Update README

Signed-off-by: trivernis <trivernis@protonmail.com>

Cargo.toml

@@ -20,3 +20,4 @@ sha2 = "0.9.2"
 generic-array = "0.14.4"
 typenum = "1.12.0"
 x25519-dalek = "1.1.0"
+crossbeam-utils = "0.8.0"

README.md

@@ -1,3 +1,45 @@
 # Vented
 
-Vented is an event based TCP server that uses message pack for payload data.
+Vented is an event based TCP server with encryption that uses message pack for payload data.
+
+## Encryption
+
+Vented uses key cryptography to encrypt the connection between the client and the serve.
+The authenticity of both parties is validated by global public keys that need to be known
+to both parties beforehand. The encryption itself uses randomly generated keys and a nonce
+that corresponds to the message number. The crate used for encryption is [crypto_box](https://crates.io/crates/crypto_box)
+which the [XChaCha20Poly1305](https://github.com/RustCrypto/AEADs/tree/master/chacha20poly1305) encryption.
+The crate used for the key exchanges is [x25519-dalek](https://crates.io/crates/x25519-dalek).
+
+## Usage
+
+ ```rust
+use vented::server::VentedServer;
+use vented::server::data::Node;
+use vented::crypto::SecretKey;
+use rand::thread_rng;
+use vented::event::Event;
+
+fn main() {
+    let nodes = vec![
+        Node {
+            id: "B".to_string(),
+            address: None,
+            public_key: global_secret_b.public_key() // load it from somewhere
+        },
+    ];
+    // in a real world example the secret key needs to be loaded from somewhere because connections
+    // with unknown keys are not accepted.
+    let global_secret = SecretKey::new(&mut thread_rng());
+    let mut server = VentedServer::new("A".to_string(), global_secret, nodes.clone(), 4);
+    
+    
+    server.listen("localhost:20000".to_string());
+    server.on("pong", |_event| {
+        println!("Pong!");
+        
+        None    // the return value is the response event Option<Event>
+    });
+    server.emit("B".to_string(), Event::new("ping".to_string())).unwrap();
+}
+ ```

src/crypto/mod.rs

@@ -13,6 +13,8 @@ use typenum::U24;
 use crate::event::Event;
 use crate::result::VentedResult;
 
+pub use crypto_box::SecretKey;
+
 /// A cryptographical stream object that handles encryption and decryption of streams
 #[derive(Clone)]
 pub struct CryptoStream {

src/event_handler/mod.rs

@@ -20,8 +20,8 @@ impl EventHandler {
 
     /// Adds a handler for the given event
     pub fn on<F: 'static>(&mut self, event_name: &str, handler: F)
-        where
-            F: Fn(Event) -> Option<Event> + Send + Sync,
+    where
+        F: Fn(Event) -> Option<Event> + Send + Sync,
     {
         match self.event_handlers.get_mut(event_name) {
             Some(handlers) => handlers.push(Box::new(handler)),

src/server/mod.rs

@@ -14,6 +14,7 @@ use crate::server::server_events::{
     AuthPayload, NodeInformationPayload, AUTH_EVENT, CONNECT_EVENT, CONN_ACCEPT_EVENT,
     CONN_CHALLENGE_EVENT, CONN_REJECT_EVENT, READY_EVENT,
 };
+use crossbeam_utils::sync::WaitGroup;
 use parking_lot::Mutex;
 use std::io::Write;
 use std::sync::Arc;
@@ -24,6 +25,35 @@ pub mod data;
 pub mod server_events;
 
 /// The vented server that provides parallel handling of connections
+/// Usage:
+/// ```rust
+/// use vented::server::VentedServer;
+/// use vented::server::data::Node;
+/// use vented::crypto::SecretKey;
+/// use rand::thread_rng;
+/// use vented::event::Event;
+///
+/// let nodes = vec![
+/// Node {
+///        id: "B".to_string(),
+///        address: None,
+///        public_key: global_secret_b.public_key() // load it from somewhere
+///    },
+///];
+/// // in a real world example the secret key needs to be loaded from somewhere because connections
+/// // with unknown keys are not accepted.
+/// let global_secret = SecretKey::new(&mut thread_rng());
+/// let mut server = VentedServer::new("A".to_string(), global_secret, nodes.clone(), 4);
+///
+///
+/// server.listen("localhost:20000".to_string());
+/// server.on("pong", |_event| {
+///    println!("Pong!");
+///    
+///    None    // the return value is the response event Option<Event>
+/// });
+/// server.emit("B".to_string(), Event::new("ping".to_string())).unwrap();
+/// ```
 pub struct VentedServer {
     connections: Arc<Mutex<HashMap<String, CryptoStream>>>,
     known_nodes: Arc<Mutex<Vec<Node>>>,
@@ -35,6 +65,10 @@ pub struct VentedServer {
 }
 
 impl VentedServer {
+    /// Creates a new vented server with a given node_id and secret key that are
+    /// used to authenticate against other servers.
+    /// The given nodes are used for authentication.
+    /// The server runs with 2x the given amount of threads.
     pub fn new(
         node_id: String,
         secret_key: SecretKey,
@@ -53,14 +87,19 @@ impl VentedServer {
     }
 
     /// Emits an event to the specified Node
-    pub fn emit(&self, node_id: String, event: Event) -> VentedResult<()> {
+    /// The actual writing is done in a separate thread from the thread pool.
+    /// With the returned waitgroup one can wait for the event to be written.
+    pub fn emit(&self, node_id: String, event: Event) -> VentedResult<WaitGroup> {
         let handler = self.connections.lock().get(&node_id).cloned();
+        let wg = WaitGroup::new();
+        let wg2 = WaitGroup::clone(&wg);
 
         if let Some(handler) = handler {
             self.sender_pool.lock().execute(move || {
                 handler.send(event).expect("Failed to send event");
+                std::mem::drop(wg);
             });
-            Ok(())
+            Ok(wg2)
         } else {
             let found_node = self
                 .known_nodes
@@ -73,8 +112,9 @@ impl VentedServer {
                     let handler = self.connect(address.clone())?;
                     self.sender_pool.lock().execute(move || {
                         handler.send(event).expect("Failed to send event");
+                        std::mem::drop(wg);
                     });
-                    Ok(())
+                    Ok(wg2)
                 } else {
                     Err(VentedError::NotAServer(node_id))
                 }
@@ -84,7 +124,10 @@ impl VentedServer {
         }
     }
 
-    /// Adds a handler for the given event
+    /// Adds a handler for the given event.
+    /// The event returned by the handler is returned to the server.
+    /// If there is more than one handler, the response will be piped to the next handler.
+    /// The oder is by order of insertion. The first registered handler will be executed first.
     pub fn on<F: 'static>(&mut self, event_name: &str, handler: F)
     where
         F: Fn(Event) -> Option<Event> + Send + Sync,
@@ -93,11 +136,18 @@ impl VentedServer {
     }
 
     /// Starts listening on the specified address (with port!)
-    pub fn listen(&mut self, address: String) {
+    /// This will cause a new thread to start up so that the method returns immediately
+    /// With the returned wait group one can wait for the server to be ready.
+    /// The method can be called multiple times to start listeners on multiple ports.
+    pub fn listen(&mut self, address: String) -> WaitGroup {
         let context = self.get_server_context();
+        let wg = WaitGroup::new();
+        let wg2 = WaitGroup::clone(&wg);
 
-        thread::spawn(move || match TcpListener::bind(address) {
+        thread::spawn(move || match TcpListener::bind(&address) {
             Ok(listener) => {
+                log::info!("Listener running on {}", address);
+                std::mem::drop(wg);
                 for connection in listener.incoming() {
                     match connection {
                         Ok(stream) => {
@@ -109,8 +159,13 @@ impl VentedServer {
                     }
                 }
             }
-            Err(e) => log::error!("Failed to bind listener: {}", e),
+            Err(e) => {
+                log::error!("Failed to bind listener: {}", e);
+                std::mem::drop(wg);
+            }
         });
+
+        wg2
     }
 
     /// Returns a copy of the servers metadata

tests/test_communication.rs

@@ -30,8 +30,8 @@ fn test_server_communication() {
     ];
     let mut server_a = VentedServer::new("A".to_string(), global_secret_a, nodes.clone(), 4);
     let mut server_b = VentedServer::new("B".to_string(), global_secret_b, nodes, 4);
-    server_a.listen("localhost:22222".to_string());
-    thread::sleep(Duration::from_millis(10));
+    let wg = server_a.listen("localhost:22222".to_string());
+    wg.wait();
 
     server_a.on("ping", {
         let ping_count = Arc::clone(&ping_count);
@@ -63,14 +63,15 @@ fn test_server_communication() {
         }
     });
     for _ in 0..10 {
-        server_b
+        let wg = server_b
             .emit("A".to_string(), Event::new("ping".to_string()))
             .unwrap();
-        thread::sleep(Duration::from_millis(10));
+        wg.wait();
     }
-    server_a
+    let wg = server_a
         .emit("B".to_string(), Event::new("pong".to_string()))
         .unwrap();
+    wg.wait();
 
     // wait one second to make sure the servers were able to process the events
     for _ in 0..100 {