django学习

 1、上架时间小于或等于今天，并且按照降序排列
  listproducts = Product.objects.filter(date_available__lt= datetime.datetime.now().date()).order_by("-date_available")

 2、上架时间大于或等于今天

  listproducts = Product.objects.filter(date_available__gt= datetime.datetime.now().date()).

3、分页

前台代码

{% if listproducts.has_previous %}
    <a href="?page={{ listproducts.previous_page_number }}">上一页</a>
{% endif %}

<span class="current">
    第 {{ listproducts.number }} 页  总共 {{ listproducts.paginator.num_pages }} 页
</span>

{% if listproducts.has_next %}
   <a href="?page={{ listproducts.next_page_number }}">下一页</a>
{% endif %}

后台代码

#购买首页
def storenew_view(request): 
    #上架时间小于或等于今天，并且按照降序排列
    listproducts = Product.objects.filter(date_available__lt= datetime.datetime.now().date()).order_by("-date_available") 
    #从session获取购物车数据
    cart = request.session.get("cart",None)
    #上架时间小于或等于今天，分页每页显示5个
    paginator = Paginator(listproducts ,5)
    try:
        page = int(request.GET.get('page', '1'))
    except ValueError:
        page = 1

    try:
        listproducts = paginator.page(page)
    except :
        listproducts = paginator.page(paginator.num_pages)
    t=get_template('depotapp/storenew.html') 
    c=RequestContext(request,locals()) 
    return HttpResponse(t.render(c)) 

 4、session应用

 cart = request.session.get("cart",None)//取值

 if not cart: //判断cart是否不存在

#必须在setting.py中加上 SESSION_SERIALIZER = 'django.contrib.sessions.serializers.PickleSerializer'
#否则会报错 <depotapp.cart.Cart object at 0x00000000036633C8> is not JSON serializable

 request.session["cart"] = cart//赋值

#清空购物车 给一个初始值
def clean_cart(request):
    request.session['cart']=Cart()
    return view_cart(request)

5、表单

 表单定义和验证

#/usr/bin/python 
#coding: utf8

from django import forms
from models import *
import itertools

def anyTrue(predicate, sequence):
    return True in itertools.imap(predicate, sequence)
def endsWith(s, *endings):
    return anyTrue(s.endswith, endings)

class ProductForm(forms.ModelForm):
    
    class Meta:
        model = Product
        # exclude = [] # uncomment this line and specify any field to exclude it from the form

    def __init__(self, *args, **kwargs):
        super(ProductForm, self).__init__(*args, **kwargs)
    
    def clean_price(self):
        price = self.cleaned_data['price']
        if price<=0:
            raise forms.ValidationError("价格必须大于零")
        return price
    def clean_image_url(self):
        url = self.cleaned_data['image_url']
        if not endsWith(url, '.jpg', '.png', '.gif'):
            raise forms.ValidationError('图片格式必须为jpg、png或gif')
        return url

<table>
<form action="" method="POST"> {% csrf_token %}
  {{form}}
  <tr>
    <td colspan="2" align="right"><input type="submit" value="Create"/></td>
  </tr>
</form>
</table>
<p><a href="{% url 'depotapp.views.list_product'%}">返回首页</a></p>

 

#创建产品
def create_product(request):
    form = ProductForm(request.POST or None)
    if form.is_valid():
        form.save()
        form = ProductForm()

    t = get_template('depotapp/create_product.html')
    c = RequestContext(request,locals())
    return HttpResponse(t.render(c))

编辑表单

def edit_product(request, id):

    product_instance = Product.objects.get(id=id)

    form = ProductForm(request.POST or None, instance = product_instance)

    if form.is_valid():
        form.save()

    t=get_template('depotapp/edit_product.html')
    c=RequestContext(request,locals())
    return HttpResponse(t.render(c))

提交成功后跳转到**页面

@transaction.commit_on_success
def create_order(request):
    form = OrderForm(request.POST or None)
    if form.is_valid():
        order = form.save()
        for item in request.session['cart'].items:
            item.order = order
            item.save()
        clean_cart(request)
        return view_order(request,int(item.order.id))

    t = get_template('depotapp/create_order.html')
    c = RequestContext(request,locals())
    return HttpResponse(t.render(c))

 

6、一些查询语句

list_items = Product.objects.all()//查询所有

product_instance = Product.objects.get(id = id)//查询id为id的数据