Chrome extension: can devtools panel receive one-time messages?

Question

In my code for devtool.js I am listening to one-time messages like this:

chrome.devtools.panels.create("TT's Automatron", "devtool/icon.ico", "devtool/panel.html",
  function(panel) {

    var panelconsole; 

    panel.onShown.addListener(function tmp(panel) {

        panel.onShown.removeListener(tmp); 
        panelconsole = panel;

        // this works
        chrome.runtime.sendMessage({type:'get-status'}, function(response) {
          panelconsole.write_queue(response.globalstatus);
        });;

        // this does not work - cannot listen to the same messages from popup.js 
        // as I do it in background.js
        chrome.runtime.onMessage.addListener(function(request, sender, sendResponse) {    
          alert();
        });    
    });    
  }
);

In the code I can send one-time message but cannot listen to one-time messages. Alert() is never triggered, even if messages are sent. In background script I can listen to the messages without problems by chrome.runtime.onMessage.addListener(), so why not in devtools?

I was reading documentation but there is not a receiving of one-time message shown, only session connection. Does it mean it is not possible?

---

In background script I am listening to the same messages and there it works:

// listening to the same messages as in devtools panel
chrome.runtime.onMessage.addListener(function(request, sender, sendResponse) {

  alert('This works');

  switch(request.type) {

    // recognising different messages
    case "start-tron":    
      //  ..some code..       
      sendResponse({globalstatus: globalstatus});

      break;
   }
});

---

The messages are coming from popup script:

chrome.tabs.query({active: true, currentWindow: true}, function(tabs) {
  chrome.runtime.sendMessage({type: "start-tron", tabid:tabs[0].id});
});

---

Maybe I should mention that there is also an open long-lived session connection between background and devtools:

var port = chrome.runtime.connect({name: 'automatron_console'});
port.onMessage.addListener(function(item) {
    // if reference exists - panel is open
    if (panelconsole) {
      panelconsole.write_log(item);
    }
});

---

So why can't I listen to the messages from popup in devtools.js as I do it in background.js?

Answer 1

In documentation is not directly noted, that it is not possible to receive one-time messages in a devtools panel, however there is only long-lived connection mentioned so I suppose that one-time messaging is not supported for devtools.

It seems that sending one-time messages is possible, as shown in the script above, but not receiving.

We can only use long-lived connection:

// creating communication port in devtool script
var devtools_connection = chrome.runtime.connect({name: 'devtools_connection'});

// listening to the port messages
devtools_connection.onMessage.addListener(function(request, sender, sendResponse) {
  // sending response back to what sent this message
  sendResponse('some response');
});

// sending messages to the port
devtools_connection.postMessage({msg: 'some message'});