Flask Paginate实现表格分页

flask_paginate 是 Flask 框架的一个分页扩展，用于处理分页相关的功能。它可以帮助你在 Flask Web 应用程序中实现分页功能，让用户可以浏览大量数据的不同部分。本篇博文重点讲述在Web开发中，用paginate把所有数据进行分页展示，首先通过运用第三方库实现后端分页，然后再自己编写一个分页类实现。

flask_sqlalchemy

Flask-SQLAlchemy 是 Flask 框架的一个扩展，提供了对 SQL 数据库的集成支持。它基于 SQLAlchemy 构建，简化了在 Flask 应用中使用数据库的操作。

安装 Flask-SQLAlchemy：

pip install Flask-SQLAlchemy

Flask-SQLAlchemy的使用很简单，如下是一些简单的用法；

from flask import Flask
from sqlalchemy import not_,or_,and_,desc
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)

# url的格式为：数据库的协议：//用户名：密码@ip地址：端口号（默认可以不写）/数据库名
app.config["SQLALCHEMY_DATABASE_URI"] = "sqlite:///:memory:"

# 为了解决控制台的提示
app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = False

# 创建数据库的操作对象
db = SQLAlchemy(app)

# 创建规则表
class RoleDB(db.Model):
    __tablename__ = "role"
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(16), unique=True)

    # 增加反查外键关联到UserDB
    users = db.relationship('UserDB', backref="role")

    # 当调用 Role.query.all() 会触发输出
    def __repr__(self):
        return "Role: %s | %s" % (self.id, self.name)

# 创建用户表
class UserDB(db.Model):
    __tablename__ = "user"
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(16), unique=True)
    email = db.Column(db.String(32), unique=True)
    password = db.Column(db.String(16))

    # 关联到RuleDB表中的ID上面
    role_id = db.Column(db.Integer, db.ForeignKey("role.id"))

    # 当调用 RoleDB.query.all() 会触发输出
    def __repr__(self):
        return "User: %s | %s | %s | %s" % (self.id, self.name, self.password, self.role_id)

@app.route('/')
def index():
    # 此处查询会走类内 __repr__ 输出
    print("查询所有用户数据: ", UserDB.query.all())
    print("查询所有规则数据: ", RoleDB.query.all())
    print("查询有多少个用户: ", UserDB.query.count())
    print("查询第一个用户: ", UserDB.query.first())

    # 查询过滤器
    print("查询第一条: ", UserDB.query.get(1))
    print("查询过滤器(类名+属性名): ", UserDB.query.filter(UserDB.id == 4).first())
    print("查询过滤器(属性名): ", UserDB.query.filter_by(id=4).first())

    # 查询名字结尾字符为g的所有数据 [开始/包含]
    print(UserDB.query.filter(UserDB.name.endswith("g")).all())
    print(UserDB.query.filter(UserDB.name.contains("g")).all())

    # 查询名字不等于wang的所有数据 [2种方式]
    print(UserDB.query.filter(not_(UserDB.name == "wang")).all())
    print(UserDB.query.filter(UserDB.name != "wang").all())

    #  查询 [名字和邮箱] 都以li开头的所有数据 [2种方式]
    print(UserDB.query.filter(and_(UserDB.name.startswith("li"),UserDB.email.startswith("li"))).all())
    print(UserDB.query.filter(UserDB.name.startswith("li"), UserDB.email.startswith("li")).all())

    # 查询password是 123456 或者 email 以 lyshark.com 结尾的所有数据
    print(UserDB.query.filter(or_(UserDB.password=='123456', UserDB.email.endswith('lyshark.com'))).all())

    # 查询id为 [1, 3, 5, 7, 9] 的用户列表
    print(UserDB.query.filter(UserDB.id.in_([1, 3, 5, 7, 9])).all())

    # 查询name为liu的角色数据：关系引用
    print(UserDB.query.filter_by(name="liu").first().role.name)

    # 查询所有用户数据 并以邮箱排序 [升序/降序]
    print("升序: ", UserDB.query.order_by("email").all())
    print("降序: ", UserDB.query.order_by(desc("email")).all())

    # 查询第2页的数据,每页只显示3条数据
    pages = UserDB.query.paginate(2,3,False)
    print("查询结果: {} 总页数: {} 当前页数: {}".format(pages.items,pages.pages,pages.page))

    # 完整查询调用写法
    ref = db.session.query(UserDB).filter(UserDB.name == "wang").all()
    print(ref)
    return "success"

if __name__ == "__main__":
    # 初始化数据表
    db.drop_all()
    db.create_all()

    # 插入两个规则记录
    role_admin = RoleDB(name="admin")
    db.session.add(role_admin)
    role_lyshark = RoleDB(name="lyshark")
    db.session.add(role_lyshark)
    db.session.commit()

    try:
        ua = UserDB(name='wang', email='wang@163.com', password='123456', role_id=role_admin.id)
        ub = UserDB(name='zhang', email='zhang@189.com', password='201512', role_id=role_lyshark.id)
        uc = UserDB(name='chen', email='chen@126.com', password='987654', role_id=role_lyshark.id)
        ud = UserDB(name='zhou', email='zhou@163.com', password='456789', role_id=role_admin.id)
        ue = UserDB(name='tang', email='tang@lyshark.com', password='158104', role_id=role_lyshark.id)
        uf = UserDB(name='wu', email='wu@gmail.com', password='5623514', role_id=role_lyshark.id)
        ug = UserDB(name='qian', email='qian@gmail.com', password='1543567', role_id=role_admin.id)
        uh = UserDB(name='liu', email='liu@lyshark.com', password='867322', role_id=role_admin.id)
        ui = UserDB(name='li', email='li@163.com', password='4526342', role_id=role_lyshark.id)
        uj = UserDB(name='sun', email='sun@163.com', password='235523', role_id=role_lyshark.id)
        db.session.add_all([ua, ub, uc, ud, ue, uf, ug, uh, ui, uj])
        db.session.commit()

    except Exception as e:
        # 插入失败自动回滚
        db.session.rollback()
        raise e

    app.run(debug=True)

flask_sqlalchemy 分页组件

Flask-SQLAlchemy 分页插件为 Flask 应用提供了便捷而强大的分页功能，通过 paginate() 方法返回的 Pagination 类对象，开发者能够轻松实现对大型数据集的分页展示。该插件基于 Flask-SQLAlchemy 扩展构建，简化了在 Flask 应用中进行数据库查询的分页操作。通过灵活的配置选项，开发者可以高效地管理和展示数据，提升用户体验，是构建数据驱动 Web 应用的重要利器。本文将深入介绍 Flask-SQLAlchemy 分页插件的基本使用方法以及常见配置选项，帮助开发者快速上手并充分发挥其强大的分页功能。

前端部分使用bootstrap实现分页组件，新建前端index.html文件，代码如下；

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="https://www.lyshark.com/javascript/bootstrap/5.1.3/css/bootstrap.min.css">
</head>
<body>
<div class="box box-primary">
    <div class="box-body table-responsive no-padding">
        <table class="table table-sm table-hover">
            <thread>
                <tr class="table-success">
                    <th>id</th>
                    <th>name</th>
                    <th>email</th>
                    <th>password</th>
                </tr>
            </thread>
            <tbody>
                {% for item in page_data.items %}
                    <tr class="table-primary">
                        <td>{{ item.id }}</td>
                        <td>{{ item.name }}</td>
                        <td>{{ item.email }}</td>
                        <td>{{ item.password }}</td>
                    </tr>
                {% endfor %}
            </tbody>
        </table>
    </div>

    <div class="box-footer clearfix">
        <nav class="d-flex justify-content-center" aria-label="Page navigation example">
            {% if page_data %}
                <ul class="pagination">
                    <li class="page-item"><a class="page-link" href="./1">首页</a></li>

                    {% if page_data.has_prev %}
                        <li class="page-item"><a class="page-link" href="{{ page_data.prev_num }}">上一页</a></li>
                    {% else %}
                        <li class="page-item" class="disabled"><a class="page-link" href="#">上一页</a></li>
                    {% endif %}
                    <!--
                    {% for item in page_data.iter_pages() %}
                        {% if item == page_data.page %}
                            <li class="page-item active"><a class="page-link" href="{{ item }}">{{ item }}</a></li>
                        {% else %}
                            <li class="page-item"><a class="page-link" href="{{ item }}">{{ item }}</a></li>
                        {% endif %}
                    {% endfor %}
                    -->

                    <!-- 当前页的页码/总页码 -->
                    <p>{{ page_data.page }}</p> / <p>{{ page_data.pages }}</p>

                    {% if page_data.has_next %}
                        <li class="page-item"><a class="page-link" href="{{ page_data.next_num  }}">下一页</a></li>
                    {% else %}
                        <li class="page-item" class="disabled"><a class="page-link" href="#">下一页</a></li>
                    {% endif %}
                    <li class="page-item"><a class="page-link" href="{{ page_data.pages }}">尾页</a></li>
                </ul>
            {% endif %}
        </nav>
    </div>
</div>
</body>
</html>

使用组件内的过滤器分页是非常简单的一件事，只需要调用参数后返回，后端app.py代码如下；

from flask import Flask,render_template,request
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__, template_folder="./tempate",static_folder="./tempate")

app.config["SQLALCHEMY_DATABASE_URI"] = "sqlite:///database.db"

# 设置每次请求结束后会自动提交数据库的改动
app.config['SQLALCHEMY_COMMIT_ON_TEARDOWN'] = True
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = True

# 查询时显示原始SQL语句
app.config['SQLALCHEMY_ECHO'] = False

# 创建数据库的操作对象
db = SQLAlchemy(app)

# 创建用户表
class UserDB(db.Model):
    __tablename__="user"
    id = db.Column(db.Integer,primary_key=True)
    name = db.Column(db.String(32))
    email = db.Column(db.String(32))
    password = db.Column(db.String(32))

    def __init__(self,name,email,password):
        self.name = name
        self.email = email
        self.password = password

    def __repr_(self):
        return 'User %s'%self.name

@app.route("/")
def index():
    return "<script>window.location.href='./page/1'</script>"

@app.route("/page/<int:page_number>")
def page(page_number=None):
    if page_number is None:
        page_number = 1

    page = db.session.query(UserDB).paginate(page=page_number,per_page=10,max_per_page=15)
    return render_template("index.html", page_data = page)

if __name__ == "__main__":
    # 初始化数据表
    db.drop_all()
    db.create_all()
    try:
        ua = UserDB(name='wang', email='wang@163.com', password='123456')
        ub = UserDB(name='zhang', email='zhang@189.com', password='201512')
        uc = UserDB(name='chen', email='chen@126.com', password='987654')
        ud = UserDB(name='zhou', email='zhou@163.com', password='456789')
        ue = UserDB(name='tang', email='tang@lyshark.com', password='158104')
        uf = UserDB(name='wu', email='wu@gmail.com', password='5623514')
        ug = UserDB(name='qian', email='qian@gmail.com', password='1543567')
        uh = UserDB(name='liu', email='liu@lyshark.com', password='867322')
        ui = UserDB(name='li', email='li@163.com', password='4526342')
        uj = UserDB(name='sun', email='sun@163.com', password='235523')
        db.session.add_all([ua, ub, uc, ud, ue, uf, ug, uh, ui, uj,uj,uj,uj,uj,uj,uj,uj,uj])
        db.session.commit()

    except Exception as e:
        # 插入失败自动回滚
        db.session.rollback()
        raise e
    app.run(debug=True)

flask_paginate 分页组件

Flask-Paginate 是 Flask 框架中的一个重要插件，为开发者提供了便捷而灵活的分页解决方案。通过结合 Flask 官方的分页部件，这个插件能够轻松地实现对大量数据的分页展示，为用户提供更友好的浏览体验。本文将深入介绍 Flask-Paginate 的核心功能、使用方法以及与数据库查询的协同操作，帮助开发者更好地利用这一工具来优化 Web 应用的分页展示。

前端部分使用bootstrap实现分页组件，新建前端index.html文件，代码如下；

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="https://www.lyshark.com/javascript/bootstrap/5.1.3/css/bootstrap.min.css">
</head>
<body>
<table class="table table-sm table-hover">
    <thead>
        <tr class="table-success">
            <th>序号</th>
            <th>用户ID</th>
            <th>用户名称</th>
            <th>用户邮箱</th>
            <th>用户密码</th>
        </tr>
    </thead>
    <tbody>
        {% for article in articles %}
            <tr class="table-primary">
                <td>{{ loop.index }}</td>
                <td>{{ article.id }}</td>
                <td>{{ article.name }}</td>
                <td>{{ article.email }}</td>
                <td>{{ article.password }}</td>
            </tr>
        {% endfor %}
    </tbody>
</table>
<nav class="d-flex justify-content-center" aria-label="Page navigation example">
  <ul class="pagination">
    <li class="page-item"><a class="page-link" href="./page=1">首页</a></li>
      {% if pagination.has_prev %}
           <li class="page-item"><a class="page-link" href="./page={{ prve_num }}">上一页</a></li>
      {% endif %}

        <!--获取当前列表,并全部填充到这里-->
        {% for item in pageRange %}
            <!--判断如果是当前页则直接标号为蓝色高亮-->
            {% if item == currentPage %}
                <li class="page-item active"><a class="page-link" href="./page={{ item }}">{{ item }}</a></li>
            <!--否则的话,就直接接收参数填充-->
            {% else %}
                <li class="page-item"><a class="page-link" href="./page={{ item }}">{{ item }}</a></li>
            {% endif %}
        {% endfor %}

      {% if next_end %}
          <li class="page-item"><a class="page-link" href="./page={{ next_num }}">下一页</a></li>
      {% endif %}
    <li class="page-item"><a class="page-link" href="./page={{ PageCount }}">尾页</a></li>
  </ul>
</nav>

  <div style="text-align: center;" class="alert alert-dark">
   统计: {{ pagination.page }}/{{ PageCount }} 共查询到:{{ pagination.total }} 条数据 页码列表:{{ pageRange }}
  </div>
</body>
</html>

后端就是对请求的响应，前端用户通过GET方式访问，后端获得用户页面数，查询后动态展示出来即可。

from flask import Flask,render_template,request
from flask_sqlalchemy import SQLAlchemy
from flask_paginate import Pagination,get_page_parameter
import math

app = Flask(__name__, template_folder="./tempate",static_folder="./tempate")

# url的格式为：数据库的协议：//用户名：密码@ip地址：端口号（默认可以不写）/数据库名
app.config["SQLALCHEMY_DATABASE_URI"] = "sqlite:///database.db"

# 设置每次请求结束后会自动提交数据库的改动
app.config['SQLALCHEMY_COMMIT_ON_TEARDOWN'] = True
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = True

# 查询时显示原始SQL语句
app.config['SQLALCHEMY_ECHO'] = False

# 创建数据库的操作对象
db = SQLAlchemy(app)

# 创建用户表
class UserDB(db.Model):
    __tablename__="user"
    id = db.Column(db.Integer,primary_key=True)
    name = db.Column(db.String(32))
    email = db.Column(db.String(32))
    password = db.Column(db.String(32))

    def __init__(self,name,email,password):
        self.name = name
        self.email = email
        self.password = password

    def __repr_(self):
        return 'User %s'%self.name

@app.route("/")
def index():
    return """<script>window.location.href="./page=1"</script>"""

@app.route("/page=<int:id>")
def GetPages(id):
    # 默认每页显示10个元素
    PER_PAGE = 10

    total = db.session.query(UserDB).count()
    print("总记录 {} 条".format(total))

    currentPage = request.args.get(get_page_parameter(),type=int,default=int(id))
    print("当前页码ID为 {}".format(currentPage))

    start = (currentPage-1)*PER_PAGE   # 分页起始位置
    end = start+PER_PAGE               # 分页结束位置
    print("起始位置 {} 结束位置 {}".format(start,end))

    prev_num = int(currentPage)-1
    next_num = int(currentPage)+1
    print("上一页页码 {} 下一页页码 {}".format(prev_num,next_num))

    # 计算出需要切割的页数
    page_count = math.ceil(total/PER_PAGE)
    print("切割页数 {}".format(page_count))

    pagination = Pagination(page=currentPage,total=total)

    # 执行数据库切片
    articles = db.session.query(UserDB).slice(start,end)

    # 判断,如果next_end大于总数说明到最后了
    if currentPage>=math.ceil(total/PER_PAGE):
        # 那么我们就将next_end设置为0,前端就不执行显示了
        next_end=0
    else:
        next_end=1

    # -------------------------------------------------
    # 此页面是扩展部分,用于生成当前页码,并填充到前端

    # 如果总页数小于15则一次性生成页码即可
    if page_count < 15:
        pageRange = range(1,page_count+1)

    # 总页数大于15则需要分情况生成
    elif page_count > 15:
        # 说明是第一页
        if currentPage-5 < 1:
            pageRange = range(1,11)
        # 说明是最后一页
        elif currentPage+5 > page_count:
            pageRange = range(currentPage-5,page_count)
        # 说明是中间页
        else:
            pageRange = range(currentPage-5,currentPage+5)

    # 如果都不是则返回总数
    else:
        pageRange = page_count

    print("生成的当前页码: {}".format(pageRange))

    context = {
        'pagination': pagination,
        'articles': articles,
        'prve_num': prev_num,
        'next_num': next_num,
        'PageCount': page_count,
        'pageRange': pageRange,
        'next_end': next_end,
        "currentPage": currentPage
    }
    return render_template('index.html',**context)

if __name__ == "__main__":
    db.drop_all()
    db.create_all()
    try:
        ua = UserDB(name='wang', email='wang@163.com', password='123456')
        ub = UserDB(name='zhang', email='zhang@189.com', password='201512')
        uc = UserDB(name='chen', email='chen@126.com', password='987654')
        ud = UserDB(name='zhou', email='zhou@163.com', password='456789')
        ue = UserDB(name='tang', email='tang@lyshark.com', password='158104')
        uf = UserDB(name='wu', email='wu@gmail.com', password='5623514')
        ug = UserDB(name='qian', email='qian@gmail.com', password='1543567')
        uh = UserDB(name='liu', email='liu@lyshark.com', password='867322')
        ui = UserDB(name='li', email='li@163.com', password='4526342')
        uj = UserDB(name='sun', email='sun@163.com', password='235523')
        db.session.add_all([ua, ub, uc, ud, ue, uf, ug, uh, ui, uj,uj,uj,uj,uj,uj,uj,uj,uj])
        db.session.commit()

    except Exception as e:
        # 插入失败自动回滚
        db.session.rollback()
        raise e
    app.run(debug=True)

Pagination 自写分页器

前端部分使用bootstrap实现分页组件，新建前端index.html文件，代码如下；

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="https://www.lyshark.com/javascript/bootstrap/5.1.3/css/bootstrap.min.css">
</head>
<body>
    <table class="table table-sm table-hover">
        <thead>
            <tr class="table-success">
                <th>用户ID</th>
                <th>用户名称</th>
                <th>用户邮箱</th>
                <th>用户密码</th>
            </tr>
        </thead>
        <tbody>
            {% for article in articles %}
                <tr class="table-primary">
                    <td>{{ article.id }}</td>
                    <td>{{ article.name }}</td>
                    <td>{{ article.email }}</td>
                    <td>{{ article.password }}</td>
                </tr>
            {% endfor %}
        </tbody>
    </table>

    <!--输出页码范围-->
    <nav class="d-flex justify-content-center" aria-label="Page navigation example">
         <ul class="pagination">
            {{ html|safe }}
        </ul>
    </nav>
</body>
</html>

首先需要创建一个pager.py文件，里面包含一个Pagination分页类部件。

import copy
from urllib.parse import urlencode

class Pagination(object):
    def __init__(self,current_page,total_count,base_url,params,per_page_count=10,max_pager_count=11):
        try:
            current_page = int(current_page)
        except Exception as e:
            current_page = 1
        if current_page <=0:
            current_page = 1
        self.current_page = current_page
        # 数据总条数
        self.total_count = total_count
        # 每页显示10条数据
        self.per_page_count = per_page_count
        # 页面上应该显示的最大页码
        max_page_num, div = divmod(total_count, per_page_count)
        if div:
            max_page_num += 1
        self.max_page_num = max_page_num
        # 页面上默认显示11个页码（当前页在中间）
        self.max_pager_count = max_pager_count
        self.half_max_pager_count = int((max_pager_count - 1) / 2)
        # URL前缀
        self.base_url = base_url
        # request.GET
        params = copy.deepcopy(params)
        # params._mutable = True
        get_dict = params.to_dict()
        # 包含当前列表页面所有的搜/索条件
        self.params = get_dict
    @property
    def start(self):
        return (self.current_page - 1) * self.per_page_count
    @property
    def end(self):
        return self.current_page * self.per_page_count
    def page_html(self):
        # 如果总页数 <= 11
        if self.max_page_num <= self.max_pager_count:
            pager_start = 1
            pager_end = self.max_page_num
        # 如果总页数 > 11
        else:
            # 如果当前页 <= 5
            if self.current_page <= self.half_max_pager_count:
                pager_start = 1
                pager_end = self.max_pager_count
            else:
                # 当前页 + 5 > 总页码
                if (self.current_page + self.half_max_pager_count) > self.max_page_num:
                    pager_end = self.max_page_num
                    pager_start = self.max_page_num - self.max_pager_count + 1   #倒这数11个
                else:
                    pager_start = self.current_page - self.half_max_pager_count
                    pager_end = self.current_page + self.half_max_pager_count
        page_html_list = []
        # 首页
        self.params['page'] = 1
        first_page = '<li class="page-item"><a class="page-link" href="%s?%s">首页</a></li>' % (self.base_url,urlencode(self.params),)
        page_html_list.append(first_page)
        # 上一页
        self.params["page"] = self.current_page - 1
        if self.params["page"] < 1:
            pervious_page = '<li class="page-item" class="disabled"><a class="page-link" \
            href="%s?%s" aria-label="Previous">上一页</span></a></li>' % (self.base_url, urlencode(self.params))
        else:
            pervious_page = '<li class="page-item"><a class="page-link" href = "%s?%s" \
            aria-label = "Previous" >上一页</span></a></li>' % ( self.base_url, urlencode(self.params))
        page_html_list.append(pervious_page)
        # 中间页码
        for i in range(pager_start, pager_end + 1):
            self.params['page'] = i
            if i == self.current_page:
                temp = '<li class="page-item active" class="active"><a class="page-link" \
                href="%s?%s">%s</a></li>' % (self.base_url,urlencode(self.params), i,)
            else:
                temp = '<li  class="page-item"><a class="page-link" \
                href="%s?%s">%s</a></li>' % (self.base_url,urlencode(self.params), i,)
            page_html_list.append(temp)
        # 下一页
        self.params["page"] = self.current_page + 1
        if self.params["page"] > self.max_page_num:
            self.params["page"] = self.current_page
            next_page = '<li class="page-item" class="disabled"><a class="page-link" \
            href = "%s?%s" aria-label = "Next">下一页</span></a></li >' % (self.base_url, urlencode(self.params))
        else:
            next_page = '<li class="page-item"><a class="page-link" href = "%s?%s" \
            aria-label = "Next">下一页</span></a></li>' % (self.base_url, urlencode(self.params))
        page_html_list.append(next_page)
        # 尾页
        self.params['page'] = self.max_page_num
        last_page = '<li class="page-item"><a class="page-link" href="%s?%s">尾页</a></li>' % (self.base_url, urlencode(self.params),)
        page_html_list.append(last_page)
        return ''.join(page_html_list)

主函数main.py则直接import Pagination导入分页类，然后调用Pagination函数即可实现分页了。

from flask import Flask,render_template,request
from flask_sqlalchemy import SQLAlchemy
from pager import Pagination

app = Flask(__name__, template_folder="./tempate",static_folder="./tempate")

app.config["SQLALCHEMY_DATABASE_URI"] = "sqlite:///database.db"

# 设置每次请求结束后会自动提交数据库的改动
app.config['SQLALCHEMY_COMMIT_ON_TEARDOWN'] = True
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = True

# 查询时显示原始SQL语句
app.config['SQLALCHEMY_ECHO'] = False

# 创建数据库的操作对象
db = SQLAlchemy(app)

# 创建用户表
class UserDB(db.Model):
    __tablename__="user"
    id = db.Column(db.Integer,primary_key=True)
    name = db.Column(db.String(32))
    email = db.Column(db.String(32))
    password = db.Column(db.String(32))

    def __init__(self,name,email,password):
        self.name = name
        self.email = email
        self.password = password

    def __repr_(self):
        return 'User %s'%self.name

@app.route("/")
def index():
    total = db.session.query(UserDB).count()
    print("查询总记录数: {}".format(total))

    page_number = request.args.get("page", 1)
    print("当前传入页码: {}".format(page_number))

    # 分页类 [ Pagination(传入页码/总记录数/分页URL前缀/传入数据params/每页显示数/最大显示页码 )]
    Page = Pagination(page_number, total, request.path, request.args, per_page_count=10, max_pager_count=15)

    # 对数据切片
    index = db.session.query(UserDB)[Page.start:Page.end]
    print("页面切片: {}".format(index))

    # 渲染页面
    html = Page.page_html()
    print("渲染页码页面: {}".format(html))

    return render_template("index.html",articles=index,html=html)

if __name__ == "__main__":
    # 初始化数据表
    db.drop_all()
    db.create_all()
    try:
        ua = UserDB(name='wang', email='wang@163.com', password='123456')
        ub = UserDB(name='zhang', email='zhang@189.com', password='201512')
        uc = UserDB(name='chen', email='chen@126.com', password='987654')
        ud = UserDB(name='zhou', email='zhou@163.com', password='456789')
        ue = UserDB(name='tang', email='tang@lyshark.com', password='158104')
        uf = UserDB(name='wu', email='wu@gmail.com', password='5623514')
        ug = UserDB(name='qian', email='qian@gmail.com', password='1543567')
        uh = UserDB(name='liu', email='liu@lyshark.com', password='867322')
        ui = UserDB(name='li', email='li@163.com', password='4526342')
        uj = UserDB(name='sun', email='sun@163.com', password='235523')
        db.session.add_all([ua, ub, uc, ud, ue, uf, ug, uh, ui, uj,uj,uj,uj,uj,uj,uj,uj,uj])
        db.session.commit()

    except Exception as e:
        # 插入失败自动回滚
        db.session.rollback()
        raise e
    app.run(debug=True)