从首页问答标题到问答详情页

1. 主PY文件写视图函数，带id参数。 

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

2. 首页标题的标签做带参数的链接。
         {{ url_for('detail',question_id = foo.id) }}
   
   
3. 在详情页将数据的显示在恰当的位置。 

   {{ ques.title}}
   {{ ques.id  }}{{  ques.creat_time }}

   {{ ques.author.username }} 
   {{ ques.detail }}

4. 建立评论的对象关系映射：

   class Comment(db.Model):
       __tablename__='comment'

5.  尝试实现发布评论。

   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):
       __table__name = '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(50))
   
   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('/index/')
   def index():
       context = {
               'question':Question.query.all()
           }
       return render_template('index.html',**context)
   
   @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('/regist/',methods=['GET','POST'])
   def regist():
       if request.method=='GET':
           return render_template('regist.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 u'username existed'
           else:
               user=User (username=username,password=password,nickname=nickname)
               db.session.add(user)
               db.session.commit()
               return redirect(url_for('login'))
   
   
   
   @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
                   return redirect(url_for('index'))
               else:
                   return u'password error'
           else:
               return u'username is not existed'
   
   
   @app.route('/logout/')
   def logout():
       session.clear()
       return redirect(url_for('index'))
   
   
   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('index'))
   
   
   
   @app.context_processor
   def mycontext():
       usern=session.get('user')
       if usern:
           return{'username':usern}
       else:
           return{}
   
   
   if __name__ == '__main__':
       app.run(debug=True)

   {% extends 'base.html' %}
   
   {% block title %}首页{% endblock %}
   
   {% block head %}
       <link href="{{ url_for('static',filename='css/index.css') }}" rel="stylesheet" type="text/css">
       <script src="{{ url_for('static',filename='js/index.js') }}"></script>
   {% endblock %}
   
   {% block main %}
   <p>{{ username }}contextx</p>
       <ul class="list-group"style="">
       {% for foo in questions %}
               <li class="list-group-item">
                   <span class="glyphicon glyphicon-leaf"aria-hidden="true"></span>
                   <a href="{{ url_for('detail',question_id = foo.id) }}">{{ foo.title }}</a>
                   <p style="text-indent:18px">{{ foo.detail }}</p>
                   <span class="glyphicon glyphicon-user" aria-hidden="true"></span>
                   <a href="{{ url_for('usercenter',user_id = foo.author_id) }}">{{ foo.author.username }} 评论：{{ foo.comments|length }}</a>
   
                   <span class="badge">{{ foo.creat_time }}</span>
   
               </li>
   
       </ul>
       
   
   <body background="http://f10.baidu.com/it/u=4181379019,968220141&fm=72"></body>
   
   {% endblock %}

   {% extends 'base.html' %}
   
   {% block title %}反馈中心{% endblock %}
   
   {% block main %}
       <div class="divtouming">
               <h3>{{ ques.title }}<br><small>{{ ques.auther.username }} <span class="badge">{{ ques.creat_time }}</span></small></h3>
       </div>
       <div class="panel panel-default" style="width: 800px">
           <div class="panel-body">
               <form class="form-horizontal" role="form">
                   <div class="form-group">
                       <label for="fankuititle" class="col-sm-2 control-label">反馈原因</label>
                       <div class="col-sm-10">
                           <input type="text" class="form-control" id="fankuititle">
                       </div>
                   </div>
                   <div class="form-group">
                       <label for="fankuitext" class="col-sm-2 control-label">详情</label>
                       <div class="col-sm-10">
                           <textarea id="fankuitext" rows="5" cols="87"></textarea>
                       </div>
                   </div>
                   <div class="form-group">
                       <div class="col-sm-offset-2 col-sm-10">
                           <button type="submit" class="btn btn-default">提交</button>
                       </div>
                   </div>
               </form>
           </div>
       </div></div>
   {% endblock %}