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// Copyright 2019 Google LLC // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // https://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. // //! # Send Descriptors //! //! *Send Descriptors* are types that implement [`SendDesc`] that can be passed to the `send*` //! methods of [`LocalEndpoint`] and [`RemoteEndpoint`]. They define almost every aspect of how //! a message transaction is handled. //! //! Typical usage of this crate does not require writing implementing [`SendDesc`] by hand, //! although you could certainly do so if needed. //! Instead, `SyncDesc` instances are easily constructed using *combinators*. //! //! ## Example //! //! Here we create a `SendDesc` instance that just sends a GET request and waits for a response: //! //! ``` //! # #![feature(async_await)] //! # use std::sync::Arc; //! # use futures::{prelude::*,executor::LocalPool,task::LocalSpawnExt}; //! # use async_coap::prelude::*; //! # use async_coap::datagram::{DatagramLocalEndpoint, AllowStdUdpSocket, LoopbackSocket}; //! # use async_coap::null::NullLocalEndpoint; //! # let socket = AllowStdUdpSocket::bind("[::]:0").expect("UDP bind failed"); //! # let local_endpoint = Arc::new(DatagramLocalEndpoint::new(socket)); //! # let mut pool = LocalPool::new(); //! # pool.spawner().spawn_local(local_endpoint.clone().receive_loop_arc(null_receiver!()).map(|_|unreachable!())); //! # let future = async move { //! # //! let mut remote_endpoint = local_endpoint //! .remote_endpoint_from_uri(uri!("coap://coap.me:5683/test")) //! .expect("Remote endpoint lookup failed"); //! //! let future = remote_endpoint.send(CoapRequest::get()); //! //! assert_eq!(future.await, Ok(())); //! # //! # //! # }; //! # pool.run_until(future); //! ``` //! //! That `SendDesc` was perhaps a little *too* simple: it doesn't even interpret the results, //! returning `Ok(())` for any message responding with a `2.05 Content` message! //! //! By using the combinator `.emit_successful_response()`, we can have our `SendDesc` return //! an owned copy of the message it received ([`OwnedImmutableMessage`](crate::message::OwnedImmutableMessage)): //! //! ``` //! # #![feature(async_await)] //! # use std::sync::Arc; //! # use futures::{prelude::*,executor::LocalPool,task::LocalSpawnExt}; //! # use async_coap::prelude::*; //! # use async_coap::datagram::{DatagramLocalEndpoint, AllowStdUdpSocket, LoopbackSocket}; //! # let socket = AllowStdUdpSocket::bind("[::]:0").expect("UDP bind failed"); //! # let local_endpoint = Arc::new(DatagramLocalEndpoint::new(socket)); //! # let mut pool = LocalPool::new(); //! # pool.spawner().spawn_local(local_endpoint.clone().receive_loop_arc(null_receiver!()).map(|_|unreachable!())); //! # let future = async move { //! # use async_coap::message::OwnedImmutableMessage; //! # let mut remote_endpoint = local_endpoint //! # .remote_endpoint_from_uri(uri!("coap://coap.me:5683/test")) //! # .expect("Remote endpoint lookup failed"); //! # //! # //! let send_desc = CoapRequest::get().emit_successful_response(); //! //! let future = remote_endpoint.send(send_desc); //! //! let message = future.await.expect("Request failed"); //! //! println!("Got reply: {:?}", message); //! # //! # //! # }; //! # pool.run_until(future); //! ``` //! //! What if we wanted the response in JSON? What if it was really large and we //! knew we would need to do a block2 transfer? We can do that easily: //! //! ```ignore //! let send_desc = CoapRequest::get() //! .accept(ContentFormat::APPLICATION_JSON) //! .block2(None) //! .emit_successful_collected_response(); //! //! // Here we are specifying that we want to send the request to a specific //! // path on the remote endpoint, `/large` in this case. //! let future = remote_endpoint.send_to(rel_ref!("/large"), send_desc); //! //! let message = future.await.expect("Request failed"); //! //! println!("Got reply: {:?}", message); //! ``` //! //! But if this is a large amount of data, we won't get any indication about the transfer //! until it is done. What if we wanted to add some printouts about the status? //! //! ```ignore //! let send_desc = CoapRequest::get() //! .accept(ContentFormat::APPLICATION_JSON) //! .block2(None) //! .emit_successful_collected_response() //! .inspect(|context| { //! let addr = context.remote_address(); //! let msg = context.message(); //! //! // Print out each individual block message received. //! println!("Got {:?} from {}", msg, addr); //! }); //! //! let future = remote_endpoint.send_to(rel_ref!("/large"), send_desc); //! //! let message = future.await.expect("Request failed"); //! //! println!("Got reply: {:?}", message); //! ``` //! //! There are [many more combinators][SendDescExt] for doing all sorts of things, such as //! adding additional options and [block2 message aggregation](SendDescUnicast::block2). use super::*; mod request; pub use request::*; mod observe; pub use observe::*; mod unicast_block2; pub use unicast_block2::*; mod handler; pub use handler::*; mod inspect; pub use inspect::*; mod payload; pub use payload::*; mod ping; pub use ping::Ping; mod add_option; pub use add_option::*; mod nonconfirmable; pub use nonconfirmable::*; mod multicast; pub use multicast::*; mod emit; pub use emit::*; mod include_socket_addr; pub use include_socket_addr::*; mod uri_host_path; pub use uri_host_path::UriHostPath; use std::iter::{once, Once}; use std::marker::PhantomData; use std::ops::Bound; use std::time::Duration; /// # Send Descriptor Trait /// /// Types implementing this trait can be passed to the `send*` methods of [`LocalEndpoint`] /// and [`RemoteEndpoint`], and can define almost every aspect of how a message transaction /// is handled. /// /// See the [module level documentation](index.html) for more information on typical usage /// patterns. /// /// ## Internals /// /// There are several methods in this trait, but three of them are critical: /// /// * [`write_options`](SendDesc::write_options)\: Defines which options are going to be /// included in the outbound message. /// * [`write_payload`](SendDesc::write_payload)\: Defines the contents of the payload for the /// outbound message. /// * [`handler`](SendDesc::handler)\: Handles inbound reply messages, as well as error conditions. /// pub trait SendDesc<IC, R = (), TP = StandardCoapConstants>: Send where IC: InboundContext, R: Send, TP: TransParams, { /// **Experimental**: Gets custom transmission parameters. fn trans_params(&self) -> Option<TP> { None } /// **Experimental**: Used for determining if the given option seen in the reply message /// is supported or not. /// /// Response messages with any options that cause this /// method to return false will be rejected. /// fn supports_option(&self, option: OptionNumber) -> bool { !option.is_critical() } /// Calculates the duration of the delay to wait before sending the next retransmission. /// /// If `None` is returned, then no further retransmissions will be attempted. fn delay_to_retransmit(&self, retransmits_sent: u32) -> Option<Duration> { if retransmits_sent > TP::COAP_MAX_RETRANSMIT { return None; } let ret = (TP::COAP_ACK_TIMEOUT.as_millis() as u64) << retransmits_sent as u64; const JDIV: u64 = 512u64; let rmod: u64 = (JDIV as f32 * (TP::COAP_ACK_RANDOM_FACTOR - 1.0)) as u64; let jmul = JDIV + rand::random::<u64>() % rmod; Some(Duration::from_millis(ret * jmul / JDIV)) } /// The delay to wait between when we have received a successful response and when /// we should send out another request. /// /// The new request will have a new msg_id, but /// the same token. The retransmission counter will be reset to zero. /// /// This mechanism is currently used exclusively for CoAP observing. /// /// The default return value is `None`, indicating that there are to be no message /// restarts. fn delay_to_restart(&self) -> Option<Duration> { None } /// The maximum time to wait for an asynchronous response after having received an ACK. fn max_rtt(&self) -> Duration { TP::COAP_MAX_RTT } /// the maximum time from the first transmission of a Confirmable message to the time when /// the sender gives up on receiving an acknowledgement or reset. fn transmit_wait_duration(&self) -> Duration { TP::COAP_MAX_TRANSMIT_WAIT } /// Defines which options are going to be included in the outbound message. /// /// Writes all options in the given range to `msg`. fn write_options( &self, msg: &mut dyn OptionInsert, socket_addr: &IC::SocketAddr, start: Bound<OptionNumber>, end: Bound<OptionNumber>, ) -> Result<(), Error>; /// Generates the outbound message by making calls into `msg`. fn write_payload( &self, msg: &mut dyn MessageWrite, socket_addr: &IC::SocketAddr, ) -> Result<(), Error>; /// Handles the response to the outbound message. fn handler(&mut self, context: Result<&IC, Error>) -> Result<ResponseStatus<R>, Error>; } /// Marker trait for identifying that this `SendDesc` is for *unicast* requests. /// Also contains unicast-specific combinators, such as [`block2()`][SendDescUnicast::block2]. pub trait SendDescUnicast { /// Returns a send descriptor that will perform Block2 processing. /// /// Note that just adding this to your send descriptor chain alone is unlikely to do what /// you want. You've got three options: /// /// * Add a call to [`emit_successful_collected_response`][UnicastBlock2::emit_successful_collected_response] /// immediately after the call to this method. This will cause the message to be reconstructed from the blocks /// and returned as a value from the future from `send`. You can optionally add an /// [`inspect`][SendDescExt::inspect] combinator to get some feedback as the message is being /// reconstructed from all of the individual block messages. /// * Add a call to [`emit_successful_response`][SendDescExt::emit_successful_response] along /// with using `send_to_stream` instead of `send`. This will give you a `Stream` that will /// contain all of the individual block messages in the stream. /// * [Add your own handler][SendDescExt::use_handler] to do whatever you need to do, returning /// `ResponseStatus::SendNext` until all of the blocks have been received. This is /// useful if you want to avoid memory allocation. /// /// There may be other valid combinations of combinators, depending on what you are trying /// to do. fn block2<IC, R, TP>(self, block2: Option<BlockInfo>) -> UnicastBlock2<Self, IC> where IC: InboundContext, R: Send, TP: TransParams, Self: SendDesc<IC, R, TP> + Sized, { UnicastBlock2::new(self, block2) } } /// Marker trait for identifying that this `SendDesc` is for *multicast* requests. /// Also contains multicast-specific extensions. pub trait SendDescMulticast {} /// Combinator extension trait for Send Descriptors. pub trait SendDescExt<IC, R, TP>: SendDesc<IC, R, TP> + Sized where IC: InboundContext, R: Send, TP: TransParams, { /// Adds zero or more instances of the option `key`, using values coming from `viter`. /// /// This method allows you to conditionally add options to a send descriptor. For example, /// you could convert an `Option` to an iterator (using `into_iterator()`) and pass it to /// this method: if the `Option` is `None` then no coap option will be added. fn add_option_iter<K, I>(self, key: OptionKey<K>, viter: I) -> AddOption<Self, K, I, IC> where I: IntoIterator<Item = K> + Send + Clone, K: Send + Clone, { AddOption { inner: self, key, viter, phantom: PhantomData, } } /// Adds one instance of the option `key` with a value of `value`. fn add_option<K>(self, key: OptionKey<K>, value: K) -> AddOption<Self, K, Once<K>, IC> where K: Send + Clone, { self.add_option_iter(key, once(value)) } /// Adds an Accept option with the given `ContentFormat`. fn accept( self, accept: ContentFormat, ) -> AddOption<Self, ContentFormat, Once<ContentFormat>, IC> { self.add_option(option::ACCEPT, accept) } /// Adds an Content-Format option with the given `ContentFormat`. fn content_format( self, content_format: ContentFormat, ) -> AddOption<Self, ContentFormat, Once<ContentFormat>, IC> { self.add_option(option::CONTENT_FORMAT, content_format) } /// Adds a handler function to be called when a response message has been received (or when /// an error has occurred). fn use_handler<F, FR>(self, handler: F) -> Handler<Self, F> where F: FnMut( Result<&dyn InboundContext<SocketAddr = IC::SocketAddr>, Error>, ) -> Result<ResponseStatus<FR>, Error> + Send, FR: Send, { Handler { inner: self, handler, } } /// Updates the send descriptor chain to emit any received message as a result, even /// if that message has a message code that indicates an error. fn emit_any_response(self) -> EmitAnyResponse<Self> { EmitAnyResponse::new(self) } /// Updates the send descriptor chain to emit received message as a result, but only /// if that message has a message code that indicates success. fn emit_successful_response(self) -> EmitSuccessfulResponse<Self> { EmitSuccessfulResponse::new(self) } /// Updates the send descriptor chain to emit only the message code of the received /// response. fn emit_msg_code(self) -> EmitMsgCode<Self> { EmitMsgCode::new(self) } /// Updates the send descriptor chain to also emit the SocketAddr of the sender /// of the response, resulting in tuple return type. /// /// This is useful for handling responses to a multicast request. fn include_socket_addr(self) -> IncludeSocketAddr<Self> { IncludeSocketAddr::new(self) } /// Adds an inspection closure that will be called for each received response message. /// /// The inspector closure will not be called if no responses are received, and it cannot /// change the behavior of the send descriptor chain. If you need either of those /// behaviors, see [`SendDescExt::use_handler`]. fn inspect<F>(self, inspect: F) -> Inspect<Self, F> where F: FnMut(&dyn InboundContext<SocketAddr = IC::SocketAddr>) + Send, { Inspect { inner: self, inspect, } } /// Adds a closure that writes to the payload of the outbound message. fn payload_writer<F>(self, writer: F) -> PayloadWriter<Self, F> where F: Fn(&mut dyn MessageWrite) -> Result<(), Error> + Send, { PayloadWriter { inner: self, writer, } } /// Allows you to specify the URI_HOST, URI_PATH, and URI_QUERY option values /// in a more convenient way than using `add_option_iter` manually. fn uri_host_path<T: Into<RelRefBuf>>( self, host: Option<String>, uri_path: T, ) -> UriHostPath<Self, IC> { UriHostPath { inner: self, host, path_and_query: uri_path.into(), phantom: PhantomData, } } } /// Blanket implementation of `SendDescExt` for all types implementing `SendDesc`. impl<T, IC, R, TP> SendDescExt<IC, R, TP> for T where T: SendDesc<IC, R, TP>, IC: InboundContext, R: Send, TP: TransParams, { } /// Helper macro that assists with writing correct implementations of [`SendDesc::write_options`]. /// /// ## Example /// /// ``` /// # use async_coap::uri::RelRefBuf; /// # use std::marker::PhantomData; /// # use async_coap::send_desc::SendDesc; /// # use async_coap::prelude::*; /// # use async_coap::write_options; /// # use async_coap::{InboundContext, Error, message::MessageWrite}; /// # use std::ops::Bound; /// # pub struct WriteOptionsExample<IC>(PhantomData<IC>); /// # impl<IC: InboundContext> SendDesc<IC, ()> for WriteOptionsExample<IC> { /// # /// fn write_options( /// &self, /// msg: &mut dyn OptionInsert, /// socket_addr: &IC::SocketAddr, /// start: Bound<OptionNumber>, /// end: Bound<OptionNumber>, /// ) -> Result<(), Error> { /// write_options!((msg, socket_addr, start, end) { /// // Note that the options **MUST** be listed **in numerical order**, /// // otherwise the behavior will be undefined! /// URI_HOST => Some("example.com").into_iter(), /// URI_PORT => Some(1234).into_iter(), /// URI_PATH => vec!["a","b","c"].into_iter(), /// }) /// } /// # /// # fn write_payload(&self,msg: &mut dyn MessageWrite, socket_addr: &IC::SocketAddr) -> Result<(), Error> { /// # Ok(()) /// # } /// # fn handler(&mut self,context: Result<&IC, Error>) -> Result<ResponseStatus<()>, Error> { /// # context.map(|_| ResponseStatus::Done(())) /// # } /// # } /// ``` #[macro_export] macro_rules! write_options { (($msg:expr, $socket_addr:expr, $start:expr, $end:expr, $inner:expr) { $($key:expr => $viter:expr),* }) => {{ let mut start = $start; let end = $end; let inner = &$inner; let msg = $msg; let socket_addr = $socket_addr; #[allow(unused)] use $crate::option::*; #[allow(unused)] use std::iter::once; $( write_options!(_internal $key, $viter, start, end, msg, socket_addr, inner); )* inner.write_options(msg, socket_addr, start, end) }}; (($msg:expr, $socket_addr:expr, $start:expr, $end:expr) { $($key:expr => $viter:expr),* }) => {{ let mut start = $start; let end = $end; let msg = $msg; let _socket_addr = $socket_addr; #[allow(unused)] use $crate::option::*; #[allow(unused)] use std::iter::once; $( write_options!(_internal $key, $viter, start, end, msg, socket_addr); )* let _ = start; Ok(()) }}; (($msg:ident, $socket_addr:ident, $start:ident, $end:ident, $inner:expr) { $($key:expr => $viter:expr),* ,}) => { write_options!(($msg,$socket_addr,$start,$end,$inner){$($key=>$viter),*}) }; (($msg:ident, $socket_addr:ident, $start:ident, $end:ident) { $($key:expr => $viter:expr),* ,}) => { write_options!(($msg,$socket_addr,$start,$end){$($key=>$viter),*}) }; ( _internal $key:expr, $viter:expr, $start:ident, $end:ident, $msg:ident, $socket_addr:ident, $inner:expr) => {{ let key = $key; let mut value_iter = $viter.into_iter().peekable(); if value_iter.peek().is_some() && match $start { Bound::Included(b) => b <= key.0, Bound::Excluded(b) => b < key.0, Bound::Unbounded => true, } { if match $end { Bound::Included(b) => key.0 <= b, Bound::Excluded(b) => key.0 < b, Bound::Unbounded => true, } { $inner.write_options($msg, $socket_addr, $start, Bound::Included(key.0))?; for value in value_iter { $msg.insert_option(key, value)?; } $start = Bound::Excluded(key.0) } } }}; ( _internal $key:expr, $viter:expr, $start:ident, $end:ident, $msg:ident, $socket_addr:ident) => {{ let key = $key; let mut value_iter = $viter.into_iter().peekable(); if value_iter.peek().is_some() && match $start { Bound::Included(b) => b <= key.0, Bound::Excluded(b) => b < key.0, Bound::Unbounded => true, } { if match $end { Bound::Included(b) => key.0 <= b, Bound::Excluded(b) => key.0 < b, Bound::Unbounded => true, } { for value in value_iter { $msg.insert_option(key, value)?; } $start = Bound::Excluded(key.0) } } }}; } /// Helper macro that provides pass-thru implementations of the timing-related methods /// of a [`SendDesc`]. /// /// This macro takes a single argument: the name of the member variable to pass along /// the call to. #[doc(hidden)] #[macro_export] macro_rules! send_desc_passthru_timing { ($inner:tt) => { fn delay_to_retransmit(&self, retransmits_sent: u32) -> Option<::core::time::Duration> { self.$inner.delay_to_retransmit(retransmits_sent) } fn delay_to_restart(&self) -> Option<::core::time::Duration> { self.$inner.delay_to_restart() } fn max_rtt(&self) -> ::core::time::Duration { self.$inner.max_rtt() } fn transmit_wait_duration(&self) -> ::core::time::Duration { self.$inner.transmit_wait_duration() } } } /// Helper macro that provides pass-thru implementation of [`SendDesc::write_options`]. /// /// This macro takes a single argument: the name of the member variable to pass along /// the call to. #[doc(hidden)] #[macro_export] macro_rules! send_desc_passthru_options { ($inner:tt) => { fn write_options( &self, msg: &mut dyn OptionInsert, socket_addr: &IC::SocketAddr, start: Bound<OptionNumber>, end: Bound<OptionNumber>, ) -> Result<(), Error> { self.$inner.write_options(msg, socket_addr, start, end) } } } /// Helper macro that provides pass-thru implementations of [`SendDesc::handler`] and /// [`SendDesc::supports_option`]. /// /// This macro takes a single argument: the name of the member variable to pass along /// the call to. #[doc(hidden)] #[macro_export] macro_rules! send_desc_passthru_handler { ($inner:tt, $rt:ty) => { fn supports_option(&self, option: OptionNumber) -> bool { self.$inner.supports_option(option) } fn handler(&mut self, context: Result<&IC, Error>) -> Result<ResponseStatus<$rt>, Error> { self.$inner.handler(context) } }; ($inner:tt) => { send_desc_passthru_handler!($inner, ()); } } /// Helper macro that provides pass-thru implementation of [`SendDesc::supports_option`]. /// /// This macro takes a single argument: the name of the member variable to pass along /// the call to. #[doc(hidden)] #[macro_export] macro_rules! send_desc_passthru_supports_option { ($inner:tt) => { fn supports_option(&self, option: OptionNumber) -> bool { self.$inner.supports_option(option) } } } /// Helper macro that provides pass-thru implementation of [`SendDesc::write_payload`]. /// /// This macro takes a single argument: the name of the member variable to pass along /// the call to. #[doc(hidden)] #[macro_export] macro_rules! send_desc_passthru_payload { ($inner:tt) => { fn write_payload( &self, msg: &mut dyn MessageWrite, socket_addr: &IC::SocketAddr, ) -> Result<(), Error> { self.$inner.write_payload(msg, socket_addr) } } }