Web: Support multiple .rrd URLs (#4740)

### What

Fixes #4630

New API can be seen here:
https://github.com/rerun-io/web-viewer-react-example/blob/main/src/App.tsx

### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)
* [x] I have tested the web demo (if applicable):
* Using newly built examples:
[app.rerun.io](https://app.rerun.io/pr/4740/index.html)
* Using examples from latest `main` build:
[app.rerun.io](https://app.rerun.io/pr/4740/index.html?manifest_url=https://app.rerun.io/version/main/examples_manifest.json)
* Using full set of examples from `nightly` build:
[app.rerun.io](https://app.rerun.io/pr/4740/index.html?manifest_url=https://app.rerun.io/version/nightly/examples_manifest.json)
* [x] The PR title and labels are set such as to maximize their
usefulness for the next release's CHANGELOG

- [PR Build Summary](https://build.rerun.io/pr/4740)
- [Docs
preview](https://rerun.io/preview/165842ec644787f1b959e93fd14071c3ac7b6986/docs)
<!--DOCS-PREVIEW-->
- [Examples
preview](https://rerun.io/preview/165842ec644787f1b959e93fd14071c3ac7b6986/examples)
<!--EXAMPLES-PREVIEW-->
- [Recent benchmark results](https://build.rerun.io/graphs/crates.html)
- [Wasm size tracking](https://build.rerun.io/graphs/sizes.html)

crates/re_log/src/setup.rs

@@ -59,6 +59,14 @@ pub fn setup_native_logging() {
 
 #[cfg(target_arch = "wasm32")]
 pub fn setup_web_logging() {
+    use std::sync::atomic::{AtomicBool, Ordering};
+
+    static LOG_INIT: AtomicBool = AtomicBool::new(false);
+    if LOG_INIT.load(Ordering::SeqCst) {
+        return;
+    }
+    LOG_INIT.store(true, Ordering::SeqCst);
+
     crate::multi_logger::init().expect("Failed to set logger");
     log::set_max_level(log::LevelFilter::Debug);
     crate::add_boxed_logger(Box::new(crate::web_logger::WebLogger::new(

crates/re_log_encoding/src/stream_rrd_from_http.rs

@@ -21,14 +21,24 @@ pub fn stream_rrd_from_http_to_channel(
                 on_msg();
             }
             match msg {
-                HttpMessage::LogMsg(msg) => tx.send(msg).warn_on_err_once("failed to send message"),
+                HttpMessage::LogMsg(msg) => {
+                    if tx.send(msg).is_ok() {
+                        ControlFlow::Continue(())
+                    } else {
+                        re_log::info!("Failed to send log message to viewer - closing");
+                        ControlFlow::Break(())
+                    }
+                }
                 HttpMessage::Success => {
-                    tx.quit(None).warn_on_err_once("failed to send quit marker")
+                    tx.quit(None).warn_on_err_once("failed to send quit marker");
+                    ControlFlow::Break(())
+                }
+                HttpMessage::Failure(err) => {
+                    tx.quit(Some(err))
+                        .warn_on_err_once("failed to send quit marker");
+                    ControlFlow::Break(())
                 }
-                HttpMessage::Failure(err) => tx
-                    .quit(Some(err))
-                    .warn_on_err_once("failed to send quit marker"),
-            };
+            }
         }),
     );
     rx
@@ -46,7 +56,7 @@ pub enum HttpMessage {
     Failure(Box<dyn std::error::Error + Send + Sync>),
 }
 
-pub type HttpMessageCallback = dyn Fn(HttpMessage) + Send + Sync;
+pub type HttpMessageCallback = dyn Fn(HttpMessage) -> ControlFlow<()> + Send + Sync;
 
 pub fn stream_rrd_from_http(url: String, on_msg: Arc<HttpMessageCallback>) {
     re_log::debug!("Downloading .rrd file from {url:?}…");
@@ -69,41 +79,40 @@ pub fn stream_rrd_from_http(url: String, on_msg: Arc<HttpMessageCallback>) {
                         on_msg(HttpMessage::Failure(
                             format!("Failed to fetch .rrd file from {url}: {status} {status_text}")
                                 .into(),
-                        ));
-                        ControlFlow::Break(())
+                        ))
                     }
                 }
                 ehttp::streaming::Part::Chunk(chunk) => {
                     if chunk.is_empty() {
                         re_log::debug!("Finished decoding .rrd file from {url:?}…");
-                        on_msg(HttpMessage::Success);
-                        return ControlFlow::Break(());
+                        return on_msg(HttpMessage::Success);
                     }
 
                     re_tracing::profile_scope!("decoding_rrd_stream");
                     decoder.borrow_mut().push_chunk(chunk);
                     loop {
                         match decoder.borrow_mut().try_read() {
                             Ok(message) => match message {
-                                Some(message) => on_msg(HttpMessage::LogMsg(message)),
+                                Some(message) => {
+                                    // only return if the callback asks us to
+                                    if on_msg(HttpMessage::LogMsg(message)).is_break() {
+                                        return ControlFlow::Break(());
+                                    }
+                                }
                                 None => return ControlFlow::Continue(()),
                             },
                             Err(err) => {
-                                on_msg(HttpMessage::Failure(
+                                return on_msg(HttpMessage::Failure(
                                     format!("Failed to fetch .rrd file from {url}: {err}").into(),
-                                ));
-                                return ControlFlow::Break(());
+                                ))
                             }
                         }
                     }
                 }
             },
-            Err(err) => {
-                on_msg(HttpMessage::Failure(
-                    format!("Failed to fetch .rrd file from {url}: {err}").into(),
-                ));
-                ControlFlow::Break(())
-            }
+            Err(err) => on_msg(HttpMessage::Failure(
+                format!("Failed to fetch .rrd file from {url}: {err}").into(),
+            )),
         }
     });
 }

crates/re_smart_channel/src/receive_set.rs

@@ -36,6 +36,19 @@ impl<T: Send> ReceiveSet<T> {
         self.receivers.lock().retain(|r| r.source() != source);
     }
 
+    /// Disconnect from any channel with a source pointing at this `uri`.
+    #[cfg(target_arch = "wasm32")]
+    pub fn remove_by_uri(&self, uri: &str) {
+        self.receivers.lock().retain(|r| match r.source() {
+            // retain only sources which:
+            // - aren't network sources
+            // - don't point at the given `uri`
+            SmartChannelSource::RrdHttpStream { url } => url != uri,
+            SmartChannelSource::WsClient { ws_server_url } => ws_server_url != uri,
+            _ => true,
+        });
+    }
+
     /// List of connected receiver sources.
     ///
     /// This gets culled after calling one of the `recv` methods.

crates/re_viewer/src/app.rs

@@ -1184,6 +1184,11 @@ impl eframe::App for App {
             frame_start.elapsed().as_secs_f32(),
         );
     }
+
+    #[cfg(target_arch = "wasm32")]
+    fn as_any_mut(&mut self) -> Option<&mut dyn std::any::Any> {
+        Some(&mut *self)
+    }
 }
 
 /// Add built-in space views to the registry.

crates/re_viewer/src/store_hub.rs

@@ -275,6 +275,28 @@ impl StoreHub {
         self.store_bundle.contains_recording(id)
     }
 
+    /// Remove any recordings with a network source pointing at this `uri`.
+    #[cfg(target_arch = "wasm32")]
+    pub fn remove_recording_by_uri(&mut self, uri: &str) {
+        self.store_bundle.entity_dbs.retain(|_, db| {
+            let Some(data_source) = &db.data_source else {
+                // no data source, keep
+                return true;
+            };
+
+            // retain only sources which:
+            // - aren't network sources
+            // - don't point at the given `uri`
+            match data_source {
+                re_smart_channel::SmartChannelSource::RrdHttpStream { url } => url != uri,
+                re_smart_channel::SmartChannelSource::WsClient { ws_server_url } => {
+                    ws_server_url != uri
+                }
+                _ => true,
+            }
+        });
+    }
+
     /// Persist any in-use blueprints to durable storage.
     // TODO(#2579): implement persistence for web
     #[allow(clippy::unnecessary_wraps)]

crates/re_viewer/src/web.rs

@@ -2,6 +2,7 @@
 
 use eframe::wasm_bindgen::{self, prelude::*};
 
+use std::ops::ControlFlow;
 use std::sync::Arc;
 
 use re_log::ResultExt as _;
@@ -80,6 +81,26 @@ impl WebHandle {
     pub fn panic_callstack(&self) -> Option<String> {
         self.runner.panic_summary().map(|s| s.callstack())
     }
+
+    #[wasm_bindgen]
+    pub fn add_receiver(&self, url: &str) {
+        let Some(mut app) = self.runner.app_mut::<crate::App>() else {
+            return;
+        };
+        let rx = url_to_receiver(url, app.re_ui.egui_ctx.clone());
+        app.add_receiver(rx);
+    }
+
+    #[wasm_bindgen]
+    pub fn remove_receiver(&self, url: &str) {
+        let Some(mut app) = self.runner.app_mut::<crate::App>() else {
+            return;
+        };
+        app.msg_receive_set().remove_by_uri(url);
+        if let Some(store_hub) = app.store_hub.as_mut() {
+            store_hub.remove_recording_by_uri(url);
+        }
+    }
 }
 
 fn create_app(
@@ -102,11 +123,6 @@ fn create_app(
     let re_ui = crate::customize_eframe(cc);
 
     let egui_ctx = cc.egui_ctx.clone();
-    let wake_up_ui_on_msg = Box::new(move || {
-        // Spend a few more milliseconds decoding incoming messages,
-        // then trigger a repaint (https://github.com/rerun-io/rerun/issues/963):
-        egui_ctx.request_repaint_after(std::time::Duration::from_millis(10));
-    });
 
     let mut app = crate::App::new(build_info, &app_env, startup_options, re_ui, cc.storage);
 
@@ -126,50 +142,67 @@ fn create_app(
         None => query_map.get("url").map(String::as_str),
     };
     if let Some(url) = url {
-        let rx = match categorize_uri(url) {
-            EndpointCategory::HttpRrd(url) => {
-                re_log_encoding::stream_rrd_from_http::stream_rrd_from_http_to_channel(
-                    url,
-                    Some(wake_up_ui_on_msg),
-                )
-            }
-            EndpointCategory::WebEventListener => {
-                // Process an rrd when it's posted via `window.postMessage`
-                let (tx, rx) = re_smart_channel::smart_channel(
-                    re_smart_channel::SmartMessageSource::RrdWebEventCallback,
-                    re_smart_channel::SmartChannelSource::RrdWebEventListener,
-                );
-                re_log_encoding::stream_rrd_from_http::stream_rrd_from_event_listener(Arc::new({
-                    move |msg| {
-                        wake_up_ui_on_msg();
-                        use re_log_encoding::stream_rrd_from_http::HttpMessage;
-                        match msg {
-                            HttpMessage::LogMsg(msg) => {
-                                tx.send(msg).warn_on_err_once("failed to send message")
-                            }
-                            HttpMessage::Success => {
-                                tx.quit(None).warn_on_err_once("failed to send quit marker")
-                            }
-                            HttpMessage::Failure(err) => tx
-                                .quit(Some(err))
-                                .warn_on_err_once("failed to send quit marker"),
-                        };
-                    }
-                }));
-                rx
-            }
-            EndpointCategory::WebSocket(url) => {
-                re_data_source::connect_to_ws_url(&url, Some(wake_up_ui_on_msg)).unwrap_or_else(
-                    |err| panic!("Failed to connect to WebSocket server at {url}: {err}"),
-                )
-            }
-        };
+        let rx = url_to_receiver(url, egui_ctx.clone());
         app.add_receiver(rx);
     }
 
     app
 }
 
+fn url_to_receiver(
+    url: &str,
+    egui_ctx: egui::Context,
+) -> re_smart_channel::Receiver<re_log_types::LogMsg> {
+    let ui_waker = Box::new(move || {
+        // Spend a few more milliseconds decoding incoming messages,
+        // then trigger a repaint (https://github.com/rerun-io/rerun/issues/963):
+        egui_ctx.request_repaint_after(std::time::Duration::from_millis(10));
+    });
+    match categorize_uri(url) {
+        EndpointCategory::HttpRrd(url) => {
+            re_log_encoding::stream_rrd_from_http::stream_rrd_from_http_to_channel(
+                url,
+                Some(ui_waker),
+            )
+        }
+        EndpointCategory::WebEventListener => {
+            // Process an rrd when it's posted via `window.postMessage`
+            let (tx, rx) = re_smart_channel::smart_channel(
+                re_smart_channel::SmartMessageSource::RrdWebEventCallback,
+                re_smart_channel::SmartChannelSource::RrdWebEventListener,
+            );
+            re_log_encoding::stream_rrd_from_http::stream_rrd_from_event_listener(Arc::new({
+                move |msg| {
+                    ui_waker();
+                    use re_log_encoding::stream_rrd_from_http::HttpMessage;
+                    match msg {
+                        HttpMessage::LogMsg(msg) => {
+                            if tx.send(msg).is_ok() {
+                                ControlFlow::Continue(())
+                            } else {
+                                re_log::info!("Failed to send log message to viewer - closing");
+                                ControlFlow::Break(())
+                            }
+                        }
+                        HttpMessage::Success => {
+                            tx.quit(None).warn_on_err_once("failed to send quit marker");
+                            ControlFlow::Break(())
+                        }
+                        HttpMessage::Failure(err) => {
+                            tx.quit(Some(err))
+                                .warn_on_err_once("failed to send quit marker");
+                            ControlFlow::Break(())
+                        }
+                    }
+                }
+            }));
+            rx
+        }
+        EndpointCategory::WebSocket(url) => re_data_source::connect_to_ws_url(&url, Some(ui_waker))
+            .unwrap_or_else(|err| panic!("Failed to connect to WebSocket server at {url}: {err}")),
+    }
+}
+
 /// Used to set the "email" property in the analytics config,
 /// in the same way as `rerun analytics email [email protected]`.
 ///