fix(net,js): route op_fetch_url + ES module loader through proxy_url (#139) (#151)

Fixes the remaining two paths from #139: JS-level fetch()/XHR
(op_fetch_url) and dynamic ES module imports (ObscuraModuleLoader) both
built their reqwest clients with `Client::builder().build()` — no
proxy — so every JS-initiated network call silently bypassed
BrowserContext.proxy_url. (The third path, StealthHttpClient, was
already fixed in main: page.rs:61 uses with_proxy.)

Changes:

* obscura-net: expose ObscuraHttpClient::proxy_url() so callers outside
  the crate can route their own reqwest requests through the same
  upstream proxy. The field was already there — just lacked an accessor.

* obscura-js/module_loader: add `proxy_url: Option<String>` and
  `with_proxy(base_url, proxy_url)`. ObscuraModuleLoader::new keeps the
  pre-#139 direct-connection behaviour. load() builds a reqwest client
  per import, threading the proxy and bubbling up "Invalid module proxy"
  on bad URLs.

* obscura-js/ops.rs: replace the process-wide
  `static SHARED_HTTP_CLIENT: OnceLock<reqwest::Client>` (which could
  never be reconfigured after first call) with a per-request
  `build_request_client(proxy_url)` that pulls the configured proxy out
  of SharedState.http_client.proxy_url() each call. Per-request build
  cost is ~1ms vs the network round-trip, and we no longer have a
  global singleton that lies about its config.

* obscura-js/runtime: add ObscuraJsRuntime::with_base_url_and_proxy.
  with_base_url delegates to it with None so existing tests / callers
  are unaffected.

* obscura-browser/page.rs: thread context.proxy_url through to
  with_base_url_and_proxy when constructing the JS runtime.

crates/obscura-browser/src/page.rs

@@ -136,7 +136,14 @@ impl Page {
             return;
         }
 
-        let mut rt = ObscuraJsRuntime::with_base_url(&self.url_string());
+        // Thread the BrowserContext's proxy through to the ES-module loader
+        // and op_fetch_url so dynamic imports and JS fetch() honour the
+        // configured upstream proxy (#139). When proxy_url is None this is
+        // equivalent to with_base_url() (direct connection).
+        let mut rt = ObscuraJsRuntime::with_base_url_and_proxy(
+            &self.url_string(),
+            self.context.proxy_url.clone(),
+        );
         rt.set_url(&self.url_string());
         rt.set_title(&self.title);
 

crates/obscura-js/src/module_loader.rs

@@ -10,12 +10,21 @@ use deno_core::RequestedModuleType;
 
 pub struct ObscuraModuleLoader {
     pub base_url: String,
+    /// Proxy URL threaded through to every dynamic ES-module fetch (#139).
+    /// `None` keeps the pre-#139 direct-connection behaviour for callers
+    /// that haven't been updated.
+    pub proxy_url: Option<String>,
 }
 
 impl ObscuraModuleLoader {
     pub fn new(base_url: &str) -> Self {
+        Self::with_proxy(base_url, None)
+    }
+
+    pub fn with_proxy(base_url: &str, proxy_url: Option<String>) -> Self {
         ObscuraModuleLoader {
             base_url: base_url.to_string(),
+            proxy_url,
         }
     }
 }
@@ -52,13 +61,32 @@ impl ModuleLoader for ObscuraModuleLoader {
         _requested_module_type: RequestedModuleType,
     ) -> ModuleLoadResponse {
         let url = module_specifier.to_string();
+        // Capture the loader's proxy here so the async closure below owns a
+        // plain Option<String> rather than borrowing &self across an `await`.
+        let proxy_url = self.proxy_url.clone();
 
         ModuleLoadResponse::Async(Pin::from(Box::new(async move {
-            let client = reqwest::Client::builder()
+            let mut builder = reqwest::Client::builder();
+            if let Some(ref proxy) = proxy_url {
+                match reqwest::Proxy::all(proxy) {
+                    Ok(p) => builder = builder.proxy(p),
+                    Err(e) => {
+                        return Err(io_err(format!(
+                            "Invalid module proxy '{}': {}",
+                            proxy, e
+                        )));
+                    }
+                }
+            }
+            let client = builder
                 .build()
                 .map_err(|e| io_err(format!("HTTP client error: {}", e)))?;
 
-            tracing::debug!("Loading ES module: {}", url);
+            tracing::debug!(
+                "Loading ES module: {} (proxy: {})",
+                url,
+                proxy_url.as_deref().unwrap_or("direct")
+            );
 
             let resp = client
                 .get(&url)

crates/obscura-js/src/ops.rs

@@ -1,7 +1,7 @@
 use std::cell::RefCell;
 use std::collections::HashMap;
 use std::rc::Rc;
-use std::sync::{Arc, OnceLock};
+use std::sync::Arc;
 
 use deno_core::op2;
 use deno_core::OpState;
@@ -281,14 +281,25 @@ fn op_console_msg(state: &OpState, #[string] level: &str, #[string] msg: &str) {
     }
 }
 
-static SHARED_HTTP_CLIENT: OnceLock<reqwest::Client> = OnceLock::new();
-
-fn get_shared_client() -> &'static reqwest::Client {
-    SHARED_HTTP_CLIENT.get_or_init(|| {
-        reqwest::Client::builder()
-            .build()
-            .expect("failed to build shared reqwest::Client")
-    })
+// op_fetch_url backs JS-level `fetch()` and XHR. Pre-#139 it used a
+// process-wide `OnceLock<reqwest::Client>` initialised with no proxy, so
+// every JS network call bypassed the configured upstream proxy. We now
+// build a client per request, threading whatever `proxy_url` the page's
+// ObscuraHttpClient was configured with.
+//
+// The per-request build cost is negligible (≪1ms) compared with the actual
+// network round-trip; the simplification is worth not having to invalidate
+// a cache when the proxy is reconfigured between fetches.
+fn build_request_client(proxy_url: Option<&str>) -> Result<reqwest::Client, String> {
+    let mut builder = reqwest::Client::builder();
+    if let Some(proxy) = proxy_url {
+        let p = reqwest::Proxy::all(proxy)
+            .map_err(|e| format!("Invalid op_fetch_url proxy '{}': {}", proxy, e))?;
+        builder = builder.proxy(p);
+    }
+    builder
+        .build()
+        .map_err(|e| format!("failed to build reqwest::Client: {}", e))
 }
 
 #[op2(async)]
@@ -317,7 +328,7 @@ async fn op_fetch_url(
         }
     }
 
-    let (cookie_jar, in_flight, intercept_tx) = {
+    let (cookie_jar, in_flight, intercept_tx, proxy_url) = {
         let state_borrow = state.borrow();
         let gs = state_borrow.borrow::<SharedState>().clone();
         let mut gs = gs.borrow_mut();
@@ -334,6 +345,10 @@ async fn op_fetch_url(
         }
         let jar = gs.cookie_jar.clone();
         let in_flight = gs.http_client.as_ref().map(|c| c.in_flight.clone());
+        // #139: thread the configured proxy through to the per-request
+        // reqwest::Client. Without this, op_fetch_url silently bypasses
+        // BrowserContext.proxy_url for every JS fetch() / XHR call.
+        let proxy_url = gs.http_client.as_ref().and_then(|c| c.proxy_url().map(|s| s.to_string()));
         tracing::debug!("op_fetch_url: intercept_enabled={}, has_tx={}", gs.intercept_enabled, gs.intercept_tx.is_some());
         let itx = if gs.intercept_enabled {
             gs.intercept_counter += 1;
@@ -341,7 +356,7 @@ async fn op_fetch_url(
         } else {
             None
         };
-        (jar, in_flight, itx)
+        (jar, in_flight, itx, proxy_url)
     };
 
     if let Some((tx, request_id)) = intercept_tx {
@@ -385,7 +400,8 @@ async fn op_fetch_url(
         }
     }
 
-    let client = get_shared_client();
+    let client = build_request_client(proxy_url.as_deref())
+        .map_err(deno_error::JsErrorBox::generic)?;
 
     let request_origin = url::Url::parse(&url)
         .ok()

crates/obscura-js/src/runtime.rs

@@ -33,10 +33,17 @@ impl ObscuraJsRuntime {
     }
 
     pub fn with_base_url(base_url: &str) -> Self {
+        Self::with_base_url_and_proxy(base_url, None)
+    }
+
+    /// Construct a runtime whose ES-module loader routes dynamic imports
+    /// through `proxy_url` (#139). `None` is equivalent to `with_base_url`
+    /// (direct connection).
+    pub fn with_base_url_and_proxy(base_url: &str, proxy_url: Option<String>) -> Self {
         let state = Rc::new(RefCell::new(ObscuraState::new()));
         let state_clone = state.clone();
 
-        let module_loader = Rc::new(ObscuraModuleLoader::new(base_url));
+        let module_loader = Rc::new(ObscuraModuleLoader::with_proxy(base_url, proxy_url));
 
         let mut runtime = JsRuntime::new(RuntimeOptions {
             extensions: vec![build_extension()],
@@ -1589,4 +1596,61 @@ mod tests {
         assert_eq!(inf, serde_json::Value::Null);
     }
 
+    // Issue #139 — proxy_url must thread through to both the ES-module
+    // loader (module_loader.rs) and op_fetch_url's reqwest client
+    // (ops.rs::build_request_client). Pre-fix both built clients with
+    // `Client::builder().build()` — no proxy — so JS fetch/XHR and
+    // dynamic imports silently bypassed BrowserContext.proxy_url.
+    //
+    // Phase 5.5 RED check: each test references a symbol that does NOT
+    // exist on main (proxy_url() accessor, with_proxy ctor,
+    // with_base_url_and_proxy ctor), so the tests fail to compile without
+    // the prod fix.
+    #[test]
+    fn http_client_round_trips_proxy_url() {
+        use obscura_net::{CookieJar, ObscuraHttpClient};
+        let jar = std::sync::Arc::new(CookieJar::new());
+        let configured =
+            ObscuraHttpClient::with_options(jar.clone(), Some("http://proxy.test:8080"));
+        assert_eq!(
+            configured.proxy_url(),
+            Some("http://proxy.test:8080"),
+            "proxy_url() must expose the value passed to with_options"
+        );
+
+        let direct = ObscuraHttpClient::with_options(jar, None);
+        assert_eq!(
+            direct.proxy_url(),
+            None,
+            "proxy_url() must return None when no proxy was configured"
+        );
+    }
+
+    #[test]
+    fn module_loader_stores_proxy_for_dynamic_imports() {
+        use crate::module_loader::ObscuraModuleLoader;
+        let loader = ObscuraModuleLoader::with_proxy(
+            "https://example.com/",
+            Some("http://proxy.test:8080".to_string()),
+        );
+        assert_eq!(loader.proxy_url.as_deref(), Some("http://proxy.test:8080"));
+        assert_eq!(loader.base_url, "https://example.com/");
+
+        // Default constructor must keep the historical "no proxy" behaviour.
+        let direct = ObscuraModuleLoader::new("https://example.com/");
+        assert_eq!(direct.proxy_url, None);
+    }
+
+    #[test]
+    fn runtime_with_base_url_and_proxy_constructs_successfully() {
+        // Sanity-check the public ctor that page.rs uses to thread proxy
+        // through to the module loader. Direct (None) and proxied paths
+        // must both initialise the JS environment.
+        let _direct = ObscuraJsRuntime::with_base_url_and_proxy("https://example.com/", None);
+        let _proxied = ObscuraJsRuntime::with_base_url_and_proxy(
+            "https://example.com/",
+            Some("http://proxy.test:8080".to_string()),
+        );
+    }
+
 }

crates/obscura-net/src/client.rs

@@ -212,6 +212,14 @@ impl ObscuraHttpClient {
         }).await
     }
 
+    /// Read-only accessor for the proxy URL the client was configured with
+    /// (if any). Exposed so callers outside the `obscura-net` crate — notably
+    /// `op_fetch_url` in `obscura-js` (#139) — can route their own reqwest
+    /// requests through the same upstream proxy.
+    pub fn proxy_url(&self) -> Option<&str> {
+        self.proxy_url.as_deref()
+    }
+
     pub async fn fetch(&self, url: &Url) -> Result<Response, ObscuraNetError> {
         self.fetch_with_method(Method::GET, url, None).await
     }