说明
实验目标
实现当前登录用户的事务浏览、添加、删除 操作
实现
首先，在我们的 todolist\fORMs.py 中添加事务添加对应的表单类 ThingForm，示例代码如下所示：
from flask_wtf import FlaskForm
from wtforms import StringField, SubmitField, TextAreaField, PassWordField
from wtforms.validators import DataRequired, Length, Email, EqualTo, ValidationError
from models import User
class ReGISterForm(FlaskForm):
username = StringField('用户名：', validators=[
DataRequired(), Length(min=6, max=20)])
email = StringField('邮箱：', validators=[DataRequired(), Email()])
pwd = PasswordField('密码：', validators=[
DataRequired(), Length(min=8, max=120)])
confirm = PasswordField('确认密码：', validators=[
DataRequired(), EqualTo('pwd')])
submit = SubmitField('提交')
def validate_username(self, username):
user = User.query.filter_by(name=username.data).first()
if user:
raise ValidationError("用户昵称已存在。")
def validate_email(self, email):
user = User.query.filter_by(email=email.data).first()
if user:
raise ValidationError('邮箱已存在.')
class LoginForm(FlaskForm):
username = StringField('用户名：', validators=[
DataRequired(), Length(min=6, max=20)])
password = PasswordField('密码：', validators=[DataRequired()])
submit = SubmitField('登陆')
def validate_username(self, username):
user = User.query.filter_by(name=username.data)
if not user:
raise ValidationError('用户名不存在。')
class ThingForm(FlaskForm):
title = StringField('标题：', validators=[
DataRequired(), Length(min=6, max=20)])
text = TextAreaField('内容：', validators=[DataRequired()])
submit = SubmitField('提交')接着修改 todolist\app\views.py ，添加当前用户事务的添加、删除，示例代码如下所示：
from flask import render_template, redirect, url_for, flash, request
from flask_login import login_user, login_required, current_user, loGout_user
from app import app, db
from forms import ThingForm, RegisterForm, LoginForm
from models import User, Thing
@app.context_processor
def inject_user():
user = User.query.first()
return dict(user=user)
@app.route('/', methods=['GET', 'POST'])
@app.route('/index', methods=['GET', 'POST'])
def index():
form = ThingForm()
if not current_user.is_authenticated:
return redirect(url_for('login'))
if request.method == 'POST' and form.validate_on_submit():
user_id = current_user.id
title = form.title.data
text = form.text.data
thing = Thing(user_id=user_id, title=title, text=text)
db.session.add(thing)
db.session.commit()
flash('添加成功')
page = request.args.get('page', 1, type=int)
things = current_user.things.order_by(
Thing.add_date.desc()).paginate(page, 2, False)
print(things)
return render_template('index.html', title="首页", form=form, things=things)
@app.route('/login', methods=['POST', 'GET'])
def login():
form = LoginForm()
if form.validate_on_submit():
name = form.username.data
pwd = form.password.data
user = User.query.filter_by(name=name).first()
if user and user.check_password_hash(pwd):
login_user(user)
flash('登陆成功。', category='info')
return redirect(url_for('index'))
else:
flash("密码或账户错误。", category='error')
return render_template('login.html', title='登录', form=form)
@app.route('/logout')
@login_required
def logout():
logout_user()
flash('再见！')
return redirect(url_for('login'))
@app.route('/register', methods=['POST', 'GET'])
def register():
form = RegisterForm()
if form.validate_on_submit():
username = form.username.data
email = form.email.data
pwd = form.pwd.data
user = User(name=username, email=email)
user.generate_password_hash(pwd)
db.session.add(user)
db.session.commit()
flash('注册成功', category='info')
return redirect(url_for('login'))
return render_template('register.html', title='注册', form=form)
@app.route('/delete/<int:id>')
@login_required
def delete(id):
thing = Thing.query.get(id)
if thing:
db.session.delete(thing)
db.session.commit()
return redirect(url_for('index'))最后，完善 todolist\app\templates\index.html，添加数据展示相关代码，示例代码如下所示：
{% extends 'base.html' %} {% block content %} {% if current_user.is_authenticated and user %}
<h1 class="m-4">{{ current_user.name }},欢迎回来</h1>
{% endif %}
<div class="container-fluid">
<p>
<a class="btn btn-primary" data-toggle="collapse" href="#collapseExample" role="button" aria-expanded="false" aria-controls="collapseExample">
添加新事务
</a>
</p>
<div class="collapse" id="collapseExample">
<div class="card card-body mb-4">
{% from 'bootstrap/form.html' import render_form %} {{ render_form(form) }}
</div>
</div>
<ul class="list-group">
{% for thing in things.items %}
<li class="list-group-item">
<h4 style="display:block;float:left;padding-top:2px">
{{ thing.title }}
</h4>
<div style="display:block;float: right;">
<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#exampleModalCenter{{thing.id}}">查看</button>
<a class="btn btn-danger" href='/delete/{{ thing.id }}'>删除</a>
</div>
</li>
<div class="modal fade" id="exampleModalCenter{{thing.id}}" tabindex="-1" role="dialog" aria-labelledby="exampleModalCenterTitle" aria-hidden="true">
<div class="modal-dialog modal-dialog-centered" role="document">
<div class="modal-content">
<div class="modal-header">
<h5 class="modal-title" id="exampleModalLongTitle">{{ thing.title }}</h5>
</div>
<div class="modal-body">
{{ thing.text }}
</div>
<div class="modal-footer">
<small>{{ thing.add_date }}</small>
<button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
</div>
</div>
</div>
</div>
{% endfor %}
</ul>
<nav aria-label="Page navigation example" class="m-4">
<ul class="pagination justify-content-center">
<li class="page-item {% if not things.has_prev %}disabled{% endif %}">
<a class="page-link" href="{{ url_for('index',page=things.prev_num) }}">上一页</a>
</li>
{% for page in things.iter_pages(1,1,3,2) %} {% if page %}
<li class="page-item {%if page==things.page%}active{%endif%}">
<a class="page-link" href="{{ url_for('index',page=page) }}">{{page}}</a>
</li>
{% else %}
<li class="page-item disabled">
<a class="page-link" href="#">…</a>
</li>
{% endif %} {% endfor %}
<li class="page-item {% if not things.has_next %}disabled{% endif %}">
<a class="page-link" href="{{ url_for('index',page=things.next_num) }}">下一页</a>
</li>
</ul>
</nav>
</div>
{% endblock %}此时，当我们运行起我们的网站后进入注册页面 Http://127.0.0.1:5000 就可以进行当前登录用户的事务录入、查看、删除、和事务分页的效果了。
补充
一个 Pagination 对象的常用属性有：
- items 当前页面中的所有记录(比如当前页上有5条记录，items就是以列表形式组织这5个记录)
- query 当前页的query对象(通过query对象调用paginate方法获得的Pagination对象)
- page 当前页码(比如当前页是第5页，返回5)
- prev_num 上一页页码
- next_num 下一页页码
- has_next 是否有下一页 True/False
- has_prev 是否有上一页 True/False
- pages 查询得到的总页数 per_page 每页显示的记录条数
- total 总的记录条数
常用方法有：
- prev() 上一页的分页对象Pagination
- next() 下一页的分页对象Pagination
- iter_pages(left_edge=2,left_current=2,right_current=5,right_edge=2)
- iter_pages 用来获得针对当前页的应显示的分页页码列表。
- 假设当前共有100页，当前页为50页，按照默认的参数设置调用iter_pages获得的列表为：[1,2,None,48,49,50,51,52,53,54,55,None,99,100]
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