response( &(jsonrpc_result( request.id.clone(), json::object! { flow: flow.to_string(), final: max_distance.is_none(), transfers: transfers.into_iter().map(|e| json::object! { from: e.from.to_string(), to: e.to.to_string(), token_owner: e.token.to_string(), value: e.capacity.to_string() }).collect::>(), }, ) + "\r\n"), ) .as_bytes(), )?; } socket.write_all(chunked_close().as_bytes())?; Ok(()) } fn read_request(socket: &mut TcpStream) -> Result> { let payload = read_payload(socket)?; let mut request = json::parse(&String::from_utf8(payload)?)?; println!("Request: {request}"); let id = request["id"].take(); let params = request["params"].take(); match request["method"].as_str() { Some(method) => Ok(JsonRpcRequest { id, method: method.to_string(), params, }), _ => Err(From::from("Invalid JSON-RPC request: {request}")), } } fn read_payload(socket: &mut TcpStream) -> Result, Box> { let mut reader = BufReader::new(socket); let mut length = 0; for result in reader.by_ref().lines() { let l = result?; if l.is_empty() { break; } let header = "content-length: "; if l.to_lowercase().starts_with(header) { length = l[header.len()..].parse::()?; } } let mut payload = vec![0u8; length]; reader.read_exact(payload.as_mut_slice())?; Ok(payload) } fn jsonrpc_response(id: JsonValue, result: impl Into) -> String { let payload = jsonrpc_result(id, result); format!( "HTTP/1.1 200 OK\r\nContent-Length: {}\r\n\r\n{}", payload.len(), payload ) } fn jsonrpc_result(id: JsonValue, result: impl Into) -> String { json::object! { jsonrpc: "2.0", id: id, result: result.into(), } .dump() } fn chunked_header() -> String { "HTTP/1.1 200 OK\r\nTransfer-Encoding: chunked\r\n\r\n".to_string() } fn chunked_response(data: &str) -> String { if data.is_empty() { String::new() } else { format!("{:x}\r\n{}\r\n", data.len(), data) } } fn chunked_close() -> String { "0\r\n\r\n".to_string() }