专项练习30

**专项练习30: 构建一个简单的博客系统**

在这个专项练习中，我们将构建一个简单的博客系统，包括用户注册、登录、文章发布、评论等功能。我们将使用 Python 和 Flask 框架来实现这个系统。

### 环境准备首先，我们需要安装必要的依赖包：

bashpip install flask flask_sqlalchemy

markdownblog_system/
app.pymodels.pyforms.pytemplates/
base.htmlindex.htmlregister.htmllogin.htmlarticle.htmlcomment.htmlstatic/
css/
style.cssjs/
script.jsrequirements.txtREADME.md

# models.pyfrom flask_sqlalchemy import SQLAlchemydb = SQLAlchemy(app)

class User(db.Model):
 id = db.Column(db.Integer, primary_key=True)
 username = db.Column(db.String(64), unique=True, nullable=False)
 email = db.Column(db.String(120), unique=True, nullable=False)
 password = db.Column(db.String(128), nullable=False)

class Article(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)
 author_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
 comments = db.relationship('Comment', backref='article', lazy=True)

class Comment(db.Model):
 id = db.Column(db.Integer, primary_key=True)
 content = db.Column(db.String(200), nullable=False)
 article_id = db.Column(db.Integer, db.ForeignKey('article.id'), nullable=False)
 user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)

# forms.pyfrom flask_wtf import FlaskFormfrom wtforms import StringField, PasswordField, SubmitFieldfrom wtforms.validators import DataRequired, Email, EqualToclass RegisterForm(FlaskForm):
 username = StringField('Username', validators=[DataRequired()])
 email = StringField('Email', validators=[DataRequired(), Email()])
 password = PasswordField('Password', validators=[DataRequired()])
 confirm_password = PasswordField('Confirm Password', validators=[DataRequired(), EqualTo('password')])
 submit = SubmitField('Register')

class LoginForm(FlaskForm):
 username = StringField('Username', validators=[DataRequired()])
 password = PasswordField('Password', validators=[DataRequired()])
 submit = SubmitField('Login')

# app.pyfrom flask import Flask, render_template, redirect, url_for, flashfrom forms import RegisterForm, LoginFormfrom models import User, Article, Commentapp = Flask(__name__)
app.config['SECRET_KEY'] = 'secret_key'
db.init_app(app)

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

@app.route('/register', methods=['GET', 'POST'])
def register():
 form = RegisterForm()
 if form.validate_on_submit():
 user = User(username=form.username.data, email=form.email.data, password=form.password.data)
 db.session.add(user)
 db.session.commit()
 flash('You have been registered successfully!', 'success')
 return redirect(url_for('login'))
 return render_template('register.html', title='Register', form=form)

@app.route('/login', methods=['GET', 'POST'])
def login():
 form = LoginForm()
 if form.validate_on_submit():
 user = User.query.filter_by(username=form.username.data).first()
 if user and user.password == form.password.data:
 flash('You have been logged in successfully!', 'success')
 return redirect(url_for('index'))
 return render_template('login.html', title='Login', form=form)

@app.route('/article/<int:article_id>')
def article(article_id):
 article = Article.query.get_or_404(article_id)
 comments = Comment.query.filter_by(article_id=article_id).all()
 return render_template('article.html', title=article.title, article=article, comments=comments)

@app.route('/comment/<int:article_id>', methods=['POST'])
def comment(article_id):
 content = request.form['content']
 user_id = current_user.id comment = Comment(content=content, article_id=article_id, user_id=user_id)
 db.session.add(comment)
 db.session.commit()
 return redirect(url_for('article', article_id=article_id))

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