node --inspect: dev tools console not working

[atif089]

Version: 6.9.1 and 7.0
Platform: Windows 7 x64 (Chrome 54.0.2840.71 m)
Subsystem:

• Create a file test.js with console.log("Hello World");
• Run node --inspect --debug-brk test.js

On the console tab, I don't see any input field. When I press escape and open the smaller console tab, I have suggest for input, but I can't execute code.

The latter works when I change the URL query param from ws=localhost:9229/node to ws=127.0.0.1:9229/node

I made a small video to display the problem that I have been facing.

• https://www.youtube.com/watch?v=YIoA_SP3ObA

[eugeneo]

This is not a Node.js bug but a Chrome DevTools issue.

[atif089]

@eugeneo Shall I post it at bugs.chromium.org ?

[eugeneo]

Yes, please. Can you also try Node 7 - either nightly build or build from the sources? It uses newer devtools, the bug might not be reproducible there.

[atif089]

Sure, I can try from the nightly build it in an hour and will post my results here. I'm a meagre front end developer so I might not be able to build it myself from the sources.

[atif089]

@eugeneo Yep! The console is working fine in the v8.0.0-nightly201610310e92bb99c6 release. I can see the blue arrow and the input box.

But one original problem which was also there in the previous issue still remains which is that I need to replace localhost with 127.0.0.1 otherwise the console would not print statement.

For example the URL

chrome-devtools://devtools/bundled/inspector.html?experiments=true&v8only=true&ws=localhost:9229/0bd7
6823-b73d-4b59-b4c0-aac52bbbb0a5`

Becomes

chrome-devtools://devtools/bundled/inspector.html?experiments=true&v8only=true&ws=127.0.0.1:9229/0bd7
6823-b73d-4b59-b4c0-aac52bbbb0a5`

[eugeneo]

This sounds like something odd in Windows networking - so it has to be looked into.

[atif089]

I tried digging around a bit more on this issue. I'm using this plugin called Inspect Process.

It tries to read the debugger URL and launch debug tools in a new process (Source). I was expecting the console to work when I replaced localhost with 127.0.0.1 and launch the process. But it still doesn't work and I face the same problem.

The only way I could see this working is when I manually open Chrome and then paste the debug URL replacing localhost with 127.0.0.1.

I now feel maybe there is something wrong with my Windows itself or my copy of Chrome so today I will create a fresh Windows 7 VM and then try it inside the VM and report it here.

[atif089]

@eugeneo tried it inside a new Windows VM

• Windows 7 x86
• Node v7.0.0

everything worked perfectly fine for the first time. And then from the second time onwards the same problem reflects, i.e using 127.0.0.1 instead of localhost

[eugeneo]

Looks like some Windows7 setups are not able to resolve localhost. This can either be addressed with changing the Windows setup or by using 127.0.0.1 as a host name.

[atif089]

@eugeneo Thanks for pushing the localhost -> 127.0.0.1 change. Do you know when does it normally get merged into the nightly build?

Also, one last question about localhost not resolving on Windows 7 setups. Did you mean the resolution is setting up the line 127.0.0.1 localhost inside the system32/drivers/etc/hosts file? Because that doesn't work either.

However localhost in the browser points to the webserver if it's running.

[eugeneo]

@atif089 I have never being able to reproduce this problem as it seems like some pecularity with Windows7 setups and/or specific network environments. Some browsers might be using different resolution facilities so the results may differ ever so slightly.

Right now I need to wait 48 hours before actually submitting this patch (there might be some issues that I have not thought about so I would like other Node contributors take a look). So it should be in by the Tuesday build.

[atif089]

@eugeneo Weird part is that I use this plugin called inspect-process which uses chrome driver and only launches an instance of DevTools.

I changed it's source to replace localhost with 127.0.0.1 so that it looks like this

proc.stderr.on('data', (data) => {
      let dataStr = data.toString();
      const isListening = dataStr.startsWith('Debugger listening on port');
      const isAttached = dataStr.startsWith('Debugger attached');
      const isComplete = dataStr.startsWith('Waiting for the debugger to disconnect');

      if (isListening) {
        dataStr = dataStr.replace("localhost", "127.0.0.1");
        return devtools.open(dataStr.substring(dataStr.indexOf('chrome-devtools')));

      } else if (isComplete) {

The problem still exists.

But if I manually open Google Chrome and then paste that link with 127.0.0.1, it works.

Video -> https://www.youtube.com/watch?v=0mll_sCzSAI

I posted this because maybe it might not work even after your last commit due to this problem.

[atif089]

Quickly tested on a Windows 8 and Windows 10 VM. And it exists there too. I also see this error in console

[2744:7908:1104/003631:ERROR:CONSOLE(1)] "Uncaught ReferenceError: DevToolsAPI is not defined", source:  (1)
[2744:7908:1104/003631:ERROR:CONSOLE(4461)] "Request Log.enable failed. {"code":-32601,"message":"'Log.enable' wasn't found"}", source: chrome-devtools://devtoo
ls/bundled/inspector.js (4461)

[atif089]

Hi @eugeneo,

I tried using Visual Studio Code's debugger last weekend and it seems to work without any problem. Does it work differently than the Chrome's debug tools?

[eugeneo]

Probably they are not using "localhost" - just the IP address.

On Mon, Nov 7, 2016 at 2:55 AM Mohammed Ameenuddin Atif <
[email protected]> wrote:

Hi @eugeneo https://github.com/eugeneo,

I tried using Visual Studio Code's debugger last weekend and it seems to
work without any problem. Does it work differently than the Chrome's debug
tools?

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[atif089]

Yep, looks like it.

https://github.com/Microsoft/vscode/search?l=TypeScript&q=%22127.0.0.1%22&type=Code&utf8=%E2%9C%93