完成评论功能

1. 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
2. 用<input type="hidden" 方法获取前端的"question_id" 
3. 显示评论次数
4. 要求评论前登录
5. 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
from functools import wraps
from datetime import datetime
import config


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 base():
    return render_template('base.html')

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




@app.route('/login/',methods=['GET','POST'])
def login():
    if request.method == 'GET':
        return render_template('login.html')
    else:
        usern = request.form.get('username')
        passw = request.form.get('password')
        user = User.query.filter(User.username == usern).first()
        if user:
            if user.password == passw:
                session['user'] = usern
                return redirect(url_for('shouye'))
            else:
                return u'password error'
        else:
            return u'username is not existed.'



@app.route('/zhuce/',methods=['GET','POST'])
def zhuce():
    if request.method == 'GET':
        return render_template('zhuce.html')
    else:
        usern = request.form.get('username')
        passw = request.form.get('password')
        user = User.query.filter(User.username == usern).first()
        if user:
            return u'username existed'
        else:
            user1 = User(username=usern, password=passw)
            db.session.add(user1)
            db.session.commit()
            return redirect(url_for('login'))


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('/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('shouye'))


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


@app.route('/comment/',methods=['POST'])

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.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('shouye'))


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

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


                              
                               <span >{{ ques.create_time }}</span>
                       <p class="abstract">{{ ques.detail }}</p>

                       <form action="{{ url_for('comment') }}" method="post">
                       <div class="form-group">

{% block main %}

<ul class="list-group">
                           <a  class="author" href="">{{ ques.author.username }}</a>
                           <br>
                       <a class="title"  href="">{{ ques.title }}</a> <br>

<textarea class="inputFramework" rows="6" id="new_comment" name="new_comment"></textarea> <input name="question_id" type="hidden" value="{{ ques.id }}" /> </div> <button type="submit" class="btn btn-default">发送</button> </form> </ul> <h4>评论：({{ ques.comments|length }})</h4> {% for foo in comment %} <li class="list-group-item"> <span class="glyphicon glyphicon-leaf" aria-hidden="true"></span> <p class="detail">{{ foo.detail }}</p> <a href="#">{{ foo.author.username }} </a> <span class="badge">{{ foo.creat_time }}</span> </li> </div> </div> {% endblock %}