Python Flask 框架开发

1. Python 代码示例（使用 Flask 框架）

1.1 安装依赖库

pip install flask flask_sqlalchemy flask_login flask_wtf

1.2 主应用文件 app.py

from flask import Flask, request, jsonify, redirect, url_for, render_template, flash
from flask_sqlalchemy import SQLAlchemy
from flask_login import LoginManager, UserMixin, login_user, login_required, logout_user, current_user
from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField, SubmitField, ValidationError, SelectField
from wtforms.validators import DataRequired, Length, EqualTo
import osapp = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///site.db'
app.config['SECRET_KEY'] = os.urandom(24)
db = SQLAlchemy(app)
login_manager = LoginManager(app)
login_manager.login_view = 'login'class User(db.Model, UserMixin):id = db.Column(db.Integer, primary_key=True)username = db.Column(db.String(20), unique=True, nullable=False)password = db.Column(db.String(60), nullable=False)role = db.Column(db.String(20), nullable=False, default='user')  # 'user' or 'admin'class Order(db.Model):id = db.Column(db.Integer, primary_key=True)order_number = db.Column(db.String(20), unique=True, nullable=False)status = db.Column(db.String(20), nullable=False)user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)user = db.relationship('User', backref='orders')class ElectronicWaybill(db.Model):id = db.Column(db.Integer, primary_key=True)content = db.Column(db.String(255), nullable=False)order_id = db.Column(db.Integer, db.ForeignKey('order.id'), nullable=False)order = db.relationship('Order', backref='electronic_waybills')class RegistrationForm(FlaskForm):username = StringField('Username', validators=[DataRequired(), Length(min=4, max=20)])password = PasswordField('Password', validators=[DataRequired(), Length(min=6, max=60)])confirm_password = PasswordField('Confirm Password', validators=[DataRequired(), EqualTo('password')])role = SelectField('Role', choices=[('user', 'User'), ('admin', 'Admin')], default='user')submit = SubmitField('Register')def validate_username(self, field):if User.query.filter_by(username=field.data).first():raise ValidationError('Username is already in use.')@login_manager.user_loader
def load_user(user_id):return User.query.get(int(user_id))@app.route('/login', methods=['GET', 'POST'])
def login():if request.method == 'POST':username = request.form['username']password = request.form['password']user = User.query.filter_by(username=username).first()if user and user.password == password:login_user(user)return redirect(url_for('dashboard'))return render_template('login.html')@app.route('/logout')
@login_required
def logout():logout_user()return redirect(url_for('login'))@app.route('/register', methods=['GET', 'POST'])
def register():form = RegistrationForm()if form.validate_on_submit():user = User(username=form.username.data, password=form.password.data, role=form.role.data)db.session.add(user)db.session.commit()flash('Registration successful. You can now log in.', 'success')return redirect(url_for('login'))return render_template('register.html', form=form)@app.route('/dashboard')
@login_required
def dashboard():orders = Order.query.filter_by(user_id=current_user.id).all()order_list = [{'id': order.id, 'order_number': order.order_number, 'status': order.status} for order in orders]return jsonify({'orders': order_list, 'user_role': current_user.role})# 其他路由和功能可以根据需求添加
# ...if __name__ == '__main__':db.create_all()app.run(debug=True)

-- 创建 User 表
CREATE TABLE "user" (id INTEGER NOT NULL,username VARCHAR(20) NOT NULL,password VARCHAR(60) NOT NULL,role VARCHAR(20) NOT NULL DEFAULT 'user',PRIMARY KEY (id),UNIQUE (username)
);-- 创建 Order 表
CREATE TABLE order (id INTEGER NOT NULL,order_number VARCHAR(20) NOT NULL,status VARCHAR(20) NOT NULL,user_id INTEGER NOT NULL,PRIMARY KEY (id),UNIQUE (order_number),FOREIGN KEY(user_id) REFERENCES "user" (id)
);-- 创建 ElectronicWaybill 表
CREATE TABLE electronic_waybill (id INTEGER NOT NULL,content VARCHAR(255) NOT NULL,order_id INTEGER NOT NULL,PRIMARY KEY (id),FOREIGN KEY(order_id) REFERENCES "order" (id)
);

from your_app import db, User, Order, ElectronicWaybill# 创建用户
user1 = User(username='user1', password='password1', role='user')
user2 = User(username='user2', password='password2', role='admin')db.session.add_all([user1, user2])
db.session.commit()# 创建订单
order1 = Order(order_number='ORD123', status='Processing', user_id=user1.id)
order2 = Order(order_number='ORD456', status='Shipped', user_id=user2.id)db.session.add_all([order1, order2])
db.session.commit()# 创建电子面单
waybill1 = ElectronicWaybill(content='Content for order 1', order_id=order1.id)
waybill2 = ElectronicWaybill(content='Content for order 2', order_id=order2.id)db.session.add_all([waybill1, waybill2])
db.session.commit()