首页列表显示全部问答，完成问答详情页布局

1. 首页列表显示全部问答：
   1. 将数据库查询结果传递到前端页面 Question.query.all()
   2. 前端页面循环显示整个列表。
   3. 问答排序
2. 完成问答详情页布局：
   1. 包含问答的全部信息
   2. 评论区
   3. 以往评论列表显示区。
3. 在首页点击问答标题，链接到相应详情页。

 

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,os


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

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



class Question(db.Model):
    __tablename__='wenda'
    id=db.Column(db.Integer,primary_key=TabError,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('wenda'))





# db.create_all()    #是否链接成功


# 数据添加
user=User(username='ma',password='gg')
db.session.add(user)
db.session.commit()



# 数据查找
user = User.query.filter(User.username=='hh').first()
user.password='gg'
db.session.commit()


# 数据查询
user = User.query.filter(User.username=='ma').first()
print(user.username,user.password)

# 数据删除
user = User.query.filter(User.username=='ma').first()
db.session.delete(user)
db.session.commit()


# session会话连接
# filter()过滤器
# route制定路径和函数之间的关系
# def定义一个变量

@app.route('/')
def switch():
    return render_template('switch.html')
def index():
    context = {
        'question': Question.query.order_by('-creat_time').all()
    }
    return render_template('index.html',**context)
@app.route('/detail/<question_id>')
def detail(question_id):
   return render_template('detail.html',ques = question_id)

@app.route('/login/',methods=['GET','POST'])# 跳转登陆,methods定义它有两种请求方式
def login():
    if request.method == 'GET':
      return render_template('login.html')
    else:
        username = request.form.get('user')
        password = request.form.get('psw')
        user = User.query.filter(User.username == username).first()  # 判断用户名是否存在
        if user:
            if user.password==password:
                session['user'] = username
                session.permanent = True
                return   redirect(url_for('switch'))
            else:
                return u'密码错误'
        else:
            return u'用户名不存在'

@app.context_processor
def mycontext():
    username=session.get('user')
    if username:
        return {'username':username}
    else:
        return{}
@app.route('/logout')
def logout():
    session.clear()
    return  redirect(url_for('switch'))


@app.route('/register/',methods=['GET','POST'])# 跳转注册,methods定义它有两种请求方式
def register():
    if request.method == 'GET':
        return render_template('register.html')
    else:

        username = request.form.get('user')
        password = request.form.get('psw')
        nickname = request.form.get('nickname')
        user = User.query.filter(User.username == username).first() # 判断用户名是否存在
        if user:
            return u'该用户已存在'
        else:
            user = User(username=username,password=password,nickname=nickname)
            db.session.add(user)
            db.session.commit()
            return redirect(url_for('login'))

# 进入问答界面先登录功能
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('/wenda/',methods=['GET','POST'])
@loginFirst
def wenda():
    if request.method=='GET':
        return render_template('wenda.html')
    else:
        title=request.form.get('title')
        detail=request.form.get('detail')
        author_id = User.query.filter(User.username == session.get('user')).first().id
        wenda = Question(title=title,detail=detail,author_id=author_id)
        db.session.add(wenda)
        db.session.commit()
        return redirect(url_for('switch'))




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