1 //! This Rust crate provides a simple, brokerless message-queue abstraction over asynchronous
2 //! network streams. It guarantees ordered message delivery and reception, and both TCP and TLS
3 //! transports are supported.
8 //! // create a client connection to the server
9 //! let mut conn = Connection::tcp_client(ip_address).await?;
11 //! // construct a new message
12 //! let msg = String::from("Hello world!");
13 //! let envelope: ConnectDatagram = ConnectDatagram::new(65535, msg.into_bytes())?;
15 //! // send a message to the server
16 //! conn.writer().send(envelope).await?;
18 //! // wait for the echo-server to reply with an echo
19 //! if let Some(mut envelope) = conn.reader().next().await {
20 //! // take the message payload from the envelope
21 //! let data: Vec<u8> = envelope.take_data().unwrap();
23 //! // reconstruct the original message
24 //! let msg = String::from_utf8(data)?;
25 //! assert_eq!("Hello world!", msg.as_str());
29 //! In addition to the [crate documentation](https://docs.rs/connect/latest/connect/), please use
30 //! the provided [example programs](https://github.com/sachanganesh/connect-rs/tree/main/examples)
31 //! as a practical reference for crate usage.
34 //! - [TCP Echo Server](https://github.com/sachanganesh/connect-rs/tree/main/examples/tcp-echo-server)
35 //! - [TCP Client](https://github.com/sachanganesh/connect-rs/tree/main/examples/tcp-client)
36 //! - TLS (enable `tls` feature flag)
37 //! - [TLS Echo Server](https://github.com/sachanganesh/connect-rs/tree/main/examples/tls-echo-server)
38 //! - [TLS Client](https://github.com/sachanganesh/connect-rs/tree/main/examples/tls-client)
42 //! When building networked applications, developers shouldn't have to focus on repeatedly solving
43 //! the problem of reliable, ordered message delivery over byte-streams. By using a message
44 //! queue abstraction, crate users can focus on core application logic and leave the low-level
45 //! networking and message-queue guarantees to the abstraction.
47 //! Connect provides a `ConnectionWriter` and `ConnectionReader` interface to concurrently send
48 //! and receive messages over a network connection. Each user-provided message is prefixed by 8
49 //! bytes, containing a size-prefix (4 bytes), version tag (2 bytes), and recipient tag (2 bytes).
50 //! The size-prefix and version tag are used internally to deserialize messages received from the
51 //! network connection. The recipient tag is intended for crate users to identify the message
52 //! recipient, although the library leaves that up to the user's discretion.
54 //! Library users must serialize their custom messages into bytes (`Vec<u8>`), prior to
55 //! constructing a `ConnectDatagram`, which can then be passed to a `ConnectionWriter`.
56 //! Consequently, `ConnectionReader`s will return `ConnectDatagram`s containing the message payload
57 //! (`Vec<u8>` again) to the user to deserialize.
59 //! Requiring crate users to serialize data before constructing a datagram may appear redundant, but
60 //! gives the developer the freedom to use a serialization format of their choosing. This means that
61 //! library users can do interesting things such as:
63 //! - Use the recipient tag to signify which serialization format was used for that message
64 //! - Use the recipient tag to signify the type of message being sent
68 //! - `tls`: enables usage of tls transport functionality
71 // #![feature(doc_cfg)]
79 #[cfg(feature = "tls")]
80 // #[doc(cfg(feature = "tls"))]
83 use async_std::{net::SocketAddr, pin::Pin};
84 use futures::{AsyncRead, AsyncWrite, Sink, Stream};
86 pub use crate::protocol::{
87 ConnectDatagram, DatagramError, DATAGRAM_HEADER_BYTE_SIZE, SIZE_PREFIX_BYTE_SIZE,
89 pub use crate::reader::ConnectionReader;
90 pub use crate::writer::{ConnectionWriteError, ConnectionWriter};
91 pub use futures::{SinkExt, StreamExt};
93 /// Wrapper around a [`ConnectionReader`] and [`ConnectionWriter`] to read and write on a network
95 pub struct Connection {
96 local_addr: SocketAddr,
97 peer_addr: SocketAddr,
98 reader: Box<dyn Stream<Item = ConnectDatagram> + Unpin + Send + Sync>,
99 writer: Box<dyn Sink<ConnectDatagram, Error = ConnectionWriteError> + Unpin + Send + Sync>,
105 local_addr: SocketAddr,
106 peer_addr: SocketAddr,
107 read_stream: Pin<Box<dyn AsyncRead + Send + Sync>>,
108 write_stream: Pin<Box<dyn AsyncWrite + Send + Sync>>,
113 reader: Box::new(ConnectionReader::new(local_addr, peer_addr, read_stream)),
114 writer: Box::new(ConnectionWriter::new(local_addr, peer_addr, write_stream)),
118 /// Get the local IP address and port.
119 pub fn local_addr(&self) -> SocketAddr {
120 self.local_addr.clone()
123 /// Get the peer IP address and port.
124 pub fn peer_addr(&self) -> SocketAddr {
125 self.peer_addr.clone()
128 /// Consume the [`Connection`] to split into separate [`ConnectionReader`] and
129 /// [`ConnectionWriter`] halves.
131 /// [`Connection`]s are split when reading and writing must be concurrent operations.
135 impl Stream<Item = ConnectDatagram> + Send + Sync,
136 impl Sink<ConnectDatagram, Error = ConnectionWriteError> + Send + Sync,
138 (self.reader, self.writer)
141 /// Re-wrap the [`ConnectionReader`] and [`ConnectionWriter`] halves into a [`Connection`].
143 local_addr: SocketAddr,
144 peer_addr: SocketAddr,
145 reader: impl Stream<Item = ConnectDatagram> + Unpin + Send + Sync + 'static,
146 writer: impl Sink<ConnectDatagram, Error = ConnectionWriteError> + Unpin + Send + Sync + 'static,
151 reader: Box::new(reader),
152 writer: Box::new(writer),
156 /// Get mutable access to the underlying [`ConnectionReader`].
157 pub fn reader(&mut self) -> &mut impl Stream<Item = ConnectDatagram> {
161 /// Get mutable access to the underlying [`ConnectionWriter`].
162 pub fn writer(&mut self) -> &mut impl Sink<ConnectDatagram, Error = ConnectionWriteError> {
166 /// Close the connection by closing both the reading and writing halves.
167 pub async fn close(self) -> SocketAddr {
168 let peer_addr = self.peer_addr();
169 let (reader, writer) = self.split();
173 // writer.close().await;