Check out example codes for "https://cloud.google.com/shell/docs/using-web-preview#previewing_the_application". It will help you in understanding the concepts better.

Code Example 1

cd `mktemp -d` \
    && echo '<html><body>Hello World</body></html>' >./index.html \
    && python -m SimpleHTTPServer 8080

Code Example 2

git clone https://github.com/GoogleCloudPlatform/appengine-guestbook-python \
    && cd appengine-guestbook-python \
    && dev_appserver.py ./app.yaml

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