foundry_common/provider/
runtime_transport.rs

1//! Runtime transport that connects on first request, which can take either of an HTTP,
2//! WebSocket, or IPC transport. Retries are handled by a client layer (e.g.,
3//! `RetryBackoffLayer`) when used.
4
5use crate::{DEFAULT_USER_AGENT, REQUEST_TIMEOUT};
6use alloy_json_rpc::{RequestPacket, ResponsePacket};
7use alloy_pubsub::{PubSubConnect, PubSubFrontend};
8use alloy_rpc_types::engine::{Claims, JwtSecret};
9use alloy_transport::{
10    Authorization, BoxTransport, TransportError, TransportErrorKind, TransportFut,
11};
12use alloy_transport_http::Http;
13use alloy_transport_ipc::IpcConnect;
14use alloy_transport_ws::WsConnect;
15use reqwest::header::{HeaderName, HeaderValue};
16use std::{fmt, path::PathBuf, str::FromStr, sync::Arc};
17use thiserror::Error;
18use tokio::sync::RwLock;
19use tower::Service;
20use url::Url;
21
22/// An enum representing the different transports that can be used to connect to a runtime.
23/// Only meant to be used internally by [RuntimeTransport].
24#[derive(Clone, Debug)]
25pub enum InnerTransport {
26    /// HTTP transport
27    Http(Http<reqwest::Client>),
28    /// WebSocket transport
29    Ws(PubSubFrontend),
30    /// IPC transport
31    Ipc(PubSubFrontend),
32}
33
34/// Error type for the runtime transport.
35#[derive(Error, Debug)]
36pub enum RuntimeTransportError {
37    /// Internal transport error
38    #[error("Internal transport error: {0} with {1}")]
39    TransportError(TransportError, String),
40
41    /// Invalid URL scheme
42    #[error("URL scheme is not supported: {0}")]
43    BadScheme(String),
44
45    /// Invalid HTTP header
46    #[error("Invalid HTTP header: {0}")]
47    BadHeader(String),
48
49    /// Invalid file path
50    #[error("Invalid IPC file path: {0}")]
51    BadPath(String),
52
53    /// Invalid construction of Http provider
54    #[error(transparent)]
55    HttpConstructionError(#[from] reqwest::Error),
56
57    /// Invalid JWT
58    #[error("Invalid JWT: {0}")]
59    InvalidJwt(String),
60}
61
62/// Runtime transport that only connects on first request.
63///
64/// A runtime transport is a custom [`alloy_transport::Transport`] that only connects when the
65/// *first* request is made. When the first request is made, it will connect to the runtime using
66/// either an HTTP WebSocket, or IPC transport depending on the URL used.
67/// Retries for rate-limiting and timeout-related errors are handled by an external
68/// client layer (e.g., `RetryBackoffLayer`) when configured.
69#[derive(Clone, Debug)]
70pub struct RuntimeTransport {
71    /// The inner actual transport used.
72    inner: Arc<RwLock<Option<InnerTransport>>>,
73    /// The URL to connect to.
74    url: Url,
75    /// The headers to use for requests.
76    headers: Vec<String>,
77    /// The JWT to use for requests.
78    jwt: Option<String>,
79    /// The timeout for requests.
80    timeout: std::time::Duration,
81    /// Whether to accept invalid certificates.
82    accept_invalid_certs: bool,
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    accept_invalid_certs: bool,
93}
94
95impl RuntimeTransportBuilder {
96    /// Create a new builder with the given URL.
97    pub fn new(url: Url) -> Self {
98        Self {
99            url,
100            headers: vec![],
101            jwt: None,
102            timeout: REQUEST_TIMEOUT,
103            accept_invalid_certs: false,
104        }
105    }
106
107    /// Set the URL for the transport.
108    pub fn with_headers(mut self, headers: Vec<String>) -> Self {
109        self.headers = headers;
110        self
111    }
112
113    /// Set the JWT for the transport.
114    pub fn with_jwt(mut self, jwt: Option<String>) -> Self {
115        self.jwt = jwt;
116        self
117    }
118
119    /// Set the timeout for the transport.
120    pub fn with_timeout(mut self, timeout: std::time::Duration) -> Self {
121        self.timeout = timeout;
122        self
123    }
124
125    /// Set whether to accept invalid certificates.
126    pub fn accept_invalid_certs(mut self, accept_invalid_certs: bool) -> Self {
127        self.accept_invalid_certs = accept_invalid_certs;
128        self
129    }
130
131    /// Builds the [RuntimeTransport] and returns it in a disconnected state.
132    /// The runtime transport will then connect when the first request happens.
133    pub fn build(self) -> RuntimeTransport {
134        RuntimeTransport {
135            inner: Arc::new(RwLock::new(None)),
136            url: self.url,
137            headers: self.headers,
138            jwt: self.jwt,
139            timeout: self.timeout,
140            accept_invalid_certs: self.accept_invalid_certs,
141        }
142    }
143}
144
145impl fmt::Display for RuntimeTransport {
146    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
147        write!(f, "RuntimeTransport {}", self.url)
148    }
149}
150
151impl RuntimeTransport {
152    /// Connects the underlying transport, depending on the URL scheme.
153    pub async fn connect(&self) -> Result<InnerTransport, RuntimeTransportError> {
154        match self.url.scheme() {
155            "http" | "https" => self.connect_http(),
156            "ws" | "wss" => self.connect_ws().await,
157            "file" => self.connect_ipc().await,
158            _ => Err(RuntimeTransportError::BadScheme(self.url.scheme().to_string())),
159        }
160    }
161
162    /// Creates a new reqwest client from this transport.
163    pub fn reqwest_client(&self) -> Result<reqwest::Client, RuntimeTransportError> {
164        let mut client_builder = reqwest::Client::builder()
165            .timeout(self.timeout)
166            .tls_built_in_root_certs(self.url.scheme() == "https")
167            .danger_accept_invalid_certs(self.accept_invalid_certs);
168        let mut headers = reqwest::header::HeaderMap::new();
169
170        // If there's a JWT, add it to the headers if we can decode it.
171        if let Some(jwt) = self.jwt.clone() {
172            let auth =
173                build_auth(jwt).map_err(|e| RuntimeTransportError::InvalidJwt(e.to_string()))?;
174
175            let mut auth_value: HeaderValue =
176                HeaderValue::from_str(&auth.to_string()).expect("Header should be valid string");
177            auth_value.set_sensitive(true);
178
179            headers.insert(reqwest::header::AUTHORIZATION, auth_value);
180        };
181
182        // Add any custom headers.
183        for header in &self.headers {
184            let make_err = || RuntimeTransportError::BadHeader(header.to_string());
185
186            let (key, val) = header.split_once(':').ok_or_else(make_err)?;
187
188            headers.insert(
189                HeaderName::from_str(key.trim()).map_err(|_| make_err())?,
190                HeaderValue::from_str(val.trim()).map_err(|_| make_err())?,
191            );
192        }
193
194        if !headers.contains_key(reqwest::header::USER_AGENT) {
195            headers.insert(
196                reqwest::header::USER_AGENT,
197                HeaderValue::from_str(DEFAULT_USER_AGENT)
198                    .expect("User-Agent should be valid string"),
199            );
200        }
201
202        client_builder = client_builder.default_headers(headers);
203
204        Ok(client_builder.build()?)
205    }
206
207    /// Connects to an HTTP [alloy_transport_http::Http] transport.
208    fn connect_http(&self) -> Result<InnerTransport, RuntimeTransportError> {
209        let client = self.reqwest_client()?;
210        Ok(InnerTransport::Http(Http::with_client(client, self.url.clone())))
211    }
212
213    /// Connects to a WS transport.
214    async fn connect_ws(&self) -> Result<InnerTransport, RuntimeTransportError> {
215        let auth = self.jwt.as_ref().and_then(|jwt| build_auth(jwt.clone()).ok());
216        let mut ws = WsConnect::new(self.url.to_string());
217        if let Some(auth) = auth {
218            ws = ws.with_auth(auth);
219        };
220        let service = ws
221            .into_service()
222            .await
223            .map_err(|e| RuntimeTransportError::TransportError(e, self.url.to_string()))?;
224        Ok(InnerTransport::Ws(service))
225    }
226
227    /// Connects to an IPC transport.
228    async fn connect_ipc(&self) -> Result<InnerTransport, RuntimeTransportError> {
229        let path = url_to_file_path(&self.url)
230            .map_err(|_| RuntimeTransportError::BadPath(self.url.to_string()))?;
231        let ipc_connector = IpcConnect::new(path.clone());
232        let ipc = ipc_connector.into_service().await.map_err(|e| {
233            RuntimeTransportError::TransportError(e, path.clone().display().to_string())
234        })?;
235        Ok(InnerTransport::Ipc(ipc))
236    }
237
238    /// Sends a request using the underlying transport.
239    /// If this is the first request, it will connect to the appropriate transport depending on the
240    /// URL scheme. Retries are performed by an external client layer (e.g., `RetryBackoffLayer`),
241    /// if such a layer is configured by the caller.
242    /// For sending the actual request, this action is delegated down to the
243    /// underlying transport through Tower's [tower::Service::call]. See tower's [tower::Service]
244    /// trait for more information.
245    pub fn request(&self, req: RequestPacket) -> TransportFut<'static> {
246        let this = self.clone();
247        Box::pin(async move {
248            let mut inner = this.inner.read().await;
249            if inner.is_none() {
250                drop(inner);
251                {
252                    let mut inner_mut = this.inner.write().await;
253                    if inner_mut.is_none() {
254                        *inner_mut =
255                            Some(this.connect().await.map_err(TransportErrorKind::custom)?);
256                    }
257                }
258                inner = this.inner.read().await;
259            }
260
261            // SAFETY: We just checked that the inner transport exists.
262            match inner.clone().expect("must've been initialized") {
263                InnerTransport::Http(mut http) => http.call(req),
264                InnerTransport::Ws(mut ws) => ws.call(req),
265                InnerTransport::Ipc(mut ipc) => ipc.call(req),
266            }
267            .await
268        })
269    }
270
271    /// Convert this transport into a boxed trait object.
272    pub fn boxed(self) -> BoxTransport
273    where
274        Self: Sized + Clone + Send + Sync + 'static,
275    {
276        BoxTransport::new(self)
277    }
278}
279
280impl tower::Service<RequestPacket> for RuntimeTransport {
281    type Response = ResponsePacket;
282    type Error = TransportError;
283    type Future = TransportFut<'static>;
284
285    #[inline]
286    fn poll_ready(
287        &mut self,
288        _cx: &mut std::task::Context<'_>,
289    ) -> std::task::Poll<Result<(), Self::Error>> {
290        std::task::Poll::Ready(Ok(()))
291    }
292
293    #[inline]
294    fn call(&mut self, req: RequestPacket) -> Self::Future {
295        self.request(req)
296    }
297}
298
299impl tower::Service<RequestPacket> for &RuntimeTransport {
300    type Response = ResponsePacket;
301    type Error = TransportError;
302    type Future = TransportFut<'static>;
303
304    #[inline]
305    fn poll_ready(
306        &mut self,
307        _cx: &mut std::task::Context<'_>,
308    ) -> std::task::Poll<Result<(), Self::Error>> {
309        std::task::Poll::Ready(Ok(()))
310    }
311
312    #[inline]
313    fn call(&mut self, req: RequestPacket) -> Self::Future {
314        self.request(req)
315    }
316}
317
318fn build_auth(jwt: String) -> eyre::Result<Authorization> {
319    // Decode jwt from hex, then generate claims (iat with current timestamp)
320    let secret = JwtSecret::from_hex(jwt)?;
321    let claims = Claims::default();
322    let token = secret.encode(&claims)?;
323
324    let auth = Authorization::Bearer(token);
325
326    Ok(auth)
327}
328
329#[cfg(windows)]
330fn url_to_file_path(url: &Url) -> Result<PathBuf, ()> {
331    const PREFIX: &str = "file:///pipe/";
332
333    let url_str = url.as_str();
334
335    if let Some(pipe_name) = url_str.strip_prefix(PREFIX) {
336        let pipe_path = format!(r"\\.\pipe\{pipe_name}");
337        return Ok(PathBuf::from(pipe_path));
338    }
339
340    url.to_file_path()
341}
342
343#[cfg(not(windows))]
344fn url_to_file_path(url: &Url) -> Result<PathBuf, ()> {
345    url.to_file_path()
346}
347
348#[cfg(test)]
349mod tests {
350    use super::*;
351    use reqwest::header::HeaderMap;
352
353    #[tokio::test]
354    async fn test_user_agent_header() {
355        let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
356        let url = Url::parse(&format!("http://{}", listener.local_addr().unwrap())).unwrap();
357
358        let http_handler = axum::routing::get(|actual_headers: HeaderMap| {
359            let user_agent = HeaderName::from_str("User-Agent").unwrap();
360            assert_eq!(actual_headers[user_agent], HeaderValue::from_str("test-agent").unwrap());
361
362            async { "" }
363        });
364
365        let server_task = tokio::spawn(async move {
366            axum::serve(listener, http_handler.into_make_service()).await.unwrap()
367        });
368
369        let transport = RuntimeTransportBuilder::new(url.clone())
370            .with_headers(vec!["User-Agent: test-agent".to_string()])
371            .build();
372        let inner = transport.connect_http().unwrap();
373
374        match inner {
375            InnerTransport::Http(http) => {
376                let _ = http.client().get(url).send().await.unwrap();
377
378                // assert inside http_handler
379            }
380            _ => unreachable!(),
381        }
382
383        server_task.abort();
384    }
385}
foundry_common/provider/runtime_transport.rs

foundry_common/provider/
runtime_transport.rs
