在浏览器中缓存图片 - app-engine-patch应用程序 [英] Images caching in browser - app-engine-patch application

问题描述

我在浏览器中为应用程序引擎应用程序缓存图像时遇到了一些问题
我发送最后修改的，到期的和缓存控制标题，但每次都从服务器加载图像。
以下是代码的标题部分：

response ['Content-Type'] ='image / jpg'

response ['Last-Modified'] = current_time.strftime（'％a，％d％b％Y％H：％M：％S GMT'）

response ['Expires'] = current_time + timedelta（days = 30）
$ b response ['Cache-Control'] ='public，max- age = 2592000'

解决方案

以下是我在dpaste中修复副本的示例代码 here

  def view_image（request，key ）：
 data = memcache.get（key）
如果数据不是无：
 if（request.META.get（'HTTP_IF_MODIFIED_SINCE'）> = data ['Last-Modified' ]）：
 data.status_code = 304 
返回数据
 else：
 image_content_blob = #some代码从数据存储中获取图像
 current_time = datetime.utcnow （）
 response = HttpResponse（）
 last_modified = current_time  -  timedelta（days = 1）
 response ['Content-Type'] ='image / jpg'
 response ['Last-Modified'] = last_modified.strftime（'％a，％ d'b％Y％H：％M：％S GMT'）
 response ['Expires'] = current_time + timedelta（days = 30）
 response ['Cache-Control'] ='public ，max-age = 315360000'
 response ['Date'] = current_time 
 response.content = image_content_blob 
 
 memcache.add（image_key，response，86400）
返回响应
  

I have a little problem with caching the images in the browser for my app-engine application I`m sending last-modified, expires and cache-control headers but image is loaded from the server every time. Here is the header part of the code:

response['Content-Type'] = 'image/jpg'

response['Last-Modified'] = current_time.strftime('%a, %d %b %Y %H:%M:%S GMT')

response['Expires'] = current_time + timedelta(days=30)

response['Cache-Control'] = 'public, max-age=2592000'

解决方案

Here is an example code for my fix copy in dpaste here

def view_image(request, key):
  data = memcache.get(key)  
  if data is not None:  
    if(request.META.get('HTTP_IF_MODIFIED_SINCE') >= data['Last-Modified']):  
      data.status_code = 304  
    return data  
  else:  
    image_content_blob = #some code to get the image from the data store  
    current_time = datetime.utcnow()
    response = HttpResponse()
    last_modified = current_time - timedelta(days=1)
    response['Content-Type'] = 'image/jpg'
    response['Last-Modified'] = last_modified.strftime('%a, %d %b %Y %H:%M:%S GMT')
    response['Expires'] = current_time + timedelta(days=30)
    response['Cache-Control']  = 'public, max-age=315360000'
    response['Date']           = current_time
    response.content = image_content_blob

    memcache.add(image_key, response, 86400)
    return response

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