use crate::flow;
use crate::io::read_edges_binary;
use crate::types::{Address, Edge};
use json::JsonValue;
use std::collections::HashMap;
use std::error::Error;
use std::io::{BufRead, BufReader, Write};
use std::ops::Deref;
use std::sync::{Arc, 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) {
let edges: Arc>> = Arc::new(RwLock::new(Arc::new(HashMap::new())));
let listener =
TcpListener::bind(format!("127.0.0.1:{port}")).expect("Could not create server.");
loop {
let c = edges.clone();
match listener.accept() {
// TODO limit number of threads
Ok((socket, _)) => {
thread::spawn(move || {
match handle_connection(c.deref(), socket) {
Ok(()) => {}
Err(e) => {
// TODO respond to the jsonrpc
println!("Error handling connection: {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_result(request.id, len).as_bytes())?;
}
"compute_transfer" => {
println!("Computing flow");
let e = edges.read().unwrap().clone();
let (flow, transfers) = flow::compute_flow(
&Address::from(request.params["from"].to_string().as_str()),
&Address::from(request.params["to"].to_string().as_str()),
//&U256::from(request.params["value"].to_string().as_str()),
e.as_ref(),
);
println!("Computed flow");
// TODO error handling
socket.write_all(
jsonrpc_result(
request.id,
json::object! {
flow: flow.to_string(),
final: true,
transfers: transfers.into_iter().map(|e| json::object! {
from: e.from.to_string(),
to: e.to.to_string(),
token: e.token.to_string(),
value: e.capacity.to_string()
}).collect::>(),
},
)
.as_bytes(),
)?;
}
"cancel" => {}
"update_edges" => {}
// TODO error handling
_ => {}
};
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_result(id: JsonValue, result: impl Into) -> String {
let payload = json::object! {
jsonrpc: "2.0",
id: id,
result: result.into(),
}
.dump();
format!(
"HTTP/1.1 200 OK\r\nContent-Length: {}\r\n\r\n{}",
payload.len(),
payload
)
}