Python Web开发：开发资料下载功能
来自CloudWiki
创建“资料”模型
对资料建模，在数据库中创建对应资料类Doc
serviceApp/models.py:
from django.db import models
import django.utils.timezone as timezone
# Create your models here.
class Doc(models.Model):
title = models.CharField(max_length=250, verbose_name='资料名称')
file = models.FileField(upload_to='Service/',
blank=True,
verbose_name='文件资料')
publishDate = models.DateTimeField(max_length=20,
default=timezone.now,
verbose_name='发布时间')
def __str__(self):
return self.title
class Meta:
ordering = ['-publishDate']
verbose_name = "资料"
verbose_name_plural = verbose_name
- 通过参数upload_to的设置使得上传的文件统一放置在media/Service文件夹下面
python manage.py makemigrations
Migrations for 'contactApp':
contactApp\migrations\0003_auto_20210531_2203.py
- Alter field birth on resume
Migrations for 'serviceApp':
serviceApp\migrations\0001_initial.py
- Create model Doc
python manage.py migrate
Operations to perform: Apply all migrations: aboutApp, admin, auth, contactApp, contenttypes, newsApp, productsApp, serviceApp, sessions Running migrations: Applying contactApp.0003_auto_20210531_2203... OK Applying serviceApp.0001_initial... OK
注册模型
serviceApp/admin.py:
from django.contrib import admin # Register your models here. from .models import Doc admin.site.register(Doc)
保存后启动项目，登录后台系统，找到”资料“模型，添加几条暑假：
注意：上传的文件资料路径中不能含有中文。
”资料下载列表“页面开发
serviceApp/templates/ 下新建模板文件docList.html：
{% extends "base.html" %}
{% load staticfiles %}
{% block title %}
资料下载
{% endblock %}
{% block content %}
<link href="{% static 'css/news.css' %}" rel="stylesheet">
<!-- 广告横幅 -->
<div class="container-fluid">
<div class="row">
<img class="img-responsive model-img" src="{% static 'img/service.jpg' %}">
</div>
</div>
<!-- 主体内容 -->
<div class="container">
<div class="row row-3">
<!-- 侧边导航栏 -->
<div class="col-md-3">
<div class="model-title">
服务支持
</div>
<div class="model-list">
<ul class="list-group">
<li class="list-group-item" id='download'>
<a href="{% url 'serviceApp:download' %}">资料下载</a>
</li>
<li class="list-group-item" id='platform'>
<a href="{% url 'serviceApp:platform' %}">人脸识别开放平台</a>
</li>
</ul>
</div>
</div>
<!-- 说明文字和图片 -->
<div class="col-md-9">
<div class="model-details-title">
资料列表
</div>
<div class="model-details">
{% for doc in docList %}
<div class="news-model">
<img src="{% static 'img/newsicon.gif' %}">
<a href="{% url 'serviceApp:getDoc' doc.id %}"><b>{{doc.title}}</b></a>
<span>【{{doc.publishDate|date:"Y-m-d"}}】</span>
</div>
{% endfor %}
{% if pageData %}
<div class="paging">
<ul id="pages" class="pagination">
{% if pageData.first %}
<li><a href="?page=1">1</a></li>
{% endif %}
{% if pageData.left %}
{% if pageData.left_has_more %}
<li><span>...</span></li>
{% endif %}
{% for i in pageData.left %}
<li><a href="?page={{i}}">{{i}}</a></li>
{% endfor %}
{% endif %}
<li class="active"><a href="?page={{pageData.page}}">
{{pageData.page}}</a></li>
{% if pageData.right %}
{% for i in pageData.right %}
<li><a href="?page={{i}}">{{i}}</a></li>
{% endfor %}
{% if pageData.right_has_more %}
<li><span>...</span></li>
{% endif %}
{% endif %}
{% if pageData.last %}
<li><a href="?page={{pageData.total_pages}}">
{{pageData.total_pages}}</a></li>
{% endif %}
</ul>
</div>
{% endif %}
</div>
</div>
</div>
</div>
{% endblock %}
注：资料访问路由 由{% url 'serviceApp:getDoc' doc.id%}设置，
添加路由
serviceApp /urls.py 添加路由：
from django.urls import path
from . import views
app_name = 'serviceApp'
urlpatterns = [
path('download/', views.download, name='download'), # 资料下载
path('platform/', views.platform, name='platform'), # 人脸识别开放平台
path('getDoc/<int:id>/',views.getDoc,name='getDoc'),
]
修改视图函数
修改download函数
传入docList变量，具体和newsApp下的news()函数基本一致。
from django.shortcuts import render
from django.shortcuts import HttpResponse
from .models import Doc
from django.core.paginator import Paginator
def download(request):
submenu = 'download'
docList = Doc.objects.all().order_by('-publishDate')
p = Paginator(docList, 5)
if p.num_pages <= 1:
pageData = ''
else:
page = int(request.GET.get('page', 1))
newList = p.page(page)
left = []
right = []
left_has_more = False
right_has_more = False
first = False
last = False
total_pages = p.num_pages
page_range = p.page_range
if page == 1:
right = page_range[page:page + 2]
print(total_pages)
if right[-1] < total_pages - 1:
right_has_more = True
if right[-1] < total_pages:
last = True
elif page == total_pages:
left = page_range[(page - 3) if (page - 3) > 0 else 0:page - 1]
if left[0] > 2:
left_has_more = True
if left[0] > 1:
first = True
else:
left = page_range[(page - 3) if (page - 3) > 0 else 0:page - 1]
right = page_range[page:page + 2]
if left[0] > 2:
left_has_more = True
if left[0] > 1:
first = True
if right[-1] < total_pages - 1:
right_has_more = True
if right[-1] < total_pages:
last = True
pageData = {
'left': left,
'right': right,
'left_has_more': left_has_more,
'right_has_more': right_has_more,
'first': first,
'last': last,
'total_pages': total_pages,
'page': page,
}
return render(
request, 'docList.html', {
'active_menu': 'service',
'sub_menu': submenu,
'docList': docList,
'pageData': pageData,
})
修改getDoc()函数
文件下载，普通的HttpResponse可以用，
但是Django提供了专门的StreamingHttpResponse对象来代替HttpResponse
具体的，在views.py 中添加一个文件分批读取的函数read_file(),
该函数通过构建一个迭代器，分批处理文件。
# Create your views here.
def read_file(file_name, size): #分批读取文件
with open(file_name, mode='rb') as fp:
while True:
c = fp.read(size)
if c:
yield c
else:
break
其中file_name为文件路径，size为分批读取文件的大小。
修改getDoc()函数:
from django.shortcuts import get_object_or_404
from django.http import StreamingHttpResponse
import os
def getDoc(request, id):
doc = get_object_or_404(Doc, id=id)
update_to, filename = str(doc.file).split('/')
filepath = '%s/media/%s/%s' % (os.getcwd(), update_to, filename)
response = StreamingHttpResponse(read_file(filepath, 512))
response['Content-Type'] = 'application/octet-stream'
response['Content-Disposition'] = 'attachment;filename="{}"'.format(
filename)
return response
- 获取文件：get_object_or_404
- 读取文件：read_file()
- 设置文件类型：为了防止文件以乱码形式显示到浏览器上，而非下载到硬盘上：
response['Content-Type'] = 'application/octet-stream'
response['Content-Disposition'] = 'attachment;filename="{}"'.format(
filename)
保存所有修改后启动项目，打开”资料下载“页面 进行下载：
