Working client

src/handshake.rs

@@ -1,8 +1,13 @@
+use sha1::{Digest, Sha1};
+use std::sync::Arc;
 use tokio::{
     io::{AsyncBufReadExt, AsyncWriteExt, BufReader},
     net::TcpStream,
+    sync::Mutex,
 };
 
+use crate::session::Session;
+
 pub async fn handle_websocket_handshake(stream: &mut TcpStream) -> std::io::Result<()> {
     let (read_half, mut write_half) = stream.split();
     let mut reader = BufReader::new(read_half);
@@ -75,3 +80,90 @@ pub async fn handle_websocket_handshake(stream: &mut TcpStream) -> std::io::Resu
     write_half.write_all(response.as_bytes()).await?;
     Ok(())
 }
+
+impl Session {
+    pub async fn new_client(mut stream: TcpStream) -> crate::Result<Self> {
+        crate::handshake::handle_websocket_handshake(&mut stream).await?;
+
+        let (read, write) = stream.into_split();
+
+        Ok(Self {
+            reader: Arc::new(Mutex::new(read)),
+            writer: Arc::new(Mutex::new(write)),
+            id: rand::random(),
+        })
+    }
+
+    /// Connect to a WebSocket server and perform the handshake
+    pub async fn new_server(addr: &str, path: &str) -> crate::Result<Self> {
+        // 1. TCP connect
+        let mut stream = TcpStream::connect(addr).await?;
+
+        // 2. Generate Sec-WebSocket-Key
+        let key_bytes: [u8; 16] = rand::random();
+        let key = base64::encode(&key_bytes);
+
+        // 3. Send HTTP Upgrade request
+        let request = format!(
+            "GET {} HTTP/1.1\r\n\
+             Host: {}\r\n\
+             Upgrade: websocket\r\n\
+             Connection: Upgrade\r\n\
+             Sec-WebSocket-Key: {}\r\n\
+             Sec-WebSocket-Version: 13\r\n\
+             \r\n",
+            path, addr, key
+        );
+        stream.write_all(request.as_bytes()).await?;
+        stream.flush().await?;
+
+        // 4. Read HTTP response
+        let mut reader = BufReader::new(&mut stream);
+        let mut status_line = String::new();
+        reader.read_line(&mut status_line).await?;
+        if !status_line.starts_with("HTTP/1.1 101") {
+            return Err(crate::Error::HandshakeFailed(format!(
+                "Expected 101 Switching Protocols, got: {}",
+                status_line.trim_end()
+            )));
+        }
+
+        // Read headers
+        let mut sec_accept = None;
+        loop {
+            let mut line = String::new();
+            reader.read_line(&mut line).await?;
+            let line = line.trim_end();
+            if line.is_empty() {
+                break; // end of headers
+            }
+            if let Some((k, v)) = line.split_once(':') {
+                if k.eq_ignore_ascii_case("sec-websocket-accept") {
+                    sec_accept = Some(v.trim().to_string());
+                }
+            }
+        }
+
+        // 5. Verify Sec-WebSocket-Accept
+        let expected = {
+            let mut sha1 = Sha1::new();
+            sha1.update(key.as_bytes());
+            sha1.update(b"258EAFA5-E914-47DA-95CA-C5AB0DC85B11");
+            base64::encode(sha1.finalize())
+        };
+        if sec_accept.as_deref() != Some(expected.as_str()) {
+            return Err(crate::Error::HandshakeFailed(
+                "Sec-WebSocket-Accept mismatch".into(),
+            ));
+        }
+
+        // 6. Upgrade succeeded, split stream
+        let (read, write) = stream.into_split();
+
+        Ok(Self {
+            reader: Arc::new(Mutex::new(read)),
+            writer: Arc::new(Mutex::new(write)),
+            id: rand::random(),
+        })
+    }
+}

src/lib.rs

@@ -14,6 +14,7 @@ pub enum Error {
     Io(std::io::Error),
     Json(serde_json::Error),
     InvalidFrame(String),
+    HandshakeFailed(String),
     ConnectionClosed,
 }
 

src/session.rs

@@ -9,23 +9,9 @@ use tokio::{
 };
 
 pub struct Session {
-    reader: Arc<Mutex<tokio::net::tcp::OwnedReadHalf>>,
-    writer: Arc<Mutex<tokio::net::tcp::OwnedWriteHalf>>,
-    id: u64,
-}
-
-impl Session {
-    pub async fn new(mut stream: TcpStream) -> crate::Result<Self> {
-        crate::handshake::handle_websocket_handshake(&mut stream).await?;
-
-        let (read, write) = stream.into_split();
-
-        Ok(Self {
-            reader: Arc::new(Mutex::new(read)),
-            writer: Arc::new(Mutex::new(write)),
-            id: rand::random(),
-        })
-    }
+    pub(crate) reader: Arc<Mutex<tokio::net::tcp::OwnedReadHalf>>,
+    pub(crate) writer: Arc<Mutex<tokio::net::tcp::OwnedWriteHalf>>,
+    pub(crate) id: u64,
 }
 
 impl Clone for Session {