"Building a Web Application with Flask: A Step-by-Step Guide"

 "Building a Web Application with Flask: A Step-by-Step Guide"

Flask is a popular web framework for building web applications in Python. In this article, we will walk through the process of building a simple web application using Flask. We will cover how to set up the application, create routes, handle user input, and display data.

Step 1: Set up the Flask Application

To get started, we will create a new Python file and import Flask. We will then create a new Flask application instance and run it.

python

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from flask import Flask

app = Flask(__name__)

@app.route('/')

def home():

return 'Hello, World!'

if __name__ == '__main__':

app.run()

In this code, we create a new Flask application instance and define a route for the home page ('/'). The home() function returns a simple greeting. We then start the Flask application using the run() method.

Step 2: Create Routes

Next, we will create more routes for our web application. We will create routes for a login page and a dashboard page.

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@app.route('/login')

def login():

return 'Please enter your credentials'

@app.route('/dashboard')

def dashboard():

return 'Welcome to your dashboard'

In this code, we create two new routes for the login page ('/login') and the dashboard page ('/dashboard'). The login() function returns a message asking the user to enter their credentials, and the dashboard() function returns a welcome message.

Step 3: Handle User Input

Now that we have created some routes, we can handle user input. We will create a route for a search page and a form to allow the user to search for information.

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from flask import request

@app.route('/search', methods=['GET', 'POST'])

def search():

if request.method == 'POST':

search_term = request.form['search']

return f'Search results for: {search_term}'

else:

return '''

<form method="post">

<label for="search">Search:</label>

<input type="text" name="search" id="search">

<button type="submit">Search</button>

</form>

'''

In this code, we create a new route for the search page ('/search') that accepts both GET and POST requests. If the request method is POST, we retrieve the search term from the form and return the search results. If the request method is GET, we display a form to allow the user to enter their search term.

Step 4: Display Data

Finally, we can display data on our web application. We will create a route to display a list of items and a route to display details about a specific item.

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@app.route('/items')

def items():

item_list = ['Item 1', 'Item 2', 'Item 3']

return '<br>'.join(item_list)

@app.route('/item/<id>')

def item(id):

return f'Details for Item {id}'

In this code, we create a new route for the items page ('/items') that displays a list of items. We also create a new route for the item details page ('/item/<id>') that accepts an item ID as a parameter and displays details for that item.

Conclusion

In this article, we have walked through the process of building a simple web application using Flask. We have covered how to set up the application, create routes, handle user input, and display data. Flask is a powerful web framework that can be used to build a wide range of web applications, and we hope this guide has provided a useful introduction to Flask web development.