This question corresponds to this QtWebSockets implementation.
I am trying to include websockets server functionality in a bigger qt-based project.
I have cloned the repo above and built the library as well as the example applications (release mode). Among the examples there is an echoserver and an echoclient. After built i start the echoserver, which seems to be successful (on terminal i see: Echoserver listening on port 1234). Then i start the echoclient, which exits immediately (no printout on the console). The server console does not show any signs of detecting connection attempts. The server listens on 0.0.0.0:1234 (checked with netstat). The client tries to connect on "ws://localhost:1234/".
I modified the echoclient example to connect to echo.websocket.org and rebuilt it. After starting the client it connects successfully and the sent message is echoed back.
I created a simple html file with a websocket client trying to connect to the echoserver and opened it with a browser. This again cannot connect to the server (works with echo.websocket.org).
Environment:
Ubuntu 13.10(64bit) running as a virtualbox guest on a win7 machine.
Qt5.2(64bit)
I thought that this is something to do with the virtualbox networking settings, so i repeated the whole thing above on the host OS (win7, 64bit). I get the same results.
Br,
Szabolcs
This problem does not happen in Qt 5.4 anymore. According to the comments above it was a bug in Qt and it seems to be fixed now, because in my environment the echoserver and echoclient work just fine.
My Environment:
Ubuntu 14.04(64bit) running as a virtualbox guest on a win7 machine.
Qt5.4(32bit)
Therefore I propose to mark this question as answered.
Related
** I am not a Linux expert.
I have spun a Debian 10 VM in GCP which i need to access like in a GUI mode and be able to download and install some required applications for development and experiment purposes.
I think i have installed xrdp, display GUI packages, firefox, apache2 etc, but not able to land into GUI mode or browser mode.
1- I can't invoke/run firefox with "Display" error - Error: no DISPLAY environment variable specified
2- RDP from my local laptop also being refused with "connection refused" error.
Need some help.
I am building a .net core 2.0 console app on windows 10 but I want to debug it on a remote linux server running debian 9.
I found this article:
https://blogs.msdn.microsoft.com/devops/2017/01/26/debugging-net-core-on-unix-over-ssh/
but where I get stuck is selecting the SSH connection. My remote server has authentication and if I enter the user#ip:port it doesn't find anything.
I found some mention of using SSH tunnelling but as there is no dotnet process listening on the server (it's installed but it doesn't have any listening service running I can see) I am unsure exactly what port I'm meant to be tunnelling or even which direction to tunnel it.
What do I need to do to get my SSH connection visible in the debugger?
I just tried this and I found that the Find.. button doesn't do anything either.
First you enable SSH connections in your Linux host (in my case, Ubuntu, I had to run sudo ufw allow ssh). Test things out by opening cmd on Windows and doing ssh user#host.
Then, on Visual Studio, in the SSH attach to process window, make sure you hit "refresh" and check the "show processes from all users" box. You should see the "dotnet" process running.
EDIT: you should be prompted for the remote host's password at some point. Here's the dialog shown when I changed the password on the remote host and then attempted to debug.
I've been setting up remote debugging for an embedded Linux target. I've tested that I have the correct combination of gdbserver running on the target and gdb client running on my workstation. I can start the server and on the workstation side run:
(gdb) target remote 10.28.22.226:2345
and I can list source and step just fine.
In Qt Creator I have configured a device. In that window I specify the GDB server executable: gdbserver (see pic).
I also configure the cross debugger in the 'Build & Run' Debuggers tab as shown below:
In this case, I have manually started the gdbserver with my executable on the target with port 2345. To start debugging with Qt Creator, I choose the Debug->Start Debugging->Attach to running Debug server pulldown menu. It gives me the prompt shown below, where I enter the server port (2345). I give it the appropriate kit and local executable (copy of the executable on the remote target).
After I hit OK, it seems to run the gdb client locally with a few commands, then times out trying to communicate with the gdbserver. I have debug logging turned on with the server, so I know the server never sees anything from the client run from Qt Creator. Additionally, I did Window->Views->Debugger Log to help me get a better idea of what was going on. The log shows the correct IP address and port for my device, but I don't see anything that looks like a 'target remote IP:port' call.
I'm looking for a hint or reference here. I seem to be a bit stuck at the moment. Thanks!
EDIT: additional information - I've verified that my gdb client has support for python compiled in. I see that Qt Creator requires python support. I also have further support that nothing ever goes out on the wire from Qt Creator. I did a wireshark capture and don't see anything going to port 2345 on the target.
Alternately, if anyone would share their Qt Creator debugger-log output with me so I can compare, that would be helpful.
Avoid Qt Creator 4.5-beta1. It seems 4.5RC1 doesn't have this problem. I was able to do remote debugging using the method described above just fine.
Even QtCreator 4.5.0 seems to have the same bug.
The only workaround I've found is to start the GDB server manually on the remote target: with "top" I get the pid of the remote process to debug then I run the following command: gdbserver --attach remote ip:remote port pid.
After the server is listening, I finally choose: "Attach to Running Debug" server".
Maybe you can write a server start script on target which include the above statement...
I have to set a development environment on a ubuntu machine(16.04).
It's django+postgresql+Nginx, I.think I could install all these things together on that machine，but I totally don't have any idea about how to connect it by using pycharm running on my pc, and how to manipulate the database.
Is there anyone could tell me how to connect it. This is the first time I have to use a remote machine.
By the way, my pc and ubuntu machine are in the same LAN, but there is another person who were asked to write db are not.
I hope I could get some suggestions from the community.
One of the best and common way is to use SSH.
Here you can find an official guide on how to enable SSH server on Ubuntu 16.04
You can use Putty to connect from Windows PC to your SSH server or if you're using Mac or Linux, there should be already installed SSH client. So, just ssh username#servername
Use SSH. Assuming you're on Linux, open a terminal and type:
ssh username#local-ip-address-of-machine
and then type your password when prompted. Your terminal window essentially acts as a terminal on your remote machine. From here, I suggest you research Docker in order to set up a custom environment for your Django project. I have only told you how to connect since that's your question, and there are plenty of tutorials on setting up Django and Docker. If the other person wants to connect, you will need to port forward on your router port 22 on the local IP of the machine.
If you haven't got SSH set up, this page tells you how.
Does anyone know if it is possible to run python-gui apps, like wxPython, on a c9.io remote server? I have my home server set up with c9 via SSH, and no issues logging in and running apps in the terminal on the VM. However, when I try to run GUI apps, I get the following error message.
Unable to access the X Display, is $DISPLAY set properly?
After searching and searching, I can't seem to find a guide or anything in the docs that detail how to set $DISPLAY in the script. X display is installed and active on my server, but I don't know how to configure the c9 script to access it properly. Any assistance would be appreciated!
I don't know if Cloud9 supports it but normally to run a remote GUI application you would have ssh forward the X11 communication over the ssh connection via a tunnel. So basically the application is running on the remote system and it is communicating with a local X11 server which provides you with the display and handling of the mouse and keyboard.
If you run ssh with the -X parameter then it will attempt to set up the X11 tunnel and set $DISPLAY in the remote shell so any GUI applications you run there will know how to connect to the X11 tunnel. Bw aware however that this is something that can be turned off on the remote end, so ultimately it is up to Cloud9 whether they will allow you to do this.