day47-Django表单验证图片上传和分页技术

一、表单验证

1.定义验证表单

from django import forms


class AddArtForm(forms.Form):
    # required = True 表示必填项
    # min_length 表示最小长度
    title = forms.CharField(min_length=5, required=True)
    desc = forms.CharField(min_length=20, required=True)
    content = forms.CharField(required=True)

2.使用表单验证
is_valid()：验证参数是否有效，如果参数验证成功返回True，否则返回False
from.errors：返回错误信息

from article.Artform import AddArtForm


def add_art(request):
    if request.method == 'GET':
        return render(request, 'add_article.html')

    if request.method == 'POST':
        # 把提交的数据交给表单AddArtForm做验证
        form = AddArtForm(request.POST)

        if form.is_valid():
            title = form.cleaned_data['title']
            desc = form.cleaned_data['desc']
            content = form.cleaned_data['content']
            Article.objects.create(title=title, desc=desc, content=content)

            # 创建文章成功后，返回文章列表页面
            return HttpResponseRedirect(reverse('art:art_list'))
        else:
            # 表示字段验证失败，需要将错误信息返回给页面展示
            return render(request, 'add_article.html', {'form': form})

3.反向解析
(1)修改urls.py配置文件

from django.conf.urls import url, include
from django.contrib import admin

urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^article/', include('article.urls', namespace='art'))
]

(2)修改article.urls.py配置文件

from django.conf.urls import url

from article import views

urlpatterns = [
    # 创建文章
    url(r'^add_art/', views.add_art, name='add'),
    # 文章列表
    url(r'^art/', views.art, name='art_list'),
]

(3)url反向解析

from django.urls import reverse


def add_art(request):
    if request.method == 'GET':
        return render(request, 'add_article.html')

    if request.method == 'POST':
        form = AddArtForm(request.POST)

        if form.is_valid():
            title = form.cleaned_data['title']
            desc = form.cleaned_data['desc']
            content = form.cleaned_data['content']
            Article.objects.create(title=title, desc=desc, content=content)
            # url反向解析
            return HttpResponseRedirect(reverse('art:art_list'))
        else:
            return render(request, 'add_article.html', {'form': form})

---

二、分页技术

1.Paginator分页技术

# 1.使用Paginator分页
p = Paginator(需要分页的总数据，一页的条数)

# 2.获取指定页码
page = p.page(获取哪一页的页码)

# 3.获取当前页
page.number

# 4.获取当前有多少页
page.p.num_pages

# 5.获取一共多少条数据
page.p.count

# 6.获取页码范围
page.p.page_range

# 7.是否存在上一页
page.has_previous

# 8.是否存在下一页
page.has_next

# 9.获取上一页页码
page.previous_page_number

# 10.获取下一页页码
page.next_page_number

2.使用Paginator进行分页

from django.core.paginator import Paginator


def art(request):
    if request.method == 'GET':
        # 文章列表页面
        page_num = int(request.GET.get('page', 1))

        # 使用Paginator进行分页
        articles = Article.objects.all()
        # 将所有数据按照每一页2条数据进行切块处理
        paginator = Paginator(articles, 2)
        # 获取分页中的第几页数据
        page = paginator.page(page_num)

        return render(request, 'art.html', {'page': page})

3.使用切片进行分页

def art(request):
    if request.method == 'GET':
        # 文章列表页面
        page_num = int(request.GET.get('page', 1))
        # 使用切片完成分页
        articles = Article.objects.all()[(page-1)*2: page*2]

        return render(request, 'art.html', {'page': page})

---

三、图片上传

1.表单上传图片
注意：表单中必须有enctype="multipart/form-data"

<form action="" method="post" enctype="multipart/form-data">
        <p>图片：<input type="file" name="icon"></p>
        <input type="submit" value="提交">
</form>

2.修改setting.py配置文件
MEDIA_URL = '/media/'
MEDIA_ROOT = os.path.join(BASE_DIR, 'media')

# 媒体文件media配置
MEDIA_URL = '/media/'
MEDIA_ROOT = os.path.join(BASE_DIR, 'media')

3.在工程目录的urls.py文件中配置解析media的路由

from django.contrib.staticfiles.urls import static
from day07.settings import MEDIA_URL, MEDIA_ROOT

# 告诉Django，解析media文件夹中的静态文件
urlpatterns += static(MEDIA_URL, document_root=MEDIA_ROOT)

4.模型中定义保存图片的字段
models.ImageFiled(upload_to='article')

from django.db import models


class Article(models.Model):
    title = models.CharField(max_length=100)
    desc = models.CharField(max_length=150)
    content = models.TextField()
    icon = models.ImageField(upload_to='article', null=True)
    create_time = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = 'article'

5.定义视图函数
获取图片:request.FILES

def add_art(request):
    if request.method == 'GET':
        return render(request, 'add_article.html')

    if request.method == 'POST':
        form = AddArtForm(request.POST, request.FILES)

        if form.is_valid():
            title = form.cleaned_data['title']
            desc = form.cleaned_data['desc']
            content = form.cleaned_data['content']
            icon = form.cleaned_data['icon']
            Article.objects.create(title=title, desc=desc, content=content, icon=icon)
            return HttpResponseRedirect(reverse('art:art_list'))
        else:
            return render(request, 'add_article.html', {'form': form})

6.页面解析图片
页面解析图片<img src = "/media/{{ 图片对象.icon }}">

{% for art in page %}
    <tr>
        <td>{{ art.id }}</td>
        <td>{{ art.title }}</td>
        <td>{{ art.desc }}</td>
        <td>{{ art.content }}</td>
        <td><img src="/media/{{ art.icon }}" width=100px; height=100px></td>
    </tr>

---