html_url,issue_url,id,node_id,user,user_label,created_at,updated_at,author_association,body,reactions,issue,issue_label,performed_via_github_app
https://github.com/simonw/datasette/issues/394#issuecomment-642522285,https://api.github.com/repos/simonw/datasette/issues/394,642522285,MDEyOklzc3VlQ29tbWVudDY0MjUyMjI4NQ==,58298410,LVerneyPEReN,2020-06-11T09:15:19Z,2020-06-11T09:15:19Z,NONE,"Hi @wragge,

This looks great, thanks for the share! I refactored it into a self-contained function, binding on a random available TCP port (multi-user context). I am using subprocess API directly since the `%run` magic was leaving defunct process behind :/

![image](https://user-images.githubusercontent.com/58298410/84367566-b5d0d500-abd4-11ea-96e2-f5c05a28e506.png)

```python
import socket

from signal import SIGINT
from subprocess import Popen, PIPE

from IPython.display import display, HTML
from notebook.notebookapp import list_running_servers


def get_free_tcp_port():
    """"""
    Get a free TCP port.
    """"""
    tcp = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    tcp.bind(('', 0))
    _, port = tcp.getsockname()
    tcp.close()
    return port


def datasette(database):
    """"""
    Run datasette on an SQLite database.
    """"""
    # Get current running servers
    servers = list_running_servers()

    # Get the current base url
    base_url = next(servers)['base_url']

    # Get a free port
    port = get_free_tcp_port()

    # Create a base url for Datasette suing the proxy path
    proxy_url = f'{base_url}proxy/absolute/{port}/'

    # Display a link to Datasette
    display(HTML(f'<p><a href=""{proxy_url}"">View Datasette</a> (Click on the stop button to close the Datasette server)</p>'))

    # Launch Datasette
    with Popen(
        [
            'python', '-m', 'datasette', '--',
            database,
            '--port', str(port),
            '--config', f'base_url:{proxy_url}'
        ],
        stdout=PIPE,
        stderr=PIPE,
        bufsize=1,
        universal_newlines=True
    ) as p:
        print(p.stdout.readline(), end='')
        while True:
            try:
                line = p.stderr.readline()
                if not line:
                    break
                print(line, end='')
                exit_code = p.poll()
            except KeyboardInterrupt:
                p.send_signal(SIGINT)
```

Ideally, I'd like some extra magic to notify users when they are leaving the closing the notebook tab and make them terminate the running datasette processes. I'll be looking for it.","{""total_count"": 1, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 1, ""rocket"": 0, ""eyes"": 0}",396212021,base_url configuration setting,