How to use Flask in Google Colaboratory Python Notebook?

Question

I am trying to build a website using Flask, in a Google Colab Python notebook. However, running a regular Flask code that works on a regular Python, fails to work on Google

Answer 1

The server side code AKA: backend

from flask import Flask
import threading

app = Flask(__name__)

@app.route("/")
def hello():
    return "Hello World!"

threading.Thread(target=app.run, kwargs={'host':'0.0.0.0','port':6060}).start()

Rendering the server inside the colab

import IPython.display

def display(port, height):
    shell = """
        (async () => {
            const url = await google.colab.kernel.proxyPort(%PORT%, {"cache": true});
            const iframe = document.createElement('iframe');
            iframe.src = url;
            iframe.setAttribute('width', '100%');
            iframe.setAttribute('height', '%HEIGHT%');
            iframe.setAttribute('frameborder', 0);
            document.body.appendChild(iframe);
        })();
    """
    replacements = [
        ("%PORT%", "%d" % port),
        ("%HEIGHT%", "%d" % height),
    ]
    for (k, v) in replacements:
        shell = shell.replace(k, v)

    script = IPython.display.Javascript(shell)
    IPython.display.display(script)

display(6060, 400)