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use ::async_std::sync::Mutex; use ::async_std::task; use cfg_if::cfg_if; use futures::channel::oneshot; use futures::{AsyncRead, AsyncWrite}; /// This module implements the traits/methods that require `async-std` /// runtime for the RPC client. The module is enabled if either /// `feature = "async_std_runtime"` or `featue = "http_tide"` is true. use std::sync::Arc; use super::*; type Codec = Arc<Mutex<Box<dyn ClientCodec>>>; type ResponseMap = HashMap<u16, oneshot::Sender<Result<ResponseBody, ResponseBody>>>; /// RPC Client. Unlike [`Server`](../../server/struct.Server.html), the `Client` /// struct contains field that uses runtime dependent synchronization primitives, /// thus there is a separate 'Client' struct defined for each of the `async-std` /// and `tokio` runtime. pub struct Client<Mode> { count: AtomicMessageId, inner_codec: Codec, pending: Arc<Mutex<ResponseMap>>, mode: PhantomData<Mode>, } cfg_if! { if #[cfg(any( all( feature = "serde_bincode", not(feature = "serde_json"), not(feature = "serde_cbor"), not(feature = "serde_rmp"), ), all( feature = "serde_cbor", not(feature = "serde_json"), not(feature = "serde_bincode"), not(feature = "serde_rmp"), ), all( feature = "serde_json", not(feature = "serde_bincode"), not(feature = "serde_cbor"), not(feature = "serde_rmp"), ), all( feature = "serde_rmp", not(feature = "serde_cbor"), not(feature = "serde_json"), not(feature = "serde_bincode"), ) ))] { use ::async_std::net::{TcpStream, ToSocketAddrs}; use async_tungstenite::async_std::connect_async; use crate::transport::ws::WebSocketConn; use crate::server::DEFAULT_RPC_PATH; /// The following impl block is controlled by feature flag. It is enabled /// if and only if **exactly one** of the the following feature flag is turned on /// - `serde_bincode` /// - `serde_json` /// - `serde_cbor` /// - `serde_rmp` impl Client<NotConnected> { /// Connects the an RPC server over socket at the specified network address /// /// This is enabled /// if and only if **exactly one** of the the following feature flag is turned on /// - `serde_bincode` /// - `serde_json` /// - `serde_cbor` /// - `serde_rmp` /// /// Example /// /// ```rust /// use toy_rpc::Client; /// /// #[async_std::main] /// async fn main() { /// let addr = "127.0.0.1"; /// let client = Client::dial(addr).await; /// } /// /// ``` pub async fn dial(addr: impl ToSocketAddrs) -> Result<Client<Connected>, Error> { let stream = TcpStream::connect(addr).await?; Ok(Self::with_stream(stream)) } /// Similar to `dial`, this connects to an WebSocket RPC server at the specified network address using the defatul codec /// /// This is enabled /// if and only if **exactly one** of the the following feature flag is turned on /// - `serde_bincode` /// - `serde_json` /// - `serde_cbor` /// - `serde_rmp` /// /// # Example /// /// ```rust /// use toy_rpc::client::Client; /// /// #[async_std::main] /// async fn main() { /// let addr = "ws://127.0.0.1:8080"; /// let client = Client::dial_http(addr).await.unwrap(); /// } /// ``` /// pub async fn dial_websocket(addr: &'static str) -> Result<Client<Connected>, Error> { let url = url::Url::parse(addr)?; Self::_dial_websocket(url).await } async fn _dial_websocket(url: url::Url) -> Result<Client<Connected>, Error> { let (ws_stream, _) = connect_async(&url).await?; let ws_stream = WebSocketConn::new(ws_stream); let codec = DefaultCodec::with_websocket(ws_stream); Ok(Self::with_codec(codec)) } /// Connects to an HTTP RPC server at the specified network address using WebSocket and the defatul codec. /// /// It is recommended to use "ws://" as the url scheme as opposed to "http://"; however, internally the url scheme /// is changed to "ws://". Internally, `DEFAULT_RPC_PATH="_rpc"` is appended to the end of `addr`, /// and the rest is the same is calling `dial_websocket`. /// If a network path were to be supplpied, the network path must end with a slash "/". /// For example, a valid path could be "ws://127.0.0.1/rpc/". /// /// *Warning*: WebSocket is used as the underlying transport protocol starting from version "0.5.0-beta.0", /// and this will make client of versions later than "0.5.0-beta.0" incompatible with servers of versions /// earlier than "0.5.0-beta.0". /// /// This is enabled /// if and only if **only one** of the the following feature flag is turned on /// - `serde_bincode` /// - `serde_json` /// - `serde_cbor` /// - `serde_rmp` /// /// # Example /// /// ```rust /// use toy_rpc::Client; /// /// #[async_std::main] /// async fn main() { /// let addr = "ws://127.0.0.1:8080/rpc/"; /// let client = Client::dial_http(addr).await.unwrap(); /// } /// ``` /// pub async fn dial_http(addr: &'static str) -> Result<Client<Connected>, Error> { let mut url = url::Url::parse(addr)?.join(DEFAULT_RPC_PATH)?; url.set_scheme("ws").expect("Failed to change scheme to ws"); Self::_dial_websocket(url).await } /// Creates an RPC `Client` over socket with a specified `async_std::net::TcpStream` and the default codec /// /// This is enabled /// if and only if **exactly one** of the the following feature flag is turned on /// - `serde_bincode` /// - `serde_json` /// - `serde_cbor` /// - `serde_rmp` /// /// # Example /// ``` /// use async_std::net::TcpStream; /// use toy_rpc::Client; /// /// #[async_std::main] /// async fn main() { /// let stream = TcpStream::connect("127.0.0.1:8080").await.unwrap(); /// let client = Client::with_stream(stream); /// } /// ``` pub fn with_stream<T>(stream: T) -> Client<Connected> where T: AsyncRead + AsyncWrite + Send + Sync + Unpin + 'static, { let codec = DefaultCodec::new(stream); Self::with_codec(codec) } } impl Client<NotConnected> { /// Creates an RPC 'Client` with a specified codec. The codec must /// implement `ClientCodec` trait and `GracefulShutdown` trait. /// /// Example /// /// ```rust /// use async_std::net::TcpStream; /// use toy_rpc::codec::bincode::Codec; /// use toy_rpc::Client; /// /// #[async_std::main] /// async fn main() { /// let addr = "127.0.0.1:8080"; /// let stream = TcpStream::connect(addr).await.unwrap(); /// let codec = Codec::new(stream); /// let client = Client::with_codec(codec); /// } /// ``` pub fn with_codec<C>(codec: C) -> Client<Connected> where C: ClientCodec + Send + Sync + 'static, { let box_codec: Box<dyn ClientCodec> = Box::new(codec); Client::<Connected> { count: AtomicMessageId::new(0u16), inner_codec: Arc::new(Mutex::new(box_codec)), pending: Arc::new(Mutex::new(HashMap::new())), mode: PhantomData, } } } } } impl Client<Connected> { /// Invokes the named function and wait synchronously in a blocking manner. /// /// This function internally calls `task::block_on` to wait for the response. /// Do NOT use this function inside another `task::block_on`.async_std /// /// Example /// /// ```rust /// use toy_rpc::Client; /// /// #[async_std::main] /// async fn main() { /// let addr = "127.0.0.1:8080"; /// let client = Client::dial(addr).await.unwrap(); /// /// let args = "arguments"; /// let reply: Result<String, Error> = client.call("echo_service.echo", &args); /// println!("{:?}", reply); /// } /// ``` pub fn call<Req, Res>(&self, service_method: impl ToString, args: Req) -> Result<Res, Error> where Req: serde::Serialize + Send + Sync, Res: serde::de::DeserializeOwned, { task::block_on(self.async_call(service_method, args)) } /// Invokes the named function asynchronously by spawning a new task and returns the `JoinHandle` /// /// ```rust /// use async_std::task; /// /// use toy_rpc::client::Client; /// use toy_rpc::error::Error; /// /// #[async_std::main] /// async fn main() { /// let addr = "127.0.0.1:8080"; /// let client = Client::dial(addr).await.unwrap(); /// /// let args = "arguments"; /// let handle: task::JoinHandle<Result<Res, Error>> = client.spawn_task("echo_service.echo", args); /// let reply: Result<String, Error> = handle.await; /// println!("{:?}", reply); /// } /// ``` pub fn spawn_task<Req, Res>( &self, service_method: impl ToString + Send + 'static, args: Req, ) -> task::JoinHandle<Result<Res, Error>> where Req: serde::Serialize + Send + Sync + 'static, Res: serde::de::DeserializeOwned + Send + 'static, { let codec = self.inner_codec.clone(); let pending = self.pending.clone(); let id = self.count.fetch_add(1u16, Ordering::Relaxed); task::spawn( async move { Self::_async_call(service_method, &args, id, codec, pending).await }, ) } /// Invokes the named function asynchronously /// /// Example /// /// ```rust /// use toy_rpc::Client; /// use toy_rpc::error::Error; /// /// #[async_std::main] /// async fn main() { /// let addr = "127.0.0.1:8080"; /// let client = Client::dial(addr).await.unwrap(); /// /// let args = "arguments"; /// let reply: Result<String, Error> = client.async_call("echo_service.echo", &args).await; /// println!("{:?}", reply); /// } /// ``` pub async fn async_call<Req, Res>( &self, service_method: impl ToString, args: Req, ) -> Result<Res, Error> where Req: serde::Serialize + Send + Sync, Res: serde::de::DeserializeOwned, { let codec = self.inner_codec.clone(); let pending = self.pending.clone(); let id = self.count.fetch_add(1u16, Ordering::Relaxed); Self::_async_call(service_method, &args, id, codec, pending).await } async fn _async_call<Req, Res>( service_method: impl ToString, args: &Req, id: MessageId, codec: Arc<Mutex<Box<dyn ClientCodec>>>, pending: Arc<Mutex<ResponseMap>>, ) -> Result<Res, Error> where Req: serde::Serialize + Send + Sync, Res: serde::de::DeserializeOwned, { let _codec = &mut *codec.lock().await; let header = RequestHeader { id, service_method: service_method.to_string(), }; let req = &args as &(dyn erased::Serialize + Send + Sync); // send request _codec.write_request(header, req).await?; // creates channel for receiving response let (done_sender, done) = oneshot::channel::<Result<ResponseBody, ResponseBody>>(); // insert sender to pending map { let mut _pending = pending.lock().await; _pending.insert(id, done_sender); } Client::<Connected>::_read_response(_codec.as_mut(), pending).await?; Client::<Connected>::_handle_response(done, &id) } /// Gracefully shutdown the connection. /// /// For a WebSocket connection, a Close message will be sent. /// For a raw TCP connection, the client will simply drop the connection pub async fn close(self) { let _codec = &mut self.inner_codec.lock().await; _codec.close().await; } } impl Client<Connected> { async fn _read_response( codec: &mut dyn ClientCodec, pending: Arc<Mutex<ResponseMap>>, ) -> Result<(), Error> { // wait for response if let Some(header) = codec.read_response_header().await { let ResponseHeader { id, is_error } = header?; let deserializer = codec .read_response_body() .await .ok_or(Error::IoError(std::io::Error::new( std::io::ErrorKind::UnexpectedEof, "Unexpected EOF reading response body", )))?; let deserializer = deserializer?; let res = match is_error { false => Ok(deserializer), true => Err(deserializer), }; // send back response let mut _pending = pending.lock().await; if let Some(done_sender) = _pending.remove(&id) { done_sender.send(res).map_err(|_| { Error::TransportError(format!( "Failed to send ResponseBody over oneshot channel {}", &id )) })?; } } Ok(()) } fn _handle_response<Res>( mut done: oneshot::Receiver<Result<ResponseBody, ResponseBody>>, id: &MessageId, ) -> Result<Res, Error> where Res: serde::de::DeserializeOwned, { // wait for result from oneshot channel let res = match done.try_recv() { Ok(o) => match o { Some(r) => r, None => { return Err(Error::TransportError(format!( "Done channel for id {} is out of date", &id ))) } }, _ => { return Err(Error::TransportError(format!( "Done channel for id {} is canceled", &id ))) } }; // deserialize Ok message and Err message match res { Ok(mut resp_body) => { let resp = erased::deserialize(&mut resp_body) .map_err(|e| Error::ParseError(Box::new(e)))?; // upon successful deserializing, an Ok() must be returned Ok(resp) } Err(mut err_body) => { let err = erased::deserialize(&mut err_body) .map_err(|e| Error::ParseError(Box::new(e)))?; // upon successful deserializing, an Err() must be returned Err(Error::RpcError(err)) } } } }