Django 实现图片上传和下载功能

#新建工程 
python manage.py startapp test30
#修改 settings.py
INSTALLED_APPS = [
  'django.contrib.admin',
  'django.contrib.auth',
  'django.contrib.contenttypes',
  'django.contrib.sessions',
  'django.contrib.messages',
  'django.contrib.staticfiles',
  'stu'
]
#修改urls.py
from django.conf.urls import url, include
from django.contrib import admin

urlpatterns = [
  url(r'^admin/', admin.site.urls),
  url(r'student/',include('stu.urls')),
]
#新增加 stu/urls.py 
#coding:utf-8
from django.conf.urls import url
import views
urlpatterns = [
  url(r'^$',views.index_view)
]
#编辑 stu/views.py 
# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.http import HttpResponse
from django.shortcuts import render

# Create your views here.
#原生上传文件方式
def index_view(request):
  if request.method == 'GET':
    return render(request,'index.html')
  elif request.method == 'POST':
    #获取请求参数
    uname = request.POST.get('uname','')
    photo = request.FILES.get('photo','')
    print photo.name
    import os
    print os.getcwd()
    if not os.path.exists('media'):
       os.mkdir('media')
    #拼接路径
    with open(os.path.join(os.getcwd(),'media',photo.name),'wb') as fw:
      # photo.read() #一次性读取文件到内存
      # fw.write(photo.read())

      #分块读取，性能高
      for ck in photo.chunks():
        fw.write(ck)

    return HttpResponse('It is post request,上传成功')

  else:
    return HttpResponse('It is not post and get request!')
#新增加模板文件 templates/index.html



  
  



  {% csrf_token %}
  

    姓名:  
  
  

    头像:  
  
  

         
  



#效果如下:
访问: http://127.0.0.1:8000/student/

需求：
效果: 访问 http://127.0.0.1:8000/student/ 通过注册将姓名、头像地址传入数据库中；
访问 http://127.0.0.1:8000/student/showall 将数据库信息通过表格形式展示

###过程
#修改 settings.py ，templates 新增加 'django.template.context_processors.media'
TEMPLATES = [
  {
    'BACKEND': 'django.template.backends.django.DjangoTemplates',
    'DIRS': [os.path.join(BASE_DIR, 'templates')]
    ,
    'APP_DIRS': True,
    'OPTIONS': {
      'context_processors': [
        'django.template.context_processors.debug',
        'django.template.context_processors.request',
        'django.contrib.auth.context_processors.auth',
        'django.contrib.messages.context_processors.messages',
        'django.template.context_processors.media'
      ],
    },
  },
]

末尾增加：
# global_settings
#指定上传文件存储相对路径（读取文件）
MEDIA_URL = '/media/'
#指定上传文件存储绝对路径（存储文件）
MEDIA_ROOT = os.path.join(BASE_DIR,'media')

#创建数据库模型 stu/models.py
# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.db import models

# Create your models here.

class Student(models.Model):
  sno = models.AutoField(primary_key=True)
  sname = models.CharField(max_length=30)
  photo = models.ImageField(upload_to='imgs')

  def __unicode__(self):
    return u'Student:%s'%self.sname
#生成数据库迁移文件,查看数据库表结构
python makemigrations stu
python migrate 


#修改 urls.py 因为显示问题，增加 DEBUG 内容
from django.conf.urls import url, include
from django.contrib import admin

from test30.settings import DEBUG, MEDIA_ROOT

urlpatterns = [
  url(r'^admin/', admin.site.urls),
  url(r'student/',include('stu.urls')),
]
from django.views.static import serve
if DEBUG:
  urlpatterns+=url(r'^media/(?P.*)/$', serve, {"document_root": MEDIA_ROOT}),

#修改 urls， stu/urls.py
#coding:utf-8
from django.conf.urls import url
import views
urlpatterns = [
  url(r'^$',views.index_view),
  url(r'^upload/$',views.upload_view),
  url(r'^showall/$',views.showall_view)
]

# 修改 stu/views.py
#django 上传文件方式
def upload_view(request):
  uname = request.POST.get('uname','')
  photo = request.FILES.get('photo','')
  #入库操作
  Student.objects.create(sname=uname,photo=photo)
  return HttpResponse('上传成功!')

#显示图片
def showall_view(request):
  stus = Student.objects.all()
  print stus
  return render(request,'show.html',{'stus':stus})

# 修改 index.html



  
  



  {% csrf_token %}
  

    姓名:  
  
  

    头像:  
  
  

         
  



# 增加模板文件 show.html



  
  



  {% for stu in stus %}
  
  {% endfor %}


  

    
编号
    
姓名
    
头像
    
操作
  

  
{{ forloop.counter }}
  
{{ stu.sname }}
  

  
 下载
  


效果图：
http://127.0.0.1:8000/student/ 注册实现数据库录入操作(点击提交通过index.html 中action="/student/upload/" 将url 转发至函数upload_view ，实现上传功能)
http://127.0.0.1:8000/student/showall/ 实现数据库信息展示

### 需求
在显示页面点击下载实现图片的下载功能
过程：

#修改 show.html ，加入 下载的超链接



  
  



  {% for stu in stus %}
  
  {% endfor %}


  

    
编号
    
姓名
    
头像
    
操作
  

  
{{ forloop.counter }}
  
{{ stu.sname }}
  

  
下载
  




#因为 show.html href="/student/download ，所以要修改urls
#修改 stu/urls.py,新增加 url
url(r'^download/$',views.download_view)

#修改 stu/views.py

def download_view(request):
  # 获取请求参数（图片存储位置） imgs/5566.jpg
  photo = request.GET.get('photo','')
  print photo

  # 获取图片文件名5566.jpg ; rindex 为字符 '/' 在 photo 中最后出现的位置索引；例如
  # txt = "imgs/5566.jpg"
  # x = txt.rindex("/")
  # print txt[x + 1:]  输出结果为 5566.jpg
  filename = photo[photo.rindex('/')+1:]
  print filename
  #开启一个流
  import os
  path = os.path.join(os.getcwd(),'media',photo.replace('/','\\'))
  print path

  with open(path,'rb') as fr:
    response = HttpResponse(fr.read())
    response['Content-Type']='image/png'
    response['Content-Disposition'] = 'attachment;filename=' + filename

  return response

#访问 http://127.0.0.1:8000/student/showall/ ，点击下载