inspector: use js_app.html as the landing page for chrome devtools

As of this commit in chromium -
https://chromium-review.googlesource.com/c/chromium/src/+/905450
a new landing page (js_app.html) has been added and inspector.html
has been made as the fallback page.

Another motivation for this patch is the following bug in
chromium -
https://bugs.chromium.org/p/chromium/issues/detail?id=846642
due to which, source maps won't get applied with inspector.html,
but works with js_app.html

In order to maintain compatibility, this patch adds a URL
"devtoolsFrontendUrlCompat" to the response of /json/list REST API
so that those using Chrome browsers older than 66.0.3345.0
could use this to open DevTools.

PR-URL: https://github.com/nodejs/node/pull/21385
Refs: https://bugs.chromium.org/p/chromium/issues/detail?id=846642
Refs: https://chromium-review.googlesource.com/c/chromium/src/+/905450
Reviewed-By: Aleksei Koziatinskii <ak239spb@gmail.com>
Reviewed-By: Jan Krems <jan.krems@gmail.com>
Reviewed-By: Matheus Marchini <matheus@sthima.com>

2 files changed, 18 insertions, 5 deletions

diff --git a/src/inspector_socket_server.cc b/src/inspector_socket_server.cc
index d5eb1b75c8..174dc7c726 100644
--- a/src/inspector_socket_server.cc
+++ b/src/inspector_socket_server.cc
@@ -334,16 +334,27 @@ void InspectorSocketServer::SendListResponse(InspectorSocket* socket,
       detected_host = FormatHostPort(socket->GetHost(),
                                      session->server_port());
     }
-    std::ostringstream frontend_url;
-    frontend_url << "chrome-devtools://devtools/bundled";
-    frontend_url << "/inspector.html?experiments=true&v8only=true&ws=";
-    frontend_url << FormatAddress(detected_host, id, false);
-    target_map["devtoolsFrontendUrl"] += frontend_url.str();
+    std::string formatted_address = FormatAddress(detected_host, id, false);
+    target_map["devtoolsFrontendUrl"] = GetFrontendURL(false,
+                                                       formatted_address);
+    // The compat URL is for Chrome browsers older than 66.0.3345.0
+    target_map["devtoolsFrontendUrlCompat"] = GetFrontendURL(true,
+                                                             formatted_address);
     target_map["webSocketDebuggerUrl"] = FormatAddress(detected_host, id, true);
   }
   SendHttpResponse(socket, MapsToString(response));
 }
 
+std::string InspectorSocketServer::GetFrontendURL(bool is_compat,
+    const std::string &formatted_address) {
+  std::ostringstream frontend_url;
+  frontend_url << "chrome-devtools://devtools/bundled/";
+  frontend_url << (is_compat ? "inspector" : "js_app");
+  frontend_url << ".html?experiments=true&v8only=true&ws=";
+  frontend_url << formatted_address;
+  return frontend_url.str();
+}
+
 bool InspectorSocketServer::Start() {
   CHECK_NE(delegate_, nullptr);
   CHECK_EQ(state_, ServerState::kNew);
diff --git a/src/inspector_socket_server.h b/src/inspector_socket_server.h
index b8d98e13a2..bbc2195095 100644
--- a/src/inspector_socket_server.h
+++ b/src/inspector_socket_server.h
@@ -81,6 +81,8 @@ class InspectorSocketServer {
 
   void SendListResponse(InspectorSocket* socket, const std::string& host,
                         SocketSession* session);
+  std::string GetFrontendURL(bool is_compat,
+                             const std::string &formatted_address);
   bool TargetExists(const std::string& id);
 
   enum class ServerState {kNew, kRunning, kStopping, kStopped};