From b4be616de083cc427b1e0466fe54f8a239ef374a Mon Sep 17 00:00:00 2001
From: Timon <me@timon.zip>
Date: Thu, 25 Sep 2025 10:42:07 +0000
Subject: [PATCH] Desktop: Browser console message forwarding (#3193)

* browser console message forwarding

* replace target to make it easy to identify browser console messages

* use warn as per review comment
---
 desktop/src/cef/internal.rs                   |  2 +
 .../cef/internal/browser_process_client.rs    | 10 ++-
 desktop/src/cef/internal/display_handler.rs   | 65 +++++++++++++++++++
 desktop/src/main.rs                           |  2 +-
 4 files changed, 77 insertions(+), 2 deletions(-)
 create mode 100644 desktop/src/cef/internal/display_handler.rs

diff --git a/desktop/src/cef/internal.rs b/desktop/src/cef/internal.rs
index 47f0ff202..4a2559ac1 100644
--- a/desktop/src/cef/internal.rs
+++ b/desktop/src/cef/internal.rs
@@ -10,6 +10,8 @@ mod render_process_v8_handler;
 mod resource_handler;
 mod scheme_handler_factory;
 
+mod display_handler;
+
 pub(super) mod render_handler;
 pub(super) mod task;
 
diff --git a/desktop/src/cef/internal/browser_process_client.rs b/desktop/src/cef/internal/browser_process_client.rs
index 1ed5eeb12..f98ff0103 100644
--- a/desktop/src/cef/internal/browser_process_client.rs
+++ b/desktop/src/cef/internal/browser_process_client.rs
@@ -1,16 +1,18 @@
 use cef::rc::{Rc, RcImpl};
 use cef::sys::{_cef_client_t, cef_base_ref_counted_t};
-use cef::{ImplClient, LifeSpanHandler, RenderHandler, WrapClient};
+use cef::{DisplayHandler, ImplClient, LifeSpanHandler, RenderHandler, WrapClient};
 
 use crate::cef::CefEventHandler;
 use crate::cef::ipc::{MessageType, UnpackMessage, UnpackedMessage};
 
 use super::browser_process_life_span_handler::BrowserProcessLifeSpanHandlerImpl;
+use super::display_handler::DisplayHandlerImpl;
 
 pub(crate) struct BrowserProcessClientImpl<H: CefEventHandler> {
 	object: *mut RcImpl<_cef_client_t, Self>,
 	render_handler: RenderHandler,
 	event_handler: H,
+	display_handler: DisplayHandler,
 }
 impl<H: CefEventHandler> BrowserProcessClientImpl<H> {
 	pub(crate) fn new(render_handler: RenderHandler, event_handler: H) -> Self {
@@ -18,6 +20,7 @@ impl<H: CefEventHandler> BrowserProcessClientImpl<H> {
 			object: std::ptr::null_mut(),
 			render_handler,
 			event_handler,
+			display_handler: DisplayHandler::new(DisplayHandlerImpl::new()),
 		}
 	}
 }
@@ -57,6 +60,10 @@ impl<H: CefEventHandler> ImplClient for BrowserProcessClientImpl<H> {
 		Some(LifeSpanHandler::new(BrowserProcessLifeSpanHandlerImpl::new()))
 	}
 
+	fn display_handler(&self) -> Option<cef::DisplayHandler> {
+		Some(self.display_handler.clone())
+	}
+
 	fn get_raw(&self) -> *mut _cef_client_t {
 		self.object.cast()
 	}
@@ -72,6 +79,7 @@ impl<H: CefEventHandler> Clone for BrowserProcessClientImpl<H> {
 			object: self.object,
 			render_handler: self.render_handler.clone(),
 			event_handler: self.event_handler.clone(),
+			display_handler: self.display_handler.clone(),
 		}
 	}
 }
diff --git a/desktop/src/cef/internal/display_handler.rs b/desktop/src/cef/internal/display_handler.rs
new file mode 100644
index 000000000..5ca8d5d53
--- /dev/null
+++ b/desktop/src/cef/internal/display_handler.rs
@@ -0,0 +1,65 @@
+use cef::rc::{Rc, RcImpl};
+use cef::sys::{_cef_display_handler_t, cef_base_ref_counted_t, cef_log_severity_t::*};
+use cef::{CefString, ImplDisplayHandler, WrapDisplayHandler};
+
+pub(crate) struct DisplayHandlerImpl {
+	object: *mut RcImpl<_cef_display_handler_t, Self>,
+}
+
+impl DisplayHandlerImpl {
+	pub fn new() -> Self {
+		Self { object: std::ptr::null_mut() }
+	}
+}
+
+impl ImplDisplayHandler for DisplayHandlerImpl {
+	fn on_console_message(
+		&self,
+		_browser: Option<&mut cef::Browser>,
+		level: cef::LogSeverity,
+		message: Option<&CefString>,
+		source: Option<&CefString>,
+		line: ::std::os::raw::c_int,
+	) -> ::std::os::raw::c_int {
+		let message = message.map(|m| m.to_string()).unwrap_or_default();
+		let source = source.map(|s| s.to_string()).unwrap_or_default();
+		let line = line as i64;
+		let browser_source = format!("{source}:{line}");
+		static BROWSER: &str = "browser";
+		match level.as_ref() {
+			LOGSEVERITY_FATAL | LOGSEVERITY_ERROR => tracing::error!(target: BROWSER, "{browser_source} {message}"),
+			LOGSEVERITY_WARNING => tracing::warn!(target: BROWSER, "{browser_source} {message}"),
+			LOGSEVERITY_INFO => tracing::info!(target: BROWSER, "{browser_source} {message}"),
+			LOGSEVERITY_DEFAULT | LOGSEVERITY_VERBOSE => tracing::debug!(target: BROWSER, "{browser_source} {message}"),
+			_ => tracing::trace!(target: BROWSER, "{browser_source} {message}"),
+		}
+		0
+	}
+
+	fn get_raw(&self) -> *mut _cef_display_handler_t {
+		self.object.cast()
+	}
+}
+
+impl Clone for DisplayHandlerImpl {
+	fn clone(&self) -> Self {
+		unsafe {
+			let rc_impl = &mut *self.object;
+			rc_impl.interface.add_ref();
+		}
+		Self { object: self.object }
+	}
+}
+impl Rc for DisplayHandlerImpl {
+	fn as_base(&self) -> &cef_base_ref_counted_t {
+		unsafe {
+			let base = &*self.object;
+			std::mem::transmute(&base.cef_object)
+		}
+	}
+}
+impl WrapDisplayHandler for DisplayHandlerImpl {
+	fn wrap_rc(&mut self, object: *mut RcImpl<_cef_display_handler_t, Self>) {
+		self.object = object;
+	}
+}
diff --git a/desktop/src/main.rs b/desktop/src/main.rs
index 16190d0f7..fbe8c362b 100644
--- a/desktop/src/main.rs
+++ b/desktop/src/main.rs
@@ -27,7 +27,7 @@ fn main() {
 		// We are in a CEF subprocess
 		// This will block until the CEF subprocess quits
 		let error = cef_context_builder.execute_sub_process();
-		tracing::error!("Cef subprocess failed with error: {error}");
+		tracing::warn!("Cef subprocess failed with error: {error}");
 		return;
 	}