foundry_common/provider/
runtime_transport.rs

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1//! Runtime transport that connects on first request, which can take either of an HTTP,
2//! WebSocket, or IPC transport and supports retries based on CUPS logic.
3
4use crate::{DEFAULT_USER_AGENT, REQUEST_TIMEOUT};
5use alloy_json_rpc::{RequestPacket, ResponsePacket};
6use alloy_pubsub::{PubSubConnect, PubSubFrontend};
7use alloy_rpc_types::engine::{Claims, JwtSecret};
8use alloy_transport::{
9    Authorization, BoxTransport, TransportError, TransportErrorKind, TransportFut,
10};
11use alloy_transport_http::Http;
12use alloy_transport_ipc::IpcConnect;
13use alloy_transport_ws::WsConnect;
14use reqwest::header::{HeaderName, HeaderValue};
15use std::{fmt, path::PathBuf, str::FromStr, sync::Arc};
16use thiserror::Error;
17use tokio::sync::RwLock;
18use tower::Service;
19use url::Url;
20
21/// An enum representing the different transports that can be used to connect to a runtime.
22/// Only meant to be used internally by [RuntimeTransport].
23#[derive(Clone, Debug)]
24pub enum InnerTransport {
25    /// HTTP transport
26    Http(Http<reqwest::Client>),
27    /// WebSocket transport
28    Ws(PubSubFrontend),
29    /// IPC transport
30    Ipc(PubSubFrontend),
31}
32
33/// Error type for the runtime transport.
34#[derive(Error, Debug)]
35pub enum RuntimeTransportError {
36    /// Internal transport error
37    #[error("Internal transport error: {0} with {1}")]
38    TransportError(TransportError, String),
39
40    /// Failed to lock the transport
41    #[error("Failed to lock the transport")]
42    LockError,
43
44    /// Invalid URL scheme
45    #[error("URL scheme is not supported: {0}")]
46    BadScheme(String),
47
48    /// Invalid HTTP header
49    #[error("Invalid HTTP header: {0}")]
50    BadHeader(String),
51
52    /// Invalid file path
53    #[error("Invalid IPC file path: {0}")]
54    BadPath(String),
55
56    /// Invalid construction of Http provider
57    #[error(transparent)]
58    HttpConstructionError(#[from] reqwest::Error),
59
60    /// Invalid JWT
61    #[error("Invalid JWT: {0}")]
62    InvalidJwt(String),
63}
64
65/// Runtime transport that only connects on first request.
66///
67/// A runtime transport is a custom [`alloy_transport::Transport`] that only connects when the
68/// *first* request is made. When the first request is made, it will connect to the runtime using
69/// either an HTTP WebSocket, or IPC transport depending on the URL used.
70/// It also supports retries for rate-limiting and timeout-related errors.
71#[derive(Clone, Debug, Error)]
72pub struct RuntimeTransport {
73    /// The inner actual transport used.
74    inner: Arc<RwLock<Option<InnerTransport>>>,
75    /// The URL to connect to.
76    url: Url,
77    /// The headers to use for requests.
78    headers: Vec<String>,
79    /// The JWT to use for requests.
80    jwt: Option<String>,
81    /// The timeout for requests.
82    timeout: std::time::Duration,
83}
84
85/// A builder for [RuntimeTransport].
86#[derive(Debug)]
87pub struct RuntimeTransportBuilder {
88    url: Url,
89    headers: Vec<String>,
90    jwt: Option<String>,
91    timeout: std::time::Duration,
92}
93
94impl RuntimeTransportBuilder {
95    /// Create a new builder with the given URL.
96    pub fn new(url: Url) -> Self {
97        Self { url, headers: vec![], jwt: None, timeout: REQUEST_TIMEOUT }
98    }
99
100    /// Set the URL for the transport.
101    pub fn with_headers(mut self, headers: Vec<String>) -> Self {
102        self.headers = headers;
103        self
104    }
105
106    /// Set the JWT for the transport.
107    pub fn with_jwt(mut self, jwt: Option<String>) -> Self {
108        self.jwt = jwt;
109        self
110    }
111
112    /// Set the timeout for the transport.
113    pub fn with_timeout(mut self, timeout: std::time::Duration) -> Self {
114        self.timeout = timeout;
115        self
116    }
117
118    /// Builds the [RuntimeTransport] and returns it in a disconnected state.
119    /// The runtime transport will then connect when the first request happens.
120    pub fn build(self) -> RuntimeTransport {
121        RuntimeTransport {
122            inner: Arc::new(RwLock::new(None)),
123            url: self.url,
124            headers: self.headers,
125            jwt: self.jwt,
126            timeout: self.timeout,
127        }
128    }
129}
130
131impl fmt::Display for RuntimeTransport {
132    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
133        write!(f, "RuntimeTransport {}", self.url)
134    }
135}
136
137impl RuntimeTransport {
138    /// Connects the underlying transport, depending on the URL scheme.
139    pub async fn connect(&self) -> Result<InnerTransport, RuntimeTransportError> {
140        match self.url.scheme() {
141            "http" | "https" => self.connect_http(),
142            "ws" | "wss" => self.connect_ws().await,
143            "file" => self.connect_ipc().await,
144            _ => Err(RuntimeTransportError::BadScheme(self.url.scheme().to_string())),
145        }
146    }
147
148    /// Creates a new reqwest client from this transport.
149    pub fn reqwest_client(&self) -> Result<reqwest::Client, RuntimeTransportError> {
150        let mut client_builder = reqwest::Client::builder()
151            .timeout(self.timeout)
152            .tls_built_in_root_certs(self.url.scheme() == "https");
153        let mut headers = reqwest::header::HeaderMap::new();
154
155        // If there's a JWT, add it to the headers if we can decode it.
156        if let Some(jwt) = self.jwt.clone() {
157            let auth =
158                build_auth(jwt).map_err(|e| RuntimeTransportError::InvalidJwt(e.to_string()))?;
159
160            let mut auth_value: HeaderValue =
161                HeaderValue::from_str(&auth.to_string()).expect("Header should be valid string");
162            auth_value.set_sensitive(true);
163
164            headers.insert(reqwest::header::AUTHORIZATION, auth_value);
165        };
166
167        // Add any custom headers.
168        for header in &self.headers {
169            let make_err = || RuntimeTransportError::BadHeader(header.to_string());
170
171            let (key, val) = header.split_once(':').ok_or_else(make_err)?;
172
173            headers.insert(
174                HeaderName::from_str(key.trim()).map_err(|_| make_err())?,
175                HeaderValue::from_str(val.trim()).map_err(|_| make_err())?,
176            );
177        }
178
179        if !headers.contains_key(reqwest::header::USER_AGENT) {
180            headers.insert(
181                reqwest::header::USER_AGENT,
182                HeaderValue::from_str(DEFAULT_USER_AGENT)
183                    .expect("User-Agent should be valid string"),
184            );
185        }
186
187        client_builder = client_builder.default_headers(headers);
188
189        Ok(client_builder.build()?)
190    }
191
192    /// Connects to an HTTP [alloy_transport_http::Http] transport.
193    fn connect_http(&self) -> Result<InnerTransport, RuntimeTransportError> {
194        let client = self.reqwest_client()?;
195        Ok(InnerTransport::Http(Http::with_client(client, self.url.clone())))
196    }
197
198    /// Connects to a WS transport.
199    async fn connect_ws(&self) -> Result<InnerTransport, RuntimeTransportError> {
200        let auth = self.jwt.as_ref().and_then(|jwt| build_auth(jwt.clone()).ok());
201        let mut ws = WsConnect::new(self.url.to_string());
202        if let Some(auth) = auth {
203            ws = ws.with_auth(auth);
204        };
205        let service = ws
206            .into_service()
207            .await
208            .map_err(|e| RuntimeTransportError::TransportError(e, self.url.to_string()))?;
209        Ok(InnerTransport::Ws(service))
210    }
211
212    /// Connects to an IPC transport.
213    async fn connect_ipc(&self) -> Result<InnerTransport, RuntimeTransportError> {
214        let path = url_to_file_path(&self.url)
215            .map_err(|_| RuntimeTransportError::BadPath(self.url.to_string()))?;
216        let ipc_connector = IpcConnect::new(path.clone());
217        let ipc = ipc_connector.into_service().await.map_err(|e| {
218            RuntimeTransportError::TransportError(e, path.clone().display().to_string())
219        })?;
220        Ok(InnerTransport::Ipc(ipc))
221    }
222
223    /// Sends a request using the underlying transport.
224    /// If this is the first request, it will connect to the appropriate transport depending on the
225    /// URL scheme. When sending the request, retries will be automatically handled depending
226    /// on the parameters set on the [RuntimeTransport].
227    /// For sending the actual request, this action is delegated down to the
228    /// underlying transport through Tower's [tower::Service::call]. See tower's [tower::Service]
229    /// trait for more information.
230    pub fn request(&self, req: RequestPacket) -> TransportFut<'static> {
231        let this = self.clone();
232        Box::pin(async move {
233            let mut inner = this.inner.read().await;
234            if inner.is_none() {
235                drop(inner);
236                {
237                    let mut inner_mut = this.inner.write().await;
238                    if inner_mut.is_none() {
239                        *inner_mut =
240                            Some(this.connect().await.map_err(TransportErrorKind::custom)?);
241                    }
242                }
243                inner = this.inner.read().await;
244            }
245
246            // SAFETY: We just checked that the inner transport exists.
247            match inner.clone().expect("must've been initialized") {
248                InnerTransport::Http(mut http) => http.call(req),
249                InnerTransport::Ws(mut ws) => ws.call(req),
250                InnerTransport::Ipc(mut ipc) => ipc.call(req),
251            }
252            .await
253        })
254    }
255
256    /// Convert this transport into a boxed trait object.
257    pub fn boxed(self) -> BoxTransport
258    where
259        Self: Sized + Clone + Send + Sync + 'static,
260    {
261        BoxTransport::new(self)
262    }
263}
264
265impl tower::Service<RequestPacket> for RuntimeTransport {
266    type Response = ResponsePacket;
267    type Error = TransportError;
268    type Future = TransportFut<'static>;
269
270    #[inline]
271    fn poll_ready(
272        &mut self,
273        _cx: &mut std::task::Context<'_>,
274    ) -> std::task::Poll<Result<(), Self::Error>> {
275        std::task::Poll::Ready(Ok(()))
276    }
277
278    #[inline]
279    fn call(&mut self, req: RequestPacket) -> Self::Future {
280        self.request(req)
281    }
282}
283
284impl tower::Service<RequestPacket> for &RuntimeTransport {
285    type Response = ResponsePacket;
286    type Error = TransportError;
287    type Future = TransportFut<'static>;
288
289    #[inline]
290    fn poll_ready(
291        &mut self,
292        _cx: &mut std::task::Context<'_>,
293    ) -> std::task::Poll<Result<(), Self::Error>> {
294        std::task::Poll::Ready(Ok(()))
295    }
296
297    #[inline]
298    fn call(&mut self, req: RequestPacket) -> Self::Future {
299        self.request(req)
300    }
301}
302
303fn build_auth(jwt: String) -> eyre::Result<Authorization> {
304    // Decode jwt from hex, then generate claims (iat with current timestamp)
305    let secret = JwtSecret::from_hex(jwt)?;
306    let claims = Claims::default();
307    let token = secret.encode(&claims)?;
308
309    let auth = Authorization::Bearer(token);
310
311    Ok(auth)
312}
313
314#[cfg(windows)]
315fn url_to_file_path(url: &Url) -> Result<PathBuf, ()> {
316    const PREFIX: &str = "file:///pipe/";
317
318    let url_str = url.as_str();
319
320    if let Some(pipe_name) = url_str.strip_prefix(PREFIX) {
321        let pipe_path = format!(r"\\.\pipe\{pipe_name}");
322        return Ok(PathBuf::from(pipe_path));
323    }
324
325    url.to_file_path()
326}
327
328#[cfg(not(windows))]
329fn url_to_file_path(url: &Url) -> Result<PathBuf, ()> {
330    url.to_file_path()
331}
332
333#[cfg(test)]
334mod tests {
335    use super::*;
336    use reqwest::header::HeaderMap;
337
338    #[tokio::test]
339    async fn test_user_agent_header() {
340        let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
341        let url = Url::parse(&format!("http://{}", listener.local_addr().unwrap())).unwrap();
342
343        let http_handler = axum::routing::get(|actual_headers: HeaderMap| {
344            let user_agent = HeaderName::from_str("User-Agent").unwrap();
345            assert_eq!(actual_headers[user_agent], HeaderValue::from_str("test-agent").unwrap());
346
347            async { "" }
348        });
349
350        let server_task = tokio::spawn(async move {
351            axum::serve(listener, http_handler.into_make_service()).await.unwrap()
352        });
353
354        let transport = RuntimeTransportBuilder::new(url.clone())
355            .with_headers(vec!["User-Agent: test-agent".to_string()])
356            .build();
357        let inner = transport.connect_http().unwrap();
358
359        match inner {
360            InnerTransport::Http(http) => {
361                let _ = http.client().get(url).send().await.unwrap();
362
363                // assert inside http_handler
364            }
365            _ => unreachable!(),
366        }
367
368        server_task.abort();
369    }
370}
foundry_common/provider/runtime_transport.rs

foundry_common/provider/
runtime_transport.rs
