django组件

django内置序列化组件(drf前身)

"""前后端分离的项目,视图函数只需要返回json格式的数据即可"""
from app01 import models
from django.http import JsonResponse

def ab_ser_func(request):
    # 1.查询所有的书籍对象
    book_queryset = models.Book.objects.all()  # queryset [对象、对象]
    # 2.封装成大字典返回
    data_dict = {}
    for book_obj in book_queryset:
        temp_dict = {}
        temp_dict['pk'] = book_obj.pk
        temp_dict['title'] = book_obj.title
        temp_dict['price'] = book_obj.price
        temp_dict['info'] = book_obj.info
        data_dict[book_obj.pk] = temp_dict  # {1:{},2:{},3:{},4:{}}
    return JsonResponse(data_dict)

序列化组件(django自带 后续学更厉害的drf)
# 导入内置序列化模块
from django.core import serializers
# 调用该模块下的方法，第一个参数是你想以什么样的方式序列化你的数据
res = serializers.serialize('json', book_queryset)
return HttpResponse(res)

批量操作数据

def ab_bk_func(request):
    # 1.往books表中插入10万条数据
    # for i in range(1,100000);
    	# models.Books.objects.create(title='第%s本书'% i)
     """直接循环插入，10s 500条左右"""
    book_obj_list = []
    for i in range(1,100000):
        book_obj = models.Books01(title='第%本书' % i)   # 循环创建书籍对象,没有操作ORM
        book_obj_list.append(book_obj)
    # 批量插入数据
    models.Books01.objects.bulk_create(book_obj_list)
    """使用ORM提供的批量插入操作 5s 10万条左右"""
    # 查询出所有的表中并展示到前端页面
    book_querset = models.Book01.objects.all()
    return render(request,'Bkpage.html',locals())

分页器思路

推导流程:
    1.queryset支持切片操作(正数)
    2.研究各个参数之间的数学关系
    	每页固定展示多少条数据、起始位置、终止位置
    3.自定义页码参数
    		current_page = request.GET.get('page')
    4.前端展示分页器样式
    5.总页码数问题
    	divmod内置函数，括号内放两个数字，结果是商和余数
    6.前端页面页码个数渲染问题
    	后端产生 前端渲染

自定义分页器

class Pagination(object):
    def __init__(self, current_page, all_count, per_page_num=2, pager_count=11):
        """
        封装分页相关数据
        :param current_page: 当前页
        :param all_count:    数据库中的数据总条数
        :param per_page_num: 每页显示的数据条数
        :param pager_count:  最多显示的页码个数
        """
        try:
            current_page = int(current_page)
        except Exception as e:
            current_page = 1
 
        if current_page < 1:
            current_page = 1
 
        self.current_page = current_page
 
        self.all_count = all_count
        self.per_page_num = per_page_num
 
        # 总页码
        all_pager, tmp = divmod(all_count, per_page_num)
        if tmp:
            all_pager += 1
        self.all_pager = all_pager
 
        self.pager_count = pager_count
        self.pager_count_half = int((pager_count - 1) / 2)
 
    @property
    def start(self):
        return (self.current_page - 1) * self.per_page_num
 
    @property
    def end(self):
        return self.current_page * self.per_page_num
 
    def page_html(self):
        # 如果总页码 < 11个：
        if self.all_pager <= self.pager_count:
            pager_start = 1
            pager_end = self.all_pager + 1
        # 总页码  > 11
        else:
            # 当前页如果<=页面上最多显示11/2个页码
            if self.current_page <= self.pager_count_half:
                pager_start = 1
                pager_end = self.pager_count + 1
 
            # 当前页大于5
            else:
                # 页码翻到最后
                if (self.current_page + self.pager_count_half) > self.all_pager:
                    pager_end = self.all_pager + 1
                    pager_start = self.all_pager - self.pager_count + 1
                else:
                    pager_start = self.current_page - self.pager_count_half
                    pager_end = self.current_page + self.pager_count_half + 1
 
        page_html_list = []
        # 添加前面的nav和ul标签
        page_html_list.append('''
                    <nav aria-label='Page navigation>'
                    <ul class='pagination'>
                ''')
        first_page = '<li><a href="?page=%s">首页</a></li>' % (1)
        page_html_list.append(first_page)
 
        if self.current_page <= 1:
            prev_page = '<li class="disabled"><a href="#">上一页</a></li>'
        else:
            prev_page = '<li><a href="?page=%s">上一页</a></li>' % (self.current_page - 1,)
 
        page_html_list.append(prev_page)
 
        for i in range(pager_start, pager_end):
            if i == self.current_page:
                temp = '<li class="active"><a href="?page=%s">%s</a></li>' % (i, i,)
            else:
                temp = '<li><a href="?page=%s">%s</a></li>' % (i, i,)
            page_html_list.append(temp)
 
        if self.current_page >= self.all_pager:
            next_page = '<li class="disabled"><a href="#">下一页</a></li>'
        else:
            next_page = '<li><a href="?page=%s">下一页</a></li>' % (self.current_page + 1,)
        page_html_list.append(next_page)
 
        last_page = '<li><a href="?page=%s">尾页</a></li>' % (self.all_pager,)
        page_html_list.append(last_page)
        # 尾部添加标签
        page_html_list.append('''
                                           </nav>
                                           </ul>
                                       ''')
        return ''.join(page_html_list)

自定义分页器的使用

后端写法;

def ab_pg_func(request):
    book_queryset = models.Books01.objects.all()
    from app01.utils.mypage import Pagination   # 导入自定义分页器类
    current_page = request.GET.get('page')   # 获取前端的get请求是第几页
    page_obj = Pagination(current_page=current_page, all_count=book_queryset.count())
    "产生一个分页对象,传参，当前页，数据的总数"
    page_queryset = book_queryset[page_obj.start:page_obj.end]
    "对全部的数据对象进行切割"
    return render(request, 'pgPage.html', locals())

前端写法:

<div class="container">
    <div class="row">
        <div class="col-md-8 col-md-offset-2">
            {% for book in page_queryset %}
            <p>{{ book.title }}</p>
            {% endfor %}
            {{ page_obj.page_html|safe }}
        </div>
    </div>
</div>

form组件

小需求:获取用户数据并发送给后端校验，后端返回不符合校验规则的提示信心
传统写法:
    def ajax_func(request):
    if request.method == 'POST':
        name = request.POST.get('name')
        pwd = request.POST.get('pwd')
        user_dict = {'username': '', 'password': ''}
        if name == 'jason':
            user_dict['username'] = '账号不能是jason'
        if pwd == '123':
            user_dict['password'] = '密码不能是123'
            return render(request, 'ajax_func.html', locals())
    return render(request, 'ajax_func.html')

form组件功能

1.自动校验数据

class MyForm(forms.Form):   # 需要先定义好我们的要求
    username = forms.CharField(min_length=3, max_length=8)
    "规定字符串的最长是8，最短是3"
    age = forms.IntegerField(min_value=0, max_value=100)
    "规定年龄的位正整数，最小是0，最大是100"
    email = forms.EmailField()
    "规定email必须是邮箱的格式"


def ajax_func(request):
    if request.method == 'POST':
        name = request.POST.get('name')   # 获取前端数据
        age = request.POST.get('age')
        email = request.POST.get('email')
        form_obj = MyForm({'username': name, 'age': age, 'email': email})  # 产生对象
        form_obj.is_valid()   # 必须先判断拿到的数据是不是符合要求的
        # form_date =
        print(form_obj.cleaned_data)   # 拿符合数据的要求
        form_err = form_obj.errors   # 不符合数据的要求
        return render(request, 'ajax_func.html', locals())
    return render(request, 'ajax_func.html')
1.只会校验类中定义好的字段对应的数据，多穿的根本不做任何操作
2.默认情况下类中定义好的字段都是必填的

2.自动生成标签

3.自动展示信息