Code Bug in server.py in 3Dmol Source Code

Q

Why am I getting the "Connection refused" error when accessing my local 3Dmol Viewer?

✍: FYIcenter.com

A

If you are getting the "Connection refused" error when accessing your hosted 3Dmol Viewer over the network, it's most likely caused by the code bug in the server's Python source code.

1. Make sure that your 3Dmol Viewer is running:

fyicenter$ curl http://localhost:5000

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<title>Redirecting...</title>
<h1>Redirecting...</h1>
<p>You should be redirected automatically to target URL: 
  <a href="/static/viewer.html">static/viewer.html</a>

2. Make sure the firewall is open for port 5000:

fyicenter$ sudo firewall-cmd --zone=public --add-port=5000/tcp
fyicenter$ sudo firewall-cmd --runtime-to-permanent
fyicenter$ sudo firewall-cmd --zone=public --list-all

  public (active)
    target: default
    icmp-block-inversion: no
    interfaces: eno1
    sources: 
    services: cockpit dhcpv6-client http mountd nfs rpc-bind ssh
    ports: 5000/tcp
    protocols: 
    ...

3. Try to connect from a remote computer

fyicenter$ curl http://192.168.1.10:5000

curl: (7) Failed to connect to 192.168.1.10 port 5000: Connection refused

4. Check the server Python source code. You see server is listening only to the default IP address of 127.0.0.1.

fyicenter$ tail server.py 

...
if __title__ == '__main__':
  parser = argparse.ArgumentParser(description='Run 3Dmol.js learning environment server.')
  parser.add_argument('-p','--port', type=int, default=5000, help='Port to run on (default 5000)')
  args = parser.parse_args()
  socketio.run(app,port=args.port)

5. Update the server source code to listen on all IP addresses:

fyicenter$ vi server.py 

...
if __title__ == '__main__':
  parser = argparse.ArgumentParser(description='Run 3Dmol.js learning environment server.')
  parser.add_argument('-p','--port', type=int, default=5000, help='Port to run on (default 5000)')
  args = parser.parse_args()
  socketio.run(app,host='0.0.0.0',port=args.port)

5. Update the server source code to listen on all IP addresses:

fyicenter$ kill %1
fyicenter$ python3 server.py &

[1] 23051

6. Try again from a remote computer

fyicenter$ curl http://192.168.1.10:5000

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
...

Your Online 3Dmol Viewer is ready to accept remote connections.

 

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2023-02-19, 241🔥, 0💬