Replace host_web_viewer method with `WebViewerConfig::host_web_view…

…er` (#7553)

### What

This makes it easier to host Rerun webviewer.

Usage example
```rust
    rerun::web_viewer::WebViewerConfig {
        source_url: Some(
            "https://app.rerun.io/version/0.18.1/examples/arkit_scenes.rrd".to_owned(),
        ),
        force_wgpu_backend: Some("webgl".to_owned()),
        ..Default::default()
    }
    .host_web_viewer()?
    .block();
```

This is a followup of this comment
#7537 (comment)
Opted to not implement a builder as well since I felt it's not worth the
hassle here, above snippet looks perfectly fine without a builder.

### 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 examples from latest `main` build:
[rerun.io/viewer](https://rerun.io/viewer/pr/7553?manifest_url=https://app.rerun.io/version/main/examples_manifest.json)
* Using full set of examples from `nightly` build:
[rerun.io/viewer](https://rerun.io/viewer/pr/7553?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
* [x] If applicable, add a new check to the [release
checklist](https://github.com/rerun-io/rerun/blob/main/tests/python/release_checklist)!
* [x] If have noted any breaking changes to the log API in
`CHANGELOG.md` and the migration guide

- [PR Build Summary](https://build.rerun.io/pr/7553)
- [Recent benchmark results](https://build.rerun.io/graphs/crates.html)
- [Wasm size tracking](https://build.rerun.io/graphs/sizes.html)

To run all checks from `main`, comment on the PR with `@rerun-bot
full-check`.

crates/top/re_sdk/src/web_viewer.rs

@@ -106,41 +106,107 @@ impl Drop for WebViewerSink {
 
 // ----------------------------------------------------------------------------
 
-/// Helper to spawn an instance of the [`WebViewerServer`].
-/// This serves the HTTP+Wasm+JS files that make up the web-viewer.
-///
-/// Optionally opens a browser with the web-viewer and connects to the provided `target_url`.
-/// This url could be a hosted RRD file or a `ws://` url to a running [`re_ws_comms::RerunServer`].
-///
-/// Note: this does not include the websocket server.
-///
-/// - `force_wgpu_backend` is an optional string to force a specific backend, either `webgl` or `webgpu`.
+/// Helper to spawn an instance of the [`WebViewerServer`] and configure a webviewer url.
 #[cfg(feature = "web_viewer")]
-pub fn host_web_viewer(
-    bind_ip: &str,
-    web_port: WebViewerServerPort,
-    force_wgpu_backend: Option<String>,
-    video_decoder: Option<String>,
-    open_browser: bool,
-    source_url: &str,
-) -> anyhow::Result<WebViewerServer> {
-    let web_server = WebViewerServer::new(bind_ip, web_port)?;
-    let http_web_viewer_url = web_server.server_url();
-
-    let mut viewer_url = format!("{http_web_viewer_url}?url={source_url}");
-    if let Some(force_graphics) = force_wgpu_backend {
-        viewer_url = format!("{viewer_url}&renderer={force_graphics}");
-    }
-    if let Some(video_decoder) = video_decoder {
-        viewer_url = format!("{viewer_url}&video_decoder={video_decoder}");
-    }
+pub struct WebViewerConfig {
+    /// Ip to which the http server is bound.
+    ///
+    /// Defaults to 0.0.0.0
+    pub bind_ip: String,
+
+    /// The port to which the webviewer should bind.
+    ///
+    /// Defaults to [`WebViewerServerPort::AUTO`].
+    pub web_port: WebViewerServerPort,
+
+    /// The url from which a spawned webviewer should source
+    ///
+    /// This url could be a hosted RRD file or a `ws://` url to a running [`re_ws_comms::RerunServer`].
+    /// Has no effect if [`Self::open_browser`] is false.
+    pub source_url: Option<String>,
+
+    /// If set, adjusts the browser url to force a specific backend, either `webgl` or `webgpu`.
+    ///
+    /// Has no effect if [`Self::open_browser`] is false.
+    pub force_wgpu_backend: Option<String>,
+
+    /// If set, adjusts the browser url to set the video decoder setting, either `auto`, `prefer_software` or `prefer_hardware`.
+    ///
+    /// Has no effect if [`Self::open_browser`] is false.
+    pub video_decoder: Option<String>,
+
+    /// If set to `true`, opens the default browser after hosting the webviewer.
+    ///
+    /// Defaults to `true`.
+    pub open_browser: bool,
+}
 
-    re_log::info!("Hosting a web-viewer at {viewer_url}");
-    if open_browser {
-        webbrowser::open(&viewer_url).ok();
+#[cfg(feature = "web_viewer")]
+impl Default for WebViewerConfig {
+    fn default() -> Self {
+        Self {
+            bind_ip: "0.0.0.0".to_owned(),
+            web_port: WebViewerServerPort::AUTO,
+            source_url: None,
+            force_wgpu_backend: None,
+            video_decoder: None,
+            open_browser: true,
+        }
     }
+}
 
-    Ok(web_server)
+#[cfg(feature = "web_viewer")]
+impl WebViewerConfig {
+    /// Helper to spawn an instance of the [`WebViewerServer`].
+    /// This serves the HTTP+Wasm+JS files that make up the web-viewer.
+    ///
+    /// The server will immediately start listening for incoming connections
+    /// and stop doing so when the returned [`WebViewerServer`] is dropped.
+    ///
+    /// Note: this does not include the websocket server.
+    pub fn host_web_viewer(self) -> Result<WebViewerServer, WebViewerServerError> {
+        let Self {
+            bind_ip,
+            source_url,
+            web_port,
+            force_wgpu_backend,
+            video_decoder,
+            open_browser,
+        } = self;
+
+        let web_server = WebViewerServer::new(&bind_ip, web_port)?;
+        let http_web_viewer_url = web_server.server_url();
+
+        let mut viewer_url = http_web_viewer_url;
+
+        let mut first_arg = true;
+        let mut append_argument = |arg| {
+            let arg_delimiter = if first_arg {
+                first_arg = false;
+                "?"
+            } else {
+                "&"
+            };
+            viewer_url = format!("{viewer_url}{arg_delimiter}{arg}");
+        };
+
+        if let Some(source_url) = source_url {
+            append_argument(format!("url={source_url}"));
+        }
+        if let Some(force_graphics) = force_wgpu_backend {
+            append_argument(format!("renderer={force_graphics}"));
+        }
+        if let Some(video_decoder) = video_decoder {
+            append_argument(format!("video_decoder={video_decoder}"));
+        }
+
+        re_log::info!("Hosting a web-viewer at {viewer_url}");
+        if open_browser {
+            webbrowser::open(&viewer_url).ok();
+        }
+
+        Ok(web_server)
+    }
 }
 
 // ----------------------------------------------------------------------------

crates/top/rerun/src/commands/entrypoint.rs

@@ -8,7 +8,7 @@ use re_smart_channel::{ReceiveSet, Receiver, SmartMessagePayload};
 use crate::{commands::RrdCommands, CallSource};
 
 #[cfg(feature = "web_viewer")]
-use re_sdk::web_viewer::host_web_viewer;
+use re_sdk::web_viewer::WebViewerConfig;
 #[cfg(feature = "web_viewer")]
 use re_web_viewer_server::WebViewerServerPort;
 #[cfg(feature = "server")]
@@ -680,14 +680,16 @@ fn run_impl(
             if let DataSource::WebSocketAddr(rerun_server_ws_url) = data_sources[0].clone() {
                 // Special case! We are connecting a web-viewer to a web-socket address.
                 // Instead of piping, just host a web-viewer that connects to the web-socket directly:
-                host_web_viewer(
-                    &args.bind,
-                    args.web_viewer_port,
-                    args.renderer,
-                    args.video_decoder,
-                    true,
-                    &rerun_server_ws_url,
-                )?
+
+                WebViewerConfig {
+                    bind_ip: args.bind,
+                    web_port: args.web_viewer_port,
+                    source_url: Some(rerun_server_ws_url),
+                    force_wgpu_backend: args.renderer,
+                    video_decoder: args.video_decoder,
+                    open_browser: true,
+                }
+                .host_web_viewer()?
                 .block();
 
                 return Ok(());
@@ -755,14 +757,15 @@ fn run_impl(
                 let open_browser = args.web_viewer;
 
                 // This is the server that serves the Wasm+HTML:
-                host_web_viewer(
-                    &args.bind,
-                    args.web_viewer_port,
-                    args.renderer,
-                    args.video_decoder,
+                WebViewerConfig {
+                    bind_ip: args.bind,
+                    web_port: args.web_viewer_port,
+                    source_url: Some(_ws_server.server_url()),
+                    force_wgpu_backend: args.renderer,
+                    video_decoder: args.video_decoder,
                     open_browser,
-                    &_ws_server.server_url(),
-                )?
+                }
+                .host_web_viewer()?
                 .block(); // dropping should stop the server
             }