完成评论功能

• 定义评论的视图函数
• @app.route('/comment/',methods=['POST'])
• def comment()：
• 读取前端页面数据，保存到数据库中
• 用<input type="hidden" 方法获取前端的"question_id" 
• 显示评论次数
• 要求评论前登录
• 尝试实现详情页面下的评论列表显示

from flask import Flask, render_template, request, redirect, url_for, session
from flask_sqlalchemy import SQLAlchemy
import config
from functools import wraps
from datetime import datetime

app = Flask(__name__)
app.config.from_object(config)
db = SQLAlchemy(app)


class User(db.Model):
    __tablename__ = 'user'
    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    username = db.Column(db.String(20), nullable=False)
    password = db.Column(db.String(20), nullable=False)


class Question(db.Model):
    __tablename__ = 'question'
    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    title = db.Column(db.String(100), nullable=False)
    detail = db.Column(db.Text, nullable=False)
    creat_time = db.Column(db.DateTime, default=datetime.now)
    author_id = db.Column(db.Integer, db.ForeignKey('user.id'))
    author = db.relationship('User', backref=db.backref('question'))

class Comment(db.Model):
    __tablename__ = 'comment'
    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    author_id = db.Column(db.Integer, db.ForeignKey('user.id'))
    question_id = db.Column(db.Integer, db.ForeignKey('question.id'))
    creat_time=db.Column(db.DateTime, default=datetime.now)
    detail=db.Column(db.Text,nullable=False)
    question=db.relationship('Question',backref=db.backref('comments'))
    author=db.relationship('User',backref=db.backref('comments'))


db.create_all()


@app.route('/')
def daohang():
    context={
        'questions':Question.query.order_by('creat_time').all()
    }
    return render_template('index.html',**context)

@app.route('/detail/<question_id>',methods=['GET','POST'])
def detail(question_id):
    quest=Question.query.filter(Question.id == question_id).first()
    return render_template('detail.html',ques=quest)


def loginFirst(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        if session.get('user'):
            return func(*args, **kwargs)
        else:
            return redirect(url_for('login'))
    return wrapper

@app.route('/comment/',methods=['POST'])
@loginFirst
def comment():
    comment=request.form.get('new_comment')
    ques_id=request.form.get('question_id')
    auth_id=User.query.filter(User.username==session.get('user')).first().id
    comm=Comment(author_id=auth_id,question_id=ques_id,detail=comment)
    db.session.add(comm)
    db.session.commit()
    return redirect(url_for('detail',question_id=ques_id))




@app.route('/login/', methods=['GET', 'POST'])
def login():
    if request.method == 'GET':
        return render_template('login.html')
    else:
        username = request.form.get('username')
        password = request.form.get('password')
        user = User.query.filter(User.username == username, User.password == password).first()
        if user:
            session['user'] = username
            session.permanent = True
            return redirect(url_for('index'))
        else:
            return 'error username or password'



@app.context_processor
def mycontext():
    usern = session.get('user')
    if usern:
        return {'username': usern}
    else:
        return {}


@app.route('/logout/')
def logout():
    session.clear()
    return redirect(url_for('register'))


@app.route('/register/', methods=['GET', 'POST'])
def regist():
    if request.method == 'GET':
        return render_template('register.html')
    else:
        username = request.form.get('username')
        password = request.form.get('password')
        user = User.query.filter(User.username == username).first()
        if user:
            return 'username existed'
        else:
            user = User(username=username, password=password)
            db.session.add(user)
            db.session.commit()
            return redirect(url_for('login'))





@app.route('/question/', methods=['GET', 'POST'])
@loginFirst
def question():
    if request.method == 'GET':
        return render_template('question.html')
    else:
        title = request.form.get('title')
        detail = request.form.get('detail')
        author_id = User.query.filter(User.username == session.get('user')).first().id
        question = Question(title=title, detail=detail, author_id=author_id)
        db.session.add(question)
        db.session.commit()
        return redirect(url_for('index'))

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

{% extends base.html' %}
{% block title %}问答详情{% endblock %}

{% block main %}
    <div class="page-header">
        <h3>Title {{ ques.title }}<br><small>{{ ques.author.username }} <span class="badge">{{ ques.creat_time }}</span></small>></h3>
    </div>
    <p class="lead">detail{{ ques.detail }}</p>
    <hr>

    <form action="{{ url_for('comment') }}"method="post" style="...">
        <div class="form-group">
            <textarea name="new_comment" id="new-comment" class="form-control" rows="3"
                      placeholder="write your comment"></textarea>
            <input type="hidden" name="question_id" value="{{ ques.id }}">
        </div>
        <button type="submit" class="btn btn-default">发送</button>
    </form>
    <h4>评论:({{ ques.comments|length }})</h4>>
    <ul class="list-group" style="margin:10px"></ul>>
{% endblock %}