Refactor puffin_http::Server to support client connect/disconnect callback

Cargo.toml

@@ -14,7 +14,6 @@ bincode = "1.3"
 byteorder = "1.0"
 cfg-if = "1.0.3"
 criterion = "0.7"
-crossbeam-channel = "0.5"
 eframe = { version = "0.32.2", default-features = false }
 egui = { version = "0.32.2", default-features = false }
 egui_extras = { version = "0.32.2", default-features = false }

puffin_http/Cargo.toml

@@ -15,7 +15,6 @@ include = ["**/*.rs", "Cargo.toml", "README.md"]
 
 [dependencies]
 anyhow.workspace = true
-crossbeam-channel.workspace = true
 log.workspace = true
 parking_lot.workspace = true
 puffin = { version = "0.19.1", path = "../puffin", features = [

puffin_http/examples/server.rs

@@ -8,10 +8,22 @@ fn main() {
         .init()
         .ok();
 
-    let server_addr = format!("127.0.0.1:{}", puffin_http::DEFAULT_PORT);
-    let _puffin_server = puffin_http::Server::new(&server_addr).unwrap();
-    eprintln!("Serving demo profile data on {server_addr}. Run `puffin_viewer` to view it.");
-    puffin::set_scopes_on(true);
+    let server_addr = format!("localhost:{}", puffin_http::DEFAULT_PORT);
+    let mut puffin_server = puffin_http::Server::new(&server_addr).unwrap();
+    eprintln!(
+        "Serving demo profile data on {}. Run `puffin_viewer --url \"{}\"` to view it.",
+        server_addr,
+        puffin_server.local_addr()
+    );
+    puffin_server.set_on_state_change(|has_clients| {
+        puffin::set_scopes_on(has_clients);
+        if has_clients {
+            eprintln!("Profiling enabled");
+        } else {
+            eprintln!("Profiling disabled");
+        }
+    });
+    let _puffin_server = puffin_server;
 
     let mut frame_counter = 0;
 

puffin_http/src/lib.rs

@@ -5,9 +5,9 @@
 //! When the server is started, [`puffin_viewer`](https://crates.io/crates/puffin_viewer) application can connect to it and display profiling information.
 //!
 //! ```
-//! let server_addr = format!("127.0.0.1:{}", puffin_http::DEFAULT_PORT);
-//! let _puffin_server = puffin_http::Server::new(&server_addr).unwrap();
-//! eprintln!("Serving demo profile data on {server_addr}. Run `puffin_viewer` to view it.");
+//! let puffin_server = puffin_http::Server::new("127.0.0.1:0").unwrap();
+//! let addr = puffin_server.local_addr();
+//! eprintln!("Serving demo profile data on {}. Run `puffin_viewer --url \"{}\"` to view it.", addr, addr);
 //! puffin::set_scopes_on(true);
 //! ```