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

{% extends'base.html' %}
{% block details %}

    <link rel="stylesheet" type="text/css" href="../static/css/details.css">


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

     <form action="{{ url_for('commment') }}" method="post">
     <div class="form-group">
         <textarea name="new_comment" class="form_control" rows="3" id="new_comment" placeholder="write your comment"></textarea>
          <input  name="question_id" type="hidden" value="{{ ques.id }}">/>
     </div>
         <button type="submit" class="btn-default">发送</button>
     </form>


     <h4>评论：({{ ques.comments|length }})</h4>

{% endblock %}

from flask import Flask,render_template,request,redirect,url_for,session
from flask_sqlalchemy import SQLAlchemy
from functools import wraps
import config
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)
    nickname = db.Column(db.String(20))

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'))

db.create_all()
# user=User(username='mis1234',password='111111')
# db.session.add(user)
# db.session.commit()

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

@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('base'))

@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).first()
        if user:
            if user.password == password:
                session['user'] = username
                session['userid']=user.id
                session.permanent = True
                return redirect(url_for('index'))
            else:
                return u'error username or password'

@app.route('/regist/', methods=['GET', 'POST'])
def register():
    if request.method == 'GET':
        return render_template("register.html")
    else:
        username = request.form.get('username')
        password = request.form.get('password')
        nickname = request.form.get('nickname')
        user = User.query.filter(User.username == username).first()
        if user:
            return '用户名已存在'
        else:
            user = User(username=username, password=password, nickname=nickname)
            db.session.add(user)  # 数据库，添加操作
            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('/comment/',methods=['GET','POST'])
@loginFirst
def comment():
    if request.method=='GET':
        return render_template('comment.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)  # 数据库，添加操作
        db.session.commit()
    return redirect(url_for('base'))

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

@app.route('/comment/',methods=['POST'])
@loginFirst
def comment():
    comment=request.form.get('new_comment')
    ques_id=request.form.get('question_id')
    auth_id=session.get('user')
    comm=comment(auth_id=auth_id,question_id=ques_id,detail=comment)
    db.session.add(comm)
    db.session.commit()
    return redirect(url_for('details',question_id=ques_id))

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

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


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