Don't always expect a PING on connect (#96)

In particular this fixes connecting to subway proxies, which reuse the
connection underneath, so usually don't send the ping.

libs/wasm-loader/src/lib.rs

@@ -16,9 +16,9 @@ use log::*;
 use serde::Deserialize;
 use std::fmt::Debug;
 use std::io::Read;
-use std::{fs::File, path::Path};
+use std::{fs::File, net::TcpStream, path::Path};
 use subrpcer::state;
-use tungstenite::Message;
+use tungstenite::{stream::MaybeTlsStream, Message, WebSocket};
 
 const CODE: &str = "0x3a636f6465"; // :code in hex
 pub const CODE_BLOB_BOMB_LIMIT: usize = 50 * 1024 * 1024;
@@ -36,24 +36,43 @@ pub struct WasmLoader {
 	compression: Compression,
 }
 
-impl WasmLoader {
-	/// Fetch the wasm blob from a node
-	fn fetch_wasm_from_rpc(reference: &OnchainBlock) -> Result<WasmBytes> {
-		#[derive(Deserialize)]
-		struct Response {
-			result: String,
-		}
+#[derive(Deserialize)]
+struct Response {
+	result: String,
+}
 
-		fn map_err<O, E1, E2>(r: std::result::Result<O, E1>, e: E2) -> std::result::Result<O, E2>
-		where
-			E1: Debug,
-		{
-			r.map_err(|e_| {
-				eprintln!("{e_:?}");
-				e
-			})
+fn map_err<O, E1, E2>(r: std::result::Result<O, E1>, e: E2) -> std::result::Result<O, E2>
+where
+	E1: Debug,
+{
+	r.map_err(|e_| {
+		eprintln!("{e_:?}");
+		e
+	})
+}
+
+impl WasmLoader {
+	fn read_wasm_hex_response_from_web_socket(
+		mut ws: WebSocket<MaybeTlsStream<TcpStream>>,
+		url: &String,
+	) -> Result<String> {
+		match map_err(ws.read(), WasmLoaderError::WsClient(url.to_string()))? {
+			Message::Text(t) => {
+				Ok(serde_json::from_str::<Response>(&t).map(|r| r.result).expect("unexpected response from node"))
+			}
+			Message::Ping(_) => {
+				log::debug!("Got ping from node, retrying.");
+				Self::read_wasm_hex_response_from_web_socket(ws, url)
+			}
+			m => {
+				log::warn!("Got unexpected message {:?} from node, retrying.", m);
+				Self::read_wasm_hex_response_from_web_socket(ws, url)
+			}
 		}
+	}
 
+	/// Fetch the wasm blob from a node
+	fn fetch_wasm_from_rpc(reference: &OnchainBlock) -> Result<WasmBytes> {
 		let block_ref = reference.block_ref.as_ref();
 		let data = state::get_storage(0, CODE, block_ref);
 		let wasm_hex = match &reference.endpoint {
@@ -70,19 +89,7 @@ impl WasmLoader {
 					ws.send(Message::Binary(serde_json::to_vec(&data).expect("invalid data"))),
 					WasmLoaderError::WsClient(url.to_string()),
 				)?;
-
-				let mut wasm_hex = None;
-
-				// One for Ping, one for response.
-				for _ in 0..2_u8 {
-					let Message::Text(t) = map_err(ws.read(), WasmLoaderError::WsClient(url.to_string()))? else {
-						continue;
-					};
-
-					wasm_hex = serde_json::from_str::<Response>(&t).map(|r| r.result).ok();
-				}
-
-				wasm_hex.expect("unexpected response from node")
+				Self::read_wasm_hex_response_from_web_socket(ws, url)?
 			}
 		};
 		let wasm = array_bytes::hex2bytes(wasm_hex).expect("Decoding bytes");