How to use the flask module for web development in Python 2.x

How to use the Flask module for Web development in Python 2.x

Introduction:
With the rapid development of the Internet, Web development has become a very important technology in the Internet industry. In Python web development, the Flask framework is a very popular choice. It is simple, lightweight, flexible and easy to use, and is suitable for the rapid development of small and medium-sized projects. This article will introduce how to use the Flask module for web development in Python 2.x version, and give corresponding code examples.

Install Flask:
Before we start, we need to install the Flask module. You can use the pip command to install it. The specific command is as follows:

pip install flask

Create a Flask application:
After installing the Flask module, we can create a simple Flask application. The following code demonstrates the simplest Flask application:

from flask import Flask

app = Flask(__name__)

@app.route('/')
def index():
    return 'Hello, Flask!'

if __name__ == '__main__':
    app.run(debug=True)

In the above code, we first import the Flask module and create a Flask application instance. Next, we use the @app.route('/') decorator to specify a URL route. When the user accesses the root path in the browser, index()## will be called. # Function and return the corresponding string. Finally, we use the app.run() method to run the application.

Run the application:

After completing the steps to create a Flask application, we can run the application and view the results in the browser. Just run the Python script file where the above code is located and visit http://localhost:5000 to see the 'Hello, Flask!' string.

Response to different URLs:

The Flask framework can easily respond to different URL requests. The following sample code demonstrates how to respond to different URL requests:

@app.route('/')
def index():
    return 'Hello, Flask!'

@app.route('/about')
def about():
    return 'This is about page'

@app.route('/contact')
def contact():
    return 'Please contact us at info@example.com'

In the above code, we defined three functions: index(), about() and contact() respectively, and used different URL paths. as a decorator parameter. When the user accesses different URLs, the corresponding function will be called and the corresponding string will be returned.

Passing parameters:

The Flask framework also supports passing parameters. The following sample code demonstrates how to pass parameters and operate with parameter values:

@app.route('/user/<name>')
def user(name):
    return 'Hello, {}'.format(name)

In the above code, we define a function named user() and use

Parameters as part of the decorator. When a user accesses a URL path like /user/xxx, xxx will be passed as a parameter value to the user() function.

Templates and static files:

In actual web development, we usually need to use templates to render dynamic content and provide static files (such as CSS, JavaScript, images, etc.). The Flask framework also provides corresponding support. The following sample code demonstrates how to use templates and serve static files:

from flask import Flask, render_template

app = Flask(__name__)

@app.route('/')
def index():
    return render_template('index.html')

if __name__ == '__main__':
    app.run(debug=True)

In the above code, we first imported the

render_template function and created a file named index.html template file. In the index() function, we use the render_template() function to render the index.html template and return the rendered result.

Summary:

This article introduces how to use the Flask module for web development in Python 2.x version. By installing the Flask module, creating an application, responding to different URL requests, passing parameters, and using templates and serving static files, we can start simple and fast web development. Hope this article helps you!

Reference link:

Flask official documentation: http://flask.pocoo.org/
• Flask source code repository: https://github.com/ pallets/flask

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