betfair_stream_api/
lib.rs

1//! Betfair Stream API client implementation.
2//!
3//! This crate provides an asynchronous client for interacting with Betfair's Streaming API.
4//! It manages connection setup, handshake, framing, heartbeats, and automatic reconnections.
5//! Users can customize how incoming messages are handled by implementing the `MessageProcessor` trait
6//! or using the built-in `Cache` processor for maintaining market and order caches.
7extern crate alloc;
8pub mod cache;
9use backon::{BackoffBuilder as _, ExponentialBuilder};
10use betfair_adapter::{Authenticated, BetfairRpcClient, Unauthenticated};
11pub use betfair_stream_types as types;
12use betfair_stream_types::{
13    request::{RequestMessage, authentication_message, heartbeat_message::HeartbeatMessage},
14    response::{
15        ResponseMessage,
16        connection_message::ConnectionMessage,
17        status_message::{ErrorCode, StatusMessage},
18    },
19};
20use cache::{
21    primitives::{MarketBookCache, OrderBookCache},
22    tracker::StreamState,
23};
24use core::fmt;
25use core::{pin::pin, time::Duration};
26use eyre::Context as _;
27use futures::{
28    SinkExt as _, StreamExt as _,
29    future::{self, select},
30};
31use std::sync::Arc;
32use tokio::{
33    net::TcpStream,
34    sync::mpsc::{self, Receiver, Sender},
35    task::JoinHandle,
36    time::sleep,
37};
38use tokio_stream::wrappers::{IntervalStream, ReceiverStream};
39use tokio_util::{
40    bytes,
41    codec::{Decoder, Encoder, Framed},
42};
43
44/// A Betfair Stream API client that handles connection, handshake, incoming/outgoing messages,
45/// heartbeat and automatic reconnects.
46/// Builder for creating a Betfair Streaming API client.
47///
48/// # Type Parameters
49///
50/// - `T`: A type that implements `MessageProcessor`, used to handle incoming `ResponseMessage` objects.
51#[derive(Debug, Clone)]
52pub struct BetfairStreamBuilder<T: MessageProcessor> {
53    /// betfair client
54    pub client: BetfairRpcClient<Unauthenticated>,
55    /// Heartbeat interval (used only if heartbeat_enabled is true)
56    pub heartbeat_interval: Option<Duration>,
57    /// The intermediate processor of messages
58    pub processor: T,
59}
60
61/// Handle to a running Betfair Streaming API client.
62///
63/// Provides channels to send requests (`send_to_stream`) and receive processed messages (`sink`).
64#[derive(Debug)]
65pub struct BetfairStreamClient<T: MessageProcessor> {
66    /// send a message to the Betfair stream
67    pub send_to_stream: Sender<RequestMessage>,
68    /// Receive a message from the stream
69    pub sink: Receiver<T::Output>,
70}
71
72/// Default `MessageProcessor` implementation that maintains market and order caches.
73///
74/// It updates an internal `StreamState` to apply incremental updates to market and order books.
75#[derive(Debug, Clone)]
76pub struct Cache {
77    state: StreamState,
78}
79
80/// Variants of messages produced by the cache-based processor.
81///
82/// `CachedMessage` represents high-level events derived from raw Betfair streaming responses,
83/// enriched with internal cache state for market and order books.
84#[derive(Debug, Clone, PartialEq, Eq)]
85pub enum CachedMessage {
86    /// A connection handshake message received from the stream,
87    /// containing connection ID and related metadata.
88    /// Also returned on heartbeat messages.
89    Connection(ConnectionMessage),
90
91    /// A batch of market book updates, each describing the current state or changes of a market.
92    MarketChange(Vec<MarketBookCache>),
93
94    /// A batch of order book updates, representing new orders, matched orders,
95    /// and cancellations in the order cache.
96    OrderChange(Vec<OrderBookCache>),
97
98    /// A status message from the stream, used for heartbeats,
99    /// subscription confirmations, or error notifications.
100    Status(StatusMessage),
101}
102
103impl MessageProcessor for Cache {
104    type Output = CachedMessage;
105
106    fn process_message(&mut self, message: ResponseMessage) -> Option<Self::Output> {
107        match message {
108            ResponseMessage::Connection(connection_message) => {
109                Some(CachedMessage::Connection(connection_message))
110            }
111            ResponseMessage::MarketChange(market_change_message) => {
112                let data = self
113                    .state
114                    .market_change_update(market_change_message)
115                    .map(|markets| markets.into_iter().cloned().collect::<Vec<_>>())
116                    .map(CachedMessage::MarketChange);
117
118                data
119            }
120            ResponseMessage::OrderChange(order_change_message) => {
121                let data = self
122                    .state
123                    .order_change_update(order_change_message)
124                    .map(|markets| markets.into_iter().cloned().collect::<Vec<_>>())
125                    .map(CachedMessage::OrderChange);
126
127                data
128            }
129            ResponseMessage::Status(status_message) => Some(CachedMessage::Status(status_message)),
130        }
131    }
132}
133
134/// `MessageProcessor` that forwards raw `ResponseMessage` objects without transformation.
135#[derive(Debug)]
136pub struct Forwarder;
137impl MessageProcessor for Forwarder {
138    type Output = ResponseMessage;
139
140    fn process_message(&mut self, message: ResponseMessage) -> Option<Self::Output> {
141        Some(message)
142    }
143}
144/// Trait for processing incoming Betfair streaming `ResponseMessage` objects into user-defined outputs.
145///
146/// Implementers can filter or transform messages and control which messages are forwarded to the client sink.
147pub trait MessageProcessor: Send + Sync + 'static {
148    /// The processed message type produced by `process_message`
149    type Output: Send + Clone + Sync + 'static + core::fmt::Debug;
150
151    /// Process an incoming `ResponseMessage`.
152    ///
153    /// Returns `Some(Output)` to forward a processed message, or `None` to drop it.
154    fn process_message(&mut self, message: ResponseMessage) -> Option<Self::Output>;
155}
156
157impl<T: MessageProcessor> BetfairStreamBuilder<T> {
158    /// Creates a new `BetfairStreamBuilder` with the given authenticated RPC client.
159    ///
160    /// Uses the default `Cache` message processor to maintain market and order caches.
161    /// By default, no heartbeat messages are sent.
162    ///
163    /// # Parameters
164    ///
165    /// * `client` - An authenticated Betfair RPC client for establishing the streaming connection.
166    ///
167    /// # Returns
168    ///
169    /// A `BetfairStreamBuilder` configured with cache-based message processing.
170    pub fn new(client: BetfairRpcClient<Unauthenticated>) -> BetfairStreamBuilder<Cache> {
171        BetfairStreamBuilder {
172            client,
173            heartbeat_interval: None,
174            processor: Cache {
175                state: StreamState::new(),
176            },
177        }
178    }
179
180    /// Creates a new `BetfairStreamBuilder` with raw message forwarding.
181    ///
182    /// Uses the `Forwarder` message processor to forward raw `ResponseMessage` objects without caching.
183    /// By default, no heartbeat messages are sent.
184    ///
185    /// # Parameters
186    ///
187    /// * `client` - An authenticated Betfair RPC client for establishing the streaming connection.
188    ///
189    /// # Returns
190    ///
191    /// A `BetfairStreamBuilder` configured to forward raw messages.
192    pub fn new_without_cache(
193        client: BetfairRpcClient<Unauthenticated>,
194    ) -> BetfairStreamBuilder<Forwarder> {
195        BetfairStreamBuilder {
196            client,
197            heartbeat_interval: None,
198            processor: Forwarder,
199        }
200    }
201
202    /// Enables periodic heartbeat messages to keep the streaming connection alive.
203    ///
204    /// # Parameters
205    ///
206    /// * `interval` - The duration between heartbeat messages.
207    ///
208    /// # Returns
209    ///
210    /// The updated `BetfairStreamBuilder` with heartbeat enabled.
211    pub fn with_heartbeat(mut self, interval: Duration) -> Self {
212        self.heartbeat_interval = Some(interval);
213        self
214    }
215
216    /// Starts the Betfair streaming client and returns handles for interaction.
217    ///
218    /// This will spawn an asynchronous task that manages the connection, handshake,
219    /// incoming/outgoing messages, heartbeats (if enabled), and automatic reconnections.
220    ///
221    /// # Returns
222    ///
223    /// * `BetfairStreamClient<T>` - A client handle providing:
224    ///     - `send_to_stream`: a channel sender for outgoing `RequestMessage`s.
225    ///     - `sink`: a channel receiver for processed messages of type `T::Output`.
226    /// * `JoinHandle<eyre::Result<()>>` - A handle to the background task driving the streaming logic.
227    pub async fn start(self) -> (BetfairStreamClient<T>, JoinHandle<eyre::Result<()>>) {
228        let (to_stream_tx, to_stream_rx) = mpsc::channel(100);
229        let (from_stream_tx, from_stream_rx) = mpsc::channel(100);
230
231        let task = tokio::task::spawn(self.run(from_stream_tx, to_stream_rx));
232
233        (
234            BetfairStreamClient {
235                send_to_stream: to_stream_tx,
236                sink: from_stream_rx,
237            },
238            task,
239        )
240    }
241
242    async fn run(
243        self,
244        from_stream_tx: Sender<T::Output>,
245        to_stream_rx: Receiver<RequestMessage>,
246    ) -> eyre::Result<()> {
247        if let Some(hb) = self.heartbeat_interval {
248            let heartbeat_stream = {
249                let mut interval = tokio::time::interval(hb);
250                interval.reset();
251                let interval_stream = IntervalStream::new(interval).fuse();
252                interval_stream
253                    .map(move |instant| HeartbeatMessage {
254                        id: Some(
255                            instant
256                                .into_std()
257                                .elapsed()
258                                .as_secs()
259                                .try_into()
260                                .unwrap_or_default(),
261                        ),
262                    })
263                    .map(RequestMessage::Heartbeat)
264                    .boxed()
265            };
266            let input_stream = futures::stream::select_all([
267                heartbeat_stream,
268                ReceiverStream::new(to_stream_rx).boxed(),
269            ]);
270
271            self.run_base(from_stream_tx, input_stream).await
272        } else {
273            self.run_base(from_stream_tx, ReceiverStream::new(to_stream_rx))
274                .await
275        }
276    }
277
278    async fn run_base(
279        mut self,
280        mut from_stream_tx: Sender<T::Output>,
281        mut to_stream_rx: impl futures::Stream<Item = RequestMessage> + Unpin,
282    ) -> eyre::Result<()> {
283        let (mut client, _) = self.client.clone().authenticate().await?;
284        let mut backoff = ExponentialBuilder::new().build();
285        let mut first_call = true;
286        'retry: loop {
287            if !first_call {
288                // add exponential recovery
289                let Some(delay) = backoff.next() else {
290                    eyre::bail!("connection retry attempts exceeded")
291                };
292                sleep(delay).await;
293            }
294            first_call = true;
295
296            // Connect (with handshake) using retry logic.
297            let mut stream = self
298                .connect_with_retry(&mut from_stream_tx, &mut client)
299                .await?;
300            tracing::info!("Connected to {}", self.client.stream.url());
301
302            loop {
303                let stream_next = pin!(stream.next());
304                let to_stream_rx_next = pin!(to_stream_rx.next());
305                match select(to_stream_rx_next, stream_next).await {
306                    future::Either::Left((request, _)) => {
307                        let Some(request) = request else {
308                            tracing::warn!("request returned None");
309                            continue 'retry;
310                        };
311
312                        tracing::debug!(?request, "sending to betfair");
313                        let Ok(()) = stream.send(request).await else {
314                            tracing::warn!("could not send request to stream");
315                            continue 'retry;
316                        };
317                    }
318                    future::Either::Right((message, _)) => {
319                        let Some(message) = message else {
320                            tracing::warn!("stream returned None");
321                            continue 'retry;
322                        };
323
324                        match message {
325                            Ok(message) => {
326                                let message = self.processor.process_message(message);
327                                tracing::debug!(?message, "received from betfair");
328                                let Some(message) = message else {
329                                    continue;
330                                };
331
332                                let Ok(()) = from_stream_tx.send(message).await else {
333                                    tracing::warn!("could not send stream message to sink");
334                                    continue 'retry;
335                                };
336                            }
337                            Err(err) => tracing::warn!(?err, "reading message error"),
338                        }
339                    }
340                }
341            }
342        }
343    }
344
345    /// Attempt to connect and perform a handshake using exponential backoff.
346    #[tracing::instrument(skip_all, err)]
347    async fn connect_with_retry(
348        &mut self,
349        from_stream_tx: &mut Sender<T::Output>,
350        client: &mut Arc<BetfairRpcClient<Authenticated>>,
351    ) -> eyre::Result<Framed<tokio_rustls::client::TlsStream<TcpStream>, StreamAPIClientCodec>>
352    {
353        let mut backoff = ExponentialBuilder::new().build();
354        let mut delay = async || {
355            if let Some(delay) = backoff.next() {
356                sleep(delay).await;
357                Ok(())
358            } else {
359                eyre::bail!("exceeded retry attempts, could not connect");
360            }
361        };
362
363        loop {
364            let server_addr = self.client.stream.url();
365            let host = server_addr
366                .host_str()
367                .ok_or_else(|| eyre::eyre!("invalid betfair url"))?;
368            let port = server_addr.port().unwrap_or(443);
369
370            let domain_str = server_addr
371                .domain()
372                .ok_or_else(|| eyre::eyre!("domain must be known"))?;
373            let domain = rustls::pki_types::ServerName::try_from(domain_str.to_owned())
374                .wrap_err("failed to parse server name")?;
375
376            // Resolve socket addresses each iteration in case DNS changes
377            let Some(socket_addr) = tokio::net::lookup_host((host, port)).await?.next() else {
378                eyre::bail!("no valid socket addresses for {host}:{port}")
379            };
380
381            let tcp_stream = TcpStream::connect(socket_addr).await;
382            let Ok(stream) = tcp_stream else {
383                tracing::error!(err = ?tcp_stream.unwrap_err(), "Connect error. Retrying...");
384                delay().await?;
385                continue;
386            };
387            let tls_stream = tls_connector()?.connect(domain.clone(), stream).await?;
388            let mut tls_stream = Framed::new(tls_stream, StreamAPIClientCodec);
389
390            match self
391                .handshake(from_stream_tx, client, &mut tls_stream)
392                .await
393            {
394                Ok(()) => return Ok(tls_stream),
395                Err(err) => match err {
396                    HandshakeErr::WaitAndRetry => {
397                        delay().await?;
398                        continue;
399                    }
400                    HandshakeErr::Reauthenticate => {
401                        let (new_client, _) = self.client.clone().authenticate().await?;
402                        *client = new_client;
403                        delay().await?;
404                        continue;
405                    }
406                    HandshakeErr::Fatal => eyre::bail!("fatal error in stream processing"),
407                },
408            }
409        }
410    }
411
412    #[tracing::instrument(err, skip_all)]
413    async fn handshake(
414        &mut self,
415        from_stream_tx: &mut Sender<T::Output>,
416        client: &BetfairRpcClient<Authenticated>,
417        stream: &mut Framed<tokio_rustls::client::TlsStream<TcpStream>, StreamAPIClientCodec>,
418    ) -> Result<(), HandshakeErr> {
419        // await con message
420        let res = stream
421            .next()
422            .await
423            .transpose()
424            .inspect_err(|err| {
425                tracing::warn!(?err, "error when parsing stream message");
426            })
427            .map_err(|_| HandshakeErr::WaitAndRetry)?
428            .ok_or(HandshakeErr::WaitAndRetry)?;
429        tracing::info!(?res, "message from stream");
430        let message = self
431            .processor
432            .process_message(res.clone())
433            .ok_or(HandshakeErr::Fatal)
434            .inspect_err(|err| tracing::error!(?err))?;
435        from_stream_tx
436            .send(message.clone())
437            .await
438            .inspect_err(|err| tracing::warn!(?err))
439            .map_err(|_| HandshakeErr::Fatal)?;
440        let ResponseMessage::Connection(_) = &res else {
441            tracing::warn!("stream responded with invalid connection message");
442            return Err(HandshakeErr::Reauthenticate);
443        };
444
445        // send auth msg
446        let msg = authentication_message::AuthenticationMessage {
447            id: Some(-1),
448            session: client.session_token().0.expose_secret().clone(),
449            app_key: self
450                .client
451                .secret_provider
452                .application_key
453                .0
454                .expose_secret()
455                .clone(),
456        };
457        stream
458            .send(RequestMessage::Authentication(msg))
459            .await
460            .inspect_err(|err| tracing::warn!(?err, "stream exited"))
461            .map_err(|_| HandshakeErr::WaitAndRetry)?;
462
463        // await status message
464        let message = stream
465            .next()
466            .await
467            .transpose()
468            .inspect_err(|err| {
469                tracing::warn!(?err, "error when parsing stream message");
470            })
471            .map_err(|_| HandshakeErr::WaitAndRetry)?
472            .ok_or(HandshakeErr::WaitAndRetry)?;
473        let processed_message = self
474            .processor
475            .process_message(message.clone())
476            .ok_or(HandshakeErr::Fatal)
477            .inspect_err(|err| tracing::warn!(?err))
478            .map_err(|_| HandshakeErr::Fatal)?;
479        from_stream_tx
480            .send(processed_message)
481            .await
482            .inspect_err(|err| tracing::warn!(?err))
483            .map_err(|_| HandshakeErr::Fatal)?;
484        tracing::info!(?message, "message from stream");
485        let ResponseMessage::Status(status_message) = &message else {
486            tracing::warn!("expected status message, got {message:?}");
487            return Err(HandshakeErr::WaitAndRetry);
488        };
489
490        let StatusMessage::Failure(err) = &status_message else {
491            return Ok(());
492        };
493
494        tracing::error!(?err, "stream respondend wit an error");
495        let action = match err.error_code {
496            ErrorCode::NoAppKey => HandshakeErr::Fatal,
497            ErrorCode::InvalidAppKey => HandshakeErr::Fatal,
498            ErrorCode::NoSession => HandshakeErr::Reauthenticate,
499            ErrorCode::InvalidSessionInformation => HandshakeErr::Reauthenticate,
500            ErrorCode::NotAuthorized => HandshakeErr::Reauthenticate,
501            ErrorCode::InvalidInput => HandshakeErr::Fatal,
502            ErrorCode::InvalidClock => HandshakeErr::Fatal,
503            ErrorCode::UnexpectedError => HandshakeErr::Fatal,
504            ErrorCode::Timeout => HandshakeErr::WaitAndRetry,
505            ErrorCode::SubscriptionLimitExceeded => HandshakeErr::WaitAndRetry,
506            ErrorCode::InvalidRequest => HandshakeErr::Fatal,
507            ErrorCode::ConnectionFailed => HandshakeErr::WaitAndRetry,
508            ErrorCode::MaxConnectionLimitExceeded => HandshakeErr::Fatal,
509            ErrorCode::TooManyRequests => HandshakeErr::WaitAndRetry,
510        };
511
512        Err(action)
513    }
514}
515
516#[derive(Debug)]
517enum HandshakeErr {
518    WaitAndRetry,
519    Reauthenticate,
520    Fatal,
521}
522
523impl fmt::Display for HandshakeErr {
524    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
525        write!(f, "Stream Handshake Error {:?}", self)
526    }
527}
528
529impl core::error::Error for HandshakeErr {}
530
531#[tracing::instrument(err)]
532fn tls_connector() -> eyre::Result<tokio_rustls::TlsConnector> {
533    use tokio_rustls::TlsConnector;
534
535    let mut roots = rustls::RootCertStore::empty();
536    let native_certs = rustls_native_certs::load_native_certs();
537    for cert in native_certs.certs {
538        roots.add(cert)?;
539    }
540
541    let config = rustls::ClientConfig::builder()
542        .with_root_certificates(roots)
543        .with_no_client_auth();
544    Ok(TlsConnector::from(Arc::new(config)))
545}
546
547/// Defines the encoding and decoding of Betfair stream api data structures using tokio
548pub struct StreamAPIClientCodec;
549
550impl Decoder for StreamAPIClientCodec {
551    type Item = ResponseMessage;
552    type Error = eyre::Report;
553
554    fn decode(&mut self, src: &mut bytes::BytesMut) -> Result<Option<Self::Item>, Self::Error> {
555        // Find position of `\n` first
556        if let Some(pos) = src.iter().position(|&byte| byte == b'\n') {
557            // Check if the preceding byte is `\r`
558            let delimiter_size = if pos > 0 && src[pos - 1] == b'\r' {
559                2
560            } else {
561                1
562            };
563
564            // Extract up to and including the delimiter
565            let line = src.split_to(pos + 1);
566
567            // Separate out the delimiter bytes
568            let (json_part, _) = line.split_at(line.len().saturating_sub(delimiter_size));
569
570            // Now we can parse it as JSON
571            let data = serde_json::from_slice::<Self::Item>(json_part)?;
572            return Ok(Some(data));
573        }
574        Ok(None)
575    }
576}
577
578impl Encoder<RequestMessage> for StreamAPIClientCodec {
579    type Error = eyre::Report;
580
581    fn encode(
582        &mut self,
583        item: RequestMessage,
584        dst: &mut bytes::BytesMut,
585    ) -> Result<(), Self::Error> {
586        // Serialize the item to a JSON string
587        let json = serde_json::to_string(&item)?;
588        // Write the JSON string to the buffer, followed by a newline
589        dst.extend_from_slice(json.as_bytes());
590        dst.extend_from_slice(b"\r\n");
591        Ok(())
592    }
593}
594
595#[cfg(test)]
596mod tests {
597
598    use core::fmt::Write as _;
599
600    use super::*;
601
602    #[tokio::test]
603    async fn can_resolve_host_ipv4() {
604        let url = url::Url::parse("tcptls://stream-api.betfair.com:443").unwrap();
605        let host = url.host_str().unwrap();
606        let port = url
607            .port()
608            .unwrap_or_else(|| if url.scheme() == "https" { 443 } else { 80 });
609        let socket_addr = tokio::net::lookup_host((host, port))
610            .await
611            .unwrap()
612            .next()
613            .unwrap();
614        assert!(socket_addr.ip().is_ipv4());
615        assert_eq!(socket_addr.port(), 443);
616    }
617
618    #[test]
619    fn can_decode_single_message() {
620        let msg = r#"{"op":"connection","connectionId":"002-051134157842-432409"}"#;
621        let separator = "\r\n";
622        let data = format!("{msg}{separator}");
623
624        let mut codec = StreamAPIClientCodec;
625        let mut buf = bytes::BytesMut::from(data.as_bytes());
626        let msg = codec.decode(&mut buf).unwrap().unwrap();
627
628        assert!(matches!(msg, ResponseMessage::Connection(_)));
629    }
630
631    #[test]
632    fn can_decode_multiple_messages() {
633        // contains two messages
634        let msg_one = r#"{"op":"connection","connectionId":"002-051134157842-432409"}"#;
635        let msg_two = r#"{"op":"ocm","id":3,"clk":"AAAAAAAA","status":503,"pt":1498137379766,"ct":"HEARTBEAT"}"#;
636        let separator = "\r\n";
637        let data = format!("{msg_one}{separator}{msg_two}{separator}");
638
639        let mut codec = StreamAPIClientCodec;
640        let mut buf = bytes::BytesMut::from(data.as_bytes());
641        let msg_one = codec.decode(&mut buf).unwrap().unwrap();
642        let msg_two = codec.decode(&mut buf).unwrap().unwrap();
643
644        assert!(matches!(msg_one, ResponseMessage::Connection(_)));
645        assert!(matches!(msg_two, ResponseMessage::OrderChange(_)));
646    }
647
648    #[test]
649    fn can_decode_multiple_partial_messages() {
650        // contains two messages
651        let msg_one = r#"{"op":"connection","connectionId":"002-051134157842-432409"}"#;
652        let msg_two_pt_one = r#"{"op":"ocm","id":3,"clk""#;
653        let msg_two_pt_two = r#":"AAAAAAAA","status":503,"pt":1498137379766,"ct":"HEARTBEAT"}"#;
654        let separator = "\r\n";
655        let data = format!("{msg_one}{separator}{msg_two_pt_one}");
656
657        let mut codec = StreamAPIClientCodec;
658        let mut buf = bytes::BytesMut::from(data.as_bytes());
659        let msg_one = codec.decode(&mut buf).unwrap().unwrap();
660        let msg_two_attempt = codec.decode(&mut buf).unwrap();
661        assert!(msg_two_attempt.is_none());
662        buf.write_str(msg_two_pt_two).unwrap();
663        buf.write_str(separator).unwrap();
664        let msg_two = codec.decode(&mut buf).unwrap().unwrap();
665
666        assert!(matches!(msg_one, ResponseMessage::Connection(_)));
667        assert!(matches!(msg_two, ResponseMessage::OrderChange(_)));
668    }
669
670    #[test]
671    fn can_decode_subsequent_messages() {
672        // contains two messages
673        let msg_one = r#"{"op":"connection","connectionId":"002-051134157842-432409"}"#;
674        let msg_two = r#"{"op":"ocm","id":3,"clk":"AAAAAAAA","status":503,"pt":1498137379766,"ct":"HEARTBEAT"}"#;
675        let separator = "\r\n";
676        let data = format!("{msg_one}{separator}");
677
678        let mut codec = StreamAPIClientCodec;
679        let mut buf = bytes::BytesMut::from(data.as_bytes());
680        let msg_one = codec.decode(&mut buf).unwrap().unwrap();
681        let msg_two_attempt = codec.decode(&mut buf).unwrap();
682        assert!(msg_two_attempt.is_none());
683        let data = format!("{msg_two}{separator}");
684        buf.write_str(data.as_str()).unwrap();
685        let msg_two = codec.decode(&mut buf).unwrap().unwrap();
686
687        assert!(matches!(msg_one, ResponseMessage::Connection(_)));
688        assert!(matches!(msg_two, ResponseMessage::OrderChange(_)));
689    }
690
691    #[test]
692    fn can_encode_message() {
693        let msg = RequestMessage::Authentication(
694            betfair_stream_types::request::authentication_message::AuthenticationMessage {
695                id: Some(1),
696                session: "sss".to_owned(),
697                app_key: "aaaa".to_owned(),
698            },
699        );
700        let mut codec = StreamAPIClientCodec;
701        let mut buf = bytes::BytesMut::new();
702        codec.encode(msg, &mut buf).unwrap();
703
704        let data = buf.freeze();
705        let data = core::str::from_utf8(&data).unwrap();
706
707        // assert that we have the suffix \r\n
708        assert!(data.ends_with("\r\n"));
709        // assert that we have the prefix {"op":"authentication"
710        assert!(data.starts_with("{\"op\":\"authentication\""));
711    }
712}
betfair_stream_api/lib.rs

betfair_stream_api/
lib.rs
