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//! This library provides a toolkit for rapid protocol development and usage, //! working with the rest of the Tokio stack. //! //! You can find extensive documentation and tutorials in addition to this //! documentation at [https://tokio.rs](https://tokio.rs) //! //! # Protocols //! //! Here, a **protocol** is a way of providing or consuming a service. Protocols //! are implemented via traits, which are arranged into a taxonomy: //! //! - `pipeline::{ClientProto, ServerProto}` //! - `multiplex::{ClientProto, ServerProto}` //! - `streaming::pipeline::{ClientProto, ServerProto}` //! - `streaming::multiplex::{ClientProto, ServerProto}` //! //! ### Pipeline vs multiplex //! //! By default, protocols allow a client to transmit multiple requests without //! waiting for the corresponding responses, which is commonly used to improve //! the throughput of single connections. //! //! In a **pipelined protocol**, the server responds to client requests in the //! order they were sent. Example pipelined protocols include HTTP/1.1 and Redis. //! Pipelining with the max number of in-flight requests set to 1 implies that //! for each request, the response must be received before sending another //! request on the same connection. //! //! In a **multiplexed protocol**, the server responds to client requests in the //! order of completion. Request IDs are used to match responses back to requests. //! //! In both cases, if multiple requests are sent, the service running on the //! server *may* process them concurrently, although many services will impose //! some restrictions depending on the request type. //! //! ### Streaming //! //! In a non-streaming protocols, the client sends a complete request in a //! single message, and the server provides a complete response in a single //! message. Protocol tools in this style are available in the top-level `pipeline` //! and `multiplex` modules. //! //! In a **streaming protocol**, requests and responses can carry **body //! streams**, which allows partial processing before the complete body has been //! transferred. Streaming protocol tools are found within the `streaming` //! submodule. //! //! # Transports //! //! A key part of any protocol is its **transport**, which is the way that it //! sends and receives *frames* on its connection. For simple protocols, these //! frames correspond directly to complete requests and responses. For more //! complicated protocols, they carry additional metadata, and may only be one //! part of a request or response body. //! //! Transports are defined by implementing the `transport::Transport` trait. The //! `transport::CodecTransport` type can be used to wrap a `Codec` (from //! `tokio-core`), which is a simple way to build a transport. //! //! # An example server //! //! The following code shows how to implement a simple server that receives //! newline-separated integer values, doubles them, and returns them. It //! illustrates several aspects of the Tokio stack: //! //! - Implementing a codec `IntCodec` for reading and writing integers from a //! byte buffer. //! - Implementing a server protocol `IntProto` using this codec as a transport. //! - Implementing a service `Doubler` for doubling integers. //! - Spinning up this service on a local port (in `main`). //! //! ```no_run //! extern crate futures; //! extern crate tokio_core; //! extern crate tokio_proto; //! extern crate tokio_service; //! //! use std::str; //! use std::io::{self, ErrorKind, Write}; //! //! use futures::{future, Future, BoxFuture}; //! use tokio_core::io::{Io, Codec, Framed, EasyBuf}; //! use tokio_proto::TcpServer; //! use tokio_proto::pipeline::ServerProto; //! use tokio_service::Service; //! //! // First, we implement a *codec*, which provides a way of encoding and //! // decoding messages for the protocol. See the documentation for `Codec` in //! // `tokio-core` for more details on how that works. //! //! #[derive(Default)] //! pub struct IntCodec; //! //! fn parse_u64(from: &[u8]) -> Result<u64, io::Error> { //! Ok(str::from_utf8(from) //! .map_err(|e| io::Error::new(ErrorKind::InvalidData, e))? //! .parse() //! .map_err(|e| io::Error::new(ErrorKind::InvalidData, e))?) //! } //! //! impl Codec for IntCodec { //! type In = u64; //! type Out = u64; //! //! // Attempt to decode a message from the given buffer if a complete //! // message is available; returns `Ok(None)` if the buffer does not yet //! // hold a complete message. //! fn decode(&mut self, buf: &mut EasyBuf) -> Result<Option<u64>, io::Error> { //! if let Some(i) = buf.as_slice().iter().position(|&b| b == b'\n') { //! // remove the line, including the '\n', from the buffer //! let full_line = buf.drain_to(i + 1); //! //! // strip the'`\n' //! let slice = &full_line.as_slice()[..i]; //! //! Ok(Some(parse_u64(slice)?)) //! } else { //! Ok(None) //! } //! } //! //! // Attempt to decode a message assuming that the given buffer contains //! // *all* remaining input data. //! fn decode_eof(&mut self, buf: &mut EasyBuf) -> io::Result<u64> { //! let amt = buf.len(); //! Ok(parse_u64(buf.drain_to(amt).as_slice())?) //! } //! //! fn encode(&mut self, item: u64, into: &mut Vec<u8>) -> io::Result<()> { //! writeln!(into, "{}", item); //! Ok(()) //! } //! } //! //! // Next, we implement the server protocol, which just hooks up the codec above. //! //! pub struct IntProto; //! //! impl<T: Io + 'static> ServerProto<T> for IntProto { //! type Request = u64; //! type Response = u64; //! type Transport = Framed<T, IntCodec>; //! type BindTransport = Result<Self::Transport, io::Error>; //! //! fn bind_transport(&self, io: T) -> Self::BindTransport { //! Ok(io.framed(IntCodec)) //! } //! } //! //! // Now we implement a service we'd like to run on top of this protocol //! //! pub struct Doubler; //! //! impl Service for Doubler { //! type Request = u64; //! type Response = u64; //! type Error = io::Error; //! type Future = BoxFuture<u64, io::Error>; //! //! fn call(&self, req: u64) -> Self::Future { //! // Just return the request, doubled //! future::finished(req * 2).boxed() //! } //! } //! //! // Finally, we can actually host this service locally! //! fn main() { //! let addr = "0.0.0.0:12345".parse().unwrap(); //! TcpServer::new(IntProto, addr) //! .serve(|| Ok(Doubler)); //! } //! ``` #![doc(html_root_url = "https://docs.rs/tokio-proto/0.1")] #![deny(warnings, missing_docs, missing_debug_implementations)] #![allow(deprecated)] // TODO remove this extern crate net2; extern crate rand; extern crate slab; extern crate smallvec; extern crate take; extern crate tokio_core; extern crate tokio_io; extern crate tokio_service; #[macro_use] extern crate futures; #[macro_use] extern crate log; mod simple; pub use simple::{pipeline, multiplex}; pub mod streaming; pub mod util; mod tcp_client; pub use tcp_client::{TcpClient, Connect}; mod tcp_server; pub use tcp_server::TcpServer; use tokio_core::reactor::Handle; use tokio_service::Service; // TODO: move this into futures-rs mod buffer_one; /// Binds a service to an I/O object. /// /// This trait is not intended to be implemented directly; instead, implement /// one of the server protocol traits: /// /// - `pipeline::ServerProto` /// - `multiplex::ServerProto` /// - `streaming::pipeline::ServerProto` /// - `streaming::multiplex::ServerProto` /// /// See the crate documentation for more details on those traits. /// /// The `Kind` parameter, in particular, is a zero-sized type used to allow /// blanket implementation from the various protocol traits. Any additional /// implementations of this trait should use their own zero-sized kind type to /// distinguish them. pub trait BindServer<Kind, T: 'static>: 'static { /// The request type for the service. type ServiceRequest; /// The response type for the service. type ServiceResponse; /// The error type for the service. type ServiceError; /// Bind the service. /// /// This method should spawn a new task on the given event loop handle which /// provides the given service on the given I/O object. fn bind_server<S>(&self, handle: &Handle, io: T, service: S) where S: Service<Request = Self::ServiceRequest, Response = Self::ServiceResponse, Error = Self::ServiceError> + 'static; } /// Binds an I/O object as a client of a service. /// /// This trait is not intended to be implemented directly; instead, implement /// one of the server protocol traits: /// /// - `pipeline::ClientProto` /// - `multiplex::ClientProto` /// - `streaming::pipeline::ClientProto` /// - `streaming::multiplex::ClientProto` /// /// See the crate documentation for more details on those traits. /// /// The `Kind` parameter, in particular, is a zero-sized type used to allow /// blanket implementation from the various protocol traits. Any additional /// implementations of this trait should use their own zero-sized kind type to /// distinguish them. pub trait BindClient<Kind, T: 'static>: 'static { /// The request type for the service. type ServiceRequest; /// The response type for the service. type ServiceResponse; /// The error type for the service. type ServiceError; /// The bound service. type BindClient: Service<Request = Self::ServiceRequest, Response = Self::ServiceResponse, Error = Self::ServiceError>; /// Bind an I/O object as a service. fn bind_client(&self, handle: &Handle, io: T) -> Self::BindClient; }