Python and Web Development: Building a Basic Blog with Flask

Introduction
Prerequisites
Setup
Creating the Flask Application
Defining Routes and Views
Creating Templates
Adding a Database
Creating Models
Creating Forms
Adding User Authentication
Conclusion

Introduction

In this tutorial, we will learn how to build a basic blog using Flask, a popular web development framework in Python. Flask allows us to create web applications quickly and easily. By the end of this tutorial, you will have a functional blog application with routes, views, templates, and a backend database.

Prerequisites

Before starting this tutorial, you should have:

Basic knowledge of Python programming language
Basic understanding of HTML and CSS
Python installed on your machine

Setup

To begin, let’s set up our development environment by following these steps:

Open your terminal or command prompt.
Create a new directory for your project.
Navigate to the project directory using cd command.

Once you have set up your development environment, we can proceed with creating the Flask application.

Creating the Flask Application

Flask is a lightweight web framework that allows us to create web applications. In this section, we will create a basic Flask application.

Open your favorite text editor or IDE.
Create a new Python file called app.py.
Import the Flask module at the beginning of the file:
```
 from flask import Flask, render_template
```
Initialize the Flask application:
```
 app = Flask(__name__)
```

Define a route and a view function for the home page:

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

Add the following code at the end of the file:
```
 if __name__ == '__main__':
     app.run(debug=True)
```
Now, when we run the Flask application, it will display the home page template. But before we proceed, we need to create the templates folder and the home.html file inside it.

Creating Templates

Templates allow us to separate the presentation logic from the application logic. In this step, we will create the home.html template file.

Create a new folder called templates in your project directory.
Inside the templates folder, create a new file called home.html.

Add the following code to the home.html file:

 <!DOCTYPE html>
 <html>
   <head>
     <title>My Blog</title>
   </head>
   <body>
     <h1>Welcome to My Blog</h1>
   </body>
 </html>

Now that we have our basic Flask application and template in place, let’s move on to adding a database.

Adding a Database

A blog typically requires storing and retrieving data, such as blog posts and user information. In this step, we will add a database to our Flask application using Flask-SQLAlchemy.

Install the flask_sqlalchemy package by running the following command in your terminal:
```
 pip install flask_sqlalchemy
```

Import the SQLAlchemy module in the app.py file:

 from flask_sqlalchemy import SQLAlchemy

Set up the database configuration:

 app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///blog.db'
 db = SQLAlchemy(app)

Create a new file called models.py in your project directory.

Import the db object from app.py and create the Post model class in models.py:

 from app import db
	
 class Post(db.Model):
     id = db.Column(db.Integer, primary_key=True)
     title = db.Column(db.String(100), nullable=False)
     content = db.Column(db.Text, nullable=False)

Now we have a database set up and a Post model defined. Let’s move on to creating forms.

Creating Forms

Forms are an essential part of any blog application. In this section, we will create a form to allow users to submit new blog posts.

Install the flask_wtf package by running the following command in your terminal:
```
 pip install flask_wtf
```
Import the FlaskForm class from flask_wtf and the StringField, SubmitField, and TextAreaField classes from wtforms in app.py:
```
 from flask_wtf import FlaskForm
 from wtforms import StringField, SubmitField, TextAreaField
```
Create a new file called forms.py in your project directory.

Define the PostForm class inside forms.py:

 from flask_wtf import FlaskForm
 from wtforms import StringField, SubmitField, TextAreaField
 from wtforms.validators import DataRequired
	
 class PostForm(FlaskForm):
     title = StringField('Title', validators=[DataRequired()])
     content = TextAreaField('Content', validators=[DataRequired()])
     submit = SubmitField('Submit')

With our form defined, we can move on to adding user authentication.

Adding User Authentication

User authentication is crucial for any blog application. In this section, we will implement user authentication using Flask-Login.

Install the flask_login package by running the following command in your terminal:
```
 pip install flask_login
```
Import the LoginManager class from flask_login in app.py:
```
 from flask_login import LoginManager
```
Set up the login manager configuration:
```
 login_manager = LoginManager(app)
```
Create a new file called models.py in your project directory if it doesn’t exist already.

Import the UserMixin class from flask_login and update the Post model class in models.py:

 from app import db
 from flask_login import UserMixin
	
 class User(UserMixin, db.Model):
     id = db.Column(db.Integer, primary_key=True)
     username = db.Column(db.String(100), nullable=False)
     password = db.Column(db.String(100), nullable=False)
	
 class Post(db.Model):
     id = db.Column(db.Integer, primary_key=True)
     title = db.Column(db.String(100), nullable=False)
     content = db.Column(db.Text, nullable=False)
     user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)

Now we have implemented user authentication using Flask-Login.

Conclusion

In this tutorial, we have learned how to build a basic blog using Flask. We started by setting up the Flask application and creating templates. Then, we added a database using Flask-SQLAlchemy, created forms using Flask-WTF, and implemented user authentication using Flask-Login.

By following this tutorial, you have gained a fundamental understanding of Flask and its capabilities. You can further enhance your blog by adding more features, such as post editing, user registration, and comment functionality.

Remember to explore the Flask documentation and experiment with different functionalities to expand your knowledge of web development with Python.

I hope you find this tutorial helpful! If you have any questions or encounter any issues, feel free to leave a comment below. Happy coding!

Published: 18 January 2023