from django.db import models

class Host(models.Model):

    hostname = models.CharField(max_length=32)

    # ip = models.GenericIPAddressField(protocol='ipv4')

    ip = models.CharField(max_length=32)

    port = models.IntegerField()

    hostname = "hostname%s.com"

    for i in range(302):

        models.Host.objects.create(hostname=hostname %str(i),ip="1.1.1.1",port=8080)

    return HttpResponse("...")

"""

分页组件：

    使用方法：

        视图函数：

            from utils.pager import Pagination

            def host(request):

                all_count = models.Host.objects.all().count()

                # page_obj = Pagination(request.GET.get('page'),all_count,'/host/')

                page_obj = Pagination(request.GET.get('page'),all_count,request.path_info)

                host_list = models.Host.objects.all()[page_obj.start:page_obj.end]

                return render(request,'host.html',{'host_list':host_list,'page_html':  page_obj.page_html()})

        HTML：

            <!-- 最新版本的 Bootstrap 核心 CSS 文件 -->

            <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">

            <style>

                .pager .active>a {

                    z-index: 3;

                    color: #fff;

                    cursor: default;

                    background-color: #337ab7;

                    border-color: #337ab7;

                }

                .pager li>a:hover {

                    z-index: 5;

                    color: #fff;

                    cursor: default;

                    background-color: #337ab7;

                    border-color: #337ab7;

                }

                .pager li>a{

                    border-radius: 5px;

                    margin: 0 3px;

                    padding: 3px 5px;

                    min-width:40px;

                }

            </style>

"""

from django.utils.safestring import mark_safe

class Pagination(object):

    def __init__(self,current_page,total_count,base_url, per_page_count=10,max_pager_num=11):

        """

        :param current_page: 用户请求的当前页

        :param per_page_count: 每页显示的数据条数

        :param total_count:  数据库中查询到的数据总条数

        :param max_pager_num: 页面上最多显示的页码

        """

        self.base_url = base_url

        total_page_count, div = divmod(total_count, per_page_count)

        if div:

            total_page_count += 1

        self.total_page_count = total_page_count

        try:

            current_page = int(current_page)

        except Exception as e:

            current_page = 1

        if current_page > total_page_count:

            current_page = total_page_count

        self.current_page = current_page

        self.per_page_count = per_page_count

        self.total_count = total_count

        self.max_pager_num = max_pager_num

        self.half_max_pager_num = int(max_pager_num/2)

    @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):

        page_html_list = []

        page_html_list.append("<ul>")

        if self.current_page <= 1:

            prev = "<li><a href='#'>上一页</a></li>"

        else:

            prev = "<li><a href='%s?page=%s'>上一页</a></li>" % (self.base_url,self.current_page - 1,)

        page_html_list.append(prev)

        max_pager_num = 11

        half_max_pager_num = int(max_pager_num / 2)

        # 数据总页数 < 页面上最大显示的页码个数

        if self.total_page_count <= max_pager_num:

            page_start = 1

            page_end = self.total_page_count

        else:

            # 数据比较多，已经超过11个页码

            # 如果当前页 <=5,显示 1-11

            if self.current_page <= half_max_pager_num:

                page_start = 1

                page_end = max_pager_num

            else:

                # 当前页 >= 6

                if (self.current_page + 5) > self.total_page_count:

                    page_end = self.total_page_count

                    # page_start = current_page - 5

                    page_start = self.total_page_count - max_pager_num + 1

                else:

                    page_start = self.current_page - half_max_pager_num  # 当前页 - 5

                    page_end = self.current_page + half_max_pager_num  # 当前页 + 5

        for i in range(page_start, page_end + 1):

            if self.current_page == i:

                tag = "<li class='active'><a href='%s?page=%s'>%s</a></li>" % (self.base_url,i, i,)

            else:

                tag = "<li><a href='%s?page=%s'>%s</a></li>" % (self.base_url,i, i,)

            page_html_list.append(tag)

        # 下一页

        if self.current_page >= self.total_page_count:

            nex = "<li><a href='#'>下一页</a></li>"

        else:

            nex = "<li><a href='%s?page=%s'>下一页</a></li>" % (self.base_url,self.current_page + 1,)

        page_html_list.append(nex)

        page_html_list.append("</ul>")

        return mark_safe("".join(page_html_list))

{% block css %}

    <!-- 最新版本的 Bootstrap 核心 CSS 文件 -->

    <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">

    <style>

        .pager .active>a {

            z-index: 3;

            color: #fff;

            cursor: default;

            background-color: #337ab7;

            border-color: #337ab7;

        }

        .pager li>a:hover {

            z-index: 5;

            color: #fff;

            cursor: default;

            background-color: #337ab7;

            border-color: #337ab7;

        }

        .pager li>a{

            border-radius: 5px;

            margin: 0 3px;

            padding: 3px 5px;

            min-width:40px;

        }

    </style>

{% endblock %}

{% block body %}

    <div class="container">

        <table class="table table-striped">

            <thead>

                <tr>

                    <th>ID</th>

                    <th>主机名</th>

                    <th>IP</th>

                    <th>端口</th>

                </tr>

            </thead>

            <tbody>

                {% for row in host_list %}

                    <tr>

                        <td>{{ row.id }}</td>

                        <td>{{ row.hostname }}</td>

                        <td>{{ row.ip }}</td>

                        <td>{{ row.port }}</td>

                    </tr>

                {% endfor %}

            </tbody>

        </table>

        <div class="pager">

            {{ page_html}}

        </div>

    </div>

{% endblock %}