flask start development server
- Import the Flask class from the flask module:
python
from flask import Flask
- Create an instance of the Flask class:
python
app = Flask(__name__)
__name__
is a special variable that is used to determine the root path of the application.Define a route and associated function for the root URL ("/"):
python
@app.route('/')
def hello():
return 'Hello, World!'
The
@app.route('/')
decorator binds the URL '/' to thehello()
function.Run the development server:
python
if __name__ == '__main__':
app.run(debug=True)
- The
if __name__ == '__main__':
block ensures that the development server is only started when the script is executed directly, not when it's imported as a module. app.run(debug=True)
starts the development server with debugging enabled.Save the script and execute it:
bash
python your_script_name.py
Replace
your_script_name.py
with the name of your Python script.Access the development server in a web browser:
http://127.0.0.1:5000/
Open a web browser and enter the specified URL to see the "Hello, World!" message.
Observe the development server console for logs and requests. The
debug=True
parameter enables debugging information.The console will display information about incoming requests and potential issues with the application.
To stop the development server, press
Ctrl+C
in the terminal where it is running.This terminates the server and stops the execution of the Flask application.