OXYGENHUB

Coverage / crates/spectra-mcp/src/proxy.rs 15.5%

9 of 58 lines run, 3 of 23 functions · run #25 on main · run missed

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//! Radar from a workstation (spec §8.6): a browser cannot pin the
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//! instance's certificate, so `spectra open` serves a loopback proxy that
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//! forwards to the pinned server over TLS. It answers only loopback `Host`
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//! and `Origin`, so no other site can reach the server through it, and
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//! passes responses (the SSE stream included) through as they come.
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use crate::client::{Client, Endpoint};
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use axum::body::{Body, Bytes};
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use axum::extract::{Request, State};
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use axum::http::{header, HeaderMap, StatusCode};
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use axum::response::{IntoResponse, Response};
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use http_body_util::{BodyExt, Full};
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use std::sync::Arc;
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struct Proxy {
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    upstream: Client,
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    /// `127.0.0.1:PORT` and `localhost:PORT`.
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    hosts: Vec<String>,
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}
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/// The proxy's routes, forwarding to `upstream` as the browser at
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/// `127.0.0.1:port` asks.
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pub fn router(upstream: Endpoint, port: u16) -> axum::Router {
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    let p = Arc::new(Proxy { upstream: Client::at(upstream, None), hosts: vec![format!("127.0.0.1:{port}"), format!("localhost:{port}")] });
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    axum::Router::new().fallback(forward).with_state(p)
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}
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/// The sign-in link the server made, pointed at the proxy instead.
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pub fn local_link(url: &str, port: u16) -> String {
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    let rest = url.split_once("://").map(|(_, r)| r).unwrap_or(url);
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    let path = rest.find('/').map(|i| &rest[i..]).unwrap_or("/");
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    format!("http://127.0.0.1:{port}{path}")
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}
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fn ours(p: &Proxy, headers: &HeaderMap) -> bool {
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    let host = headers.get(header::HOST).and_then(|h| h.to_str().ok()).unwrap_or("");
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    if !p.hosts.iter().any(|h| h == host) {
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        return false;
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    }
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    match headers.get(header::ORIGIN).and_then(|o| o.to_str().ok()) {
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        None => true,
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        Some(o) => p.hosts.iter().any(|h| o == format!("http://{h}")),
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    }
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}
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async fn forward(State(p): State<Arc<Proxy>>, req: Request) -> Response {
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    if !ours(&p, req.headers()) {
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        return (StatusCode::FORBIDDEN, "this proxy serves its own page only").into_response();
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    }
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    let (parts, body) = req.into_parts();
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    let body: Bytes = match body.collect().await {
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        Ok(b) => b.to_bytes(),
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        Err(_) => return StatusCode::BAD_REQUEST.into_response(),
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    };
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    let path = parts.uri.path_and_query().map(|p| p.as_str()).unwrap_or("/");
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    let mut up = hyper::Request::builder().method(parts.method.clone()).uri(path);
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    for (k, v) in parts.headers.iter() {
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        // The proxy has checked the origin itself; hop-by-hop headers stay here.
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        if matches!(k.as_str(), "host" | "origin" | "connection" | "keep-alive" | "transfer-encoding" | "upgrade" | "referer") {
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            continue;
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        }
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        up = up.header(k, v);
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    }
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    let up = match up.header(header::HOST, "spectra").header(header::CONNECTION, "close").body(Full::new(body)) {
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        Ok(r) => r,
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        Err(_) => return StatusCode::BAD_REQUEST.into_response(),
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    };
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    match p.upstream.forward(up).await {
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        Ok(resp) => {
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            let (parts, incoming) = resp.into_parts();
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            let mut out = Response::new(Body::new(incoming));
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            *out.status_mut() = parts.status;
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            for (k, v) in parts.headers.iter() {
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                if !matches!(k.as_str(), "connection" | "transfer-encoding" | "keep-alive") {
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                    out.headers_mut().append(k, v.clone());
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                }
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            }
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            out
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        }
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        Err(e) => (StatusCode::BAD_GATEWAY, format!("Spectra on the server did not answer: {e:#}")).into_response(),
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    }
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}
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#[cfg(test)]
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mod tests {
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    #[test]
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    fn the_link_points_at_the_proxy() {
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        assert_eq!(super::local_link("http://127.0.0.1:7350/signin?code=abc", 7351), "http://127.0.0.1:7351/signin?code=abc");
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    }
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}