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H5 cache-Manifest sample code sharing (picture and text)

黄舟Original: 2017-04-01 11:56:232436browse

In the appUpdate h5 page has always been cached Problem. By default, the app has a certain amount of space to cache the page. It will be loaded immediately after the update is started. After the app cache space is available, the update cannot be downloaded, and iOS can clear the cache space. You can only uninstall and reinstall (are u kidding me?) This is the worst case, you can change the address

##no-

cache

Note this. After a while, no-cache is added to the page.

<meta http-equiv="Cache-Control" content="no-cache">

tells the browser not to cache the page. In fact, the request is 304 when the page has not changed, and it is 200 if the page has changed, so no-cache is added. It doesn't mean that it will be downloaded again every time, but it will be downloaded again when it is updated. But the performance of different mobile phones is still different at this time. The same page is accessed and

js is modified. 4s has been updated, but 6sp is still the same. What to do, because there is still a cache on the server. First set the nginx cache:

 location / {
           root   html;           expires -1;
           index  index.html index.htm;
        }

and need to restart nginx:

nginx -s reload

At this time, 6sp is also updated.

But always restarting nginx is not a solution, it may cause some requests to be lost, and in this case, it is completely unusable when the network is disconnected. The

picture of the exclamation mark and the character's avatar cannot be displayed. Of course, this problem can be solved by converting it to the base64 string . Base64 is very long and takes up space wherever it is placed. , manif

no-cache+update file name+update address to be tested

manifest

You can read the introduction first w3shool: www.w3school.com.cn/html5/html_5_app_cache.asp, here is the usage situation

1. Set up html

<html manifest="index.appcache">

2. Set up the cache directory

CACHE MANIFEST
#v1.0.0.0#需要缓存的文件js/zepto.js#不需要缓存的页面
NETWORK:*#无法访问页面
FALLBACK404.html

3. Set nginx mime

text/cache-manifest         appcache;

The mime types files are all in the conf directory. After starting nginx, the page will load:

This picture illustrates two things. One is that index.appcache will be downloaded first in the process, and then checking event, download event, progress event and up

date

Ready event will be triggered successively. The second one is that it is cached by default. The current page. And it actually takes a parameter and caches it. It seems that as long as the current pages with different addresses are cached (I only wrote one zepto in the cache directory above). Refresh the page again:

If index.appcache is not updated, the check will not be triggered.

Loading cached files

Status

is 200, and the size column is from cache. The one loaded from the browser is 304, one is a few milliseconds, and the other is more than ten milliseconds. F12 enters developer mode, and you can see the cached files in the Application cache column.

But it cannot be cleaned in this place. It needs to be cleaned in

clear

storage in Application.

Update cached files

The most obvious one is the homepage, which is cached by default. At this time, it will have no effect if you change the content of the homepage without modifying index.appache. For example, if you delete the

reference

of a js, the client still downloads the js. At this time, you need to modify this cache file:

#不需要缓存的页面
NETWORK:  
mobile/index.html
*

Notice that although index.appache and index are at the same level, index.html cannot be written, and the path equivalent to the website must be written. The same is true for other resources. At this time, the update is triggered, but the page is still loaded with cached resources, so another process needs to be done:

  window.applicationCache.addEventListener("updateready", function(){
    location.reload()
  });

这样才会加载最新的页面。如果首页再发生修改，可以随意(加个空格，加空行)修改缓存文件，就能触发更新。所以剩下的问题就是记得在更新资源之后记得更新缓存文件。建议就是不变的资源(框架样式，框架js，图片)缓存下来，经常要修改的js就让浏览器缓存吧。现在这样就避免了reload nginx。这个效果要比加no-cache的方法好。当然，如果无所谓消息或者reload的影响。no-cache还是很方便，毕竟这个index.appache一旦加上，难以去掉，除非清理缓存。

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