The underlying protocol data in CDP is sent with an error when the type is MethodDestination::Target.

[ImmortalD]

I compared the data sent by chromedp at the underlying level and found that there is an error in the handling by handless-chrome when the type is MethodDestination::Target. The data comparison is as follows.

chromedp data:

-> {"id":3,"sessionId":"1BA8CA430D6B3C717038B13FCB3808BE","method":"Runtime.enable"}
-> {"id":4,"sessionId":"1BA8CA430D6B3C717038B13FCB3808BE","method":"Runtime.evaluate","params":{"expression":"self"}}
-> {"id":5,"sessionId":"1BA8CA430D6B3C717038B13FCB3808BE","method":"Log.enable"}
-> {"id":6,"sessionId":"1BA8CA430D6B3C717038B13FCB3808BE","method":"Network.enable","params":{}}
-> {"id":7,"sessionId":"1BA8CA430D6B3C717038B13FCB3808BE","method":"Inspector.enable"}
-> {"id":8,"sessionId":"1BA8CA430D6B3C717038B13FCB3808BE","method":"Page.enable"}
-> {"id":9,"sessionId":"1BA8CA430D6B3C717038B13FCB3808BE","method":"DOM.enable","params":{}}
-> {"id":10,"sessionId":"1BA8CA430D6B3C717038B13FCB3808BE","method":"CSS.enable"}
-> {"id":11,"sessionId":"1BA8CA430D6B3C717038B13FCB3808BE","method":"Target.setDiscoverTargets","params":{"discover":true}}
-> {"id":12,"sessionId":"1BA8CA430D6B3C717038B13FCB3808BE","method":"Target.setAutoAttach","params":{"autoAttach":true,"waitForDebuggerOnStart":false,"flatten":true}}
-> {"id":13,"sessionId":"1BA8CA430D6B3C717038B13FCB3808BE","method":"Page.setLifecycleEventsEnabled","params":{"enabled":true}}
-> {"id":14,"sessionId":"1BA8CA430D6B3C717038B13FCB3808BE","method":"Fetch.enable","params":{"patterns":[{"urlPattern":"*.js"}]}}
-> {"id":15,"sessionId":"1BA8CA430D6B3C717038B13FCB3808BE","method":"Network.setBypassServiceWorker","params":{"bypass":true}}
-> {"id":16,"sessionId":"1BA8CA430D6B3C717038B13FCB3808BE","method":"Page.navigate","params":{"url":"https://github.com"}}

modify headless-chrome code:
https://github.com/rust-headless-chrome/rust-headless-chrome/blob/main/src/browser/transport/mod.rs#L140-L156

        match destination {
            MethodDestination::Target(session_id) => {
                println!("--> {}", message_text);    // modify here !  add log
                let message = message_text.clone();
                let target_method = Target::SendMessageToTarget {
                    target_id: None,
                    session_id: Some(session_id.0),
                    message,
                };
                trace!(
                    "Msg to tab: {}",
                    message_text.chars().take(300).collect::<String>()
                );
                if let Err(e) = self.call_method_on_browser(target_method) {
                    warn!("Failed to call method on browser: {:?}", e);
                    self.waiting_call_registry.unregister_call(call.id);
                    trace!("Unregistered callback: {:?}", call.id);
                    return Err(e);
                }
            }

            MethodDestination::Browser => {
                println!("-> {}", message_text);   // modify here !  add log
                if let Err(e) = self.web_socket_connection.send_message(&message_text) {
                    self.waiting_call_registry.unregister_call(call.id);
                    return Err(e);
                }
                trace!("sent method call to browser via websocket");
            }
        }

handless-chrome data:

-> {"method":"Target.setDiscoverTargets","id":0,"params":{"discover":true}}
-> {"method":"Target.createTarget","id":1,"params":{"url":"about:blank"}}
-> {"method":"Target.attachToTarget","id":2,"params":{"targetId":"FB9F6999A5BEC7F7FE04DAAB609996F5"}}
--> {"method":"Page.enable","id":3,"params":null}
-> {"method":"Target.sendMessageToTarget","id":4,"params":{"message":"{\"method\":\"Page.enable\",\"id\":3,\"params\":null}","sessionId":"E42FB4211052EAB4B0D1E8CEE726C87D"}}
--> {"method":"Page.setLifecycleEventsEnabled","id":5,"params":{"enabled":true}}
-> {"method":"Target.sendMessageToTarget","id":6,"params":{"message":"{\"method\":\"Page.setLifecycleEventsEnabled\",\"id\":5,\"params\":{\"enabled\":true}}","sessionId":"E42FB4211052EAB4B0D1E8CEE726C87D"}}
--> {"method":"DOM.enable","id":7,"params":null}
-> {"method":"Target.sendMessageToTarget","id":8,"params":{"message":"{\"method\":\"DOM.enable\",\"id\":7,\"params\":null}","sessionId":"E42FB4211052EAB4B0D1E8CEE726C87D"}}
--> {"method":"CSS.enable","id":9,"params":null}
-> {"method":"Target.sendMessageToTarget","id":10,"params":{"message":"{\"method\":\"CSS.enable\",\"id\":9,\"params\":null}","sessionId":"E42FB4211052EAB4B0D1E8CEE726C87D"}}
-> {"method":"Target.createTarget","id":11,"params":{"url":"about:blank","width":1024,"height":800}}
-> {"method":"Target.attachToTarget","id":12,"params":{"targetId":"6A1E1A0D64290919A3E0CE57CFE0B648"}}
--> {"method":"Page.enable","id":13,"params":null}
-> {"method":"Target.sendMessageToTarget","id":14,"params":{"message":"{\"method\":\"Page.enable\",\"id\":13,\"params\":null}","sessionId":"F4A5DF92E336C6BB45F3B85AC79EFB07"}}
--> {"method":"Page.setLifecycleEventsEnabled","id":15,"params":{"enabled":true}}
-> {"method":"Target.sendMessageToTarget","id":16,"params":{"message":"{\"method\":\"Page.setLifecycleEventsEnabled\",\"id\":15,\"params\":{\"enabled\":true}}","sessionId":"F4A5DF92E336C6BB45F3B85AC79EFB07"}}
--> {"method":"Log.enable","id":17,"params":null}
-> {"method":"Target.sendMessageToTarget","id":18,"params":{"message":"{\"method\":\"Log.enable\",\"id\":17,\"params\":null}","sessionId":"F4A5DF92E336C6BB45F3B85AC79EFB07"}}
--> {"method":"Fetch.enable","id":19,"params":{"patterns":[{"urlPattern":"*9898.a45c487b.js","resourceType":"Script","requestStage":"Request"}],"handleAuthRequests":true}}
-> {"method":"Target.sendMessageToTarget","id":20,"params":{"message":"{\"method\":\"Fetch.enable\",\"id\":19,\"params\":{\"patterns\":[{\"urlPattern\":\"*.js\",\"resourceType\":\"Script\",\"requestStage\":\"Request\"}],\"handleAuthRequests\":true}}","sessionId":"F4A5DF92E336C6BB45F3B85AC79EFB07"}}
--> {"method":"Network.setBypassServiceWorker","id":21,"params":{"bypass":true}}
-> {"method":"Target.sendMessageToTarget","id":22,"params":{"message":"{\"method\":\"Network.setBypassServiceWorker\",\"id\":21,\"params\":{\"bypass\":true}}","sessionId":"F4A5DF92E336C6BB45F3B85AC79EFB07"}}

When comparing the last two lines of headless-chrome with the last line of chromedp, it is clear that headless-chrome only needs to add the sessionId field, while in reality, the JSON data is wrapped with an additional layer. causing some function calls to be ineffective ， eg: #429