HTML5 AppCache: Can somebody explain purpose of NETWORK section in manifest file?

0
votes

I have gone through html5rocks, mozilla developer doc. Those definitions are very confusing. Can anybody explain this in simple terms ?

I am not sure why do we even need NETWORK section in appcache manifest file. I think it is as good as not having entry in CACHE section.

NETWORK Mozilla:

Files listed under the NETWORK: section header in the cache manifest file are white-listed resources that require a connection to the server. All requests to such resources bypass the cache, even if the user is offline. The wildcard character * can be used once. Most sites need *.

NETWORK HTML5Rocks:

Files listed in this section may come from the network if they aren't in the cache, otherwise the network isn't used, even if the user is online. You can white-list specific URLs here, or simply "", which allows all URLs. Most sites need "".

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htmlcachinghtml5-appcachecache-manifest

1 Answers

2
votes

NETWORK: are resources that requires the user to be online.

From http://www.html5rocks.com/en/tutorials/appcache/beginner/

NETWORK:

Files listed in this section may come from the network if they aren't in the cache, otherwise the network isn't used, even if the user is online. You can white-list specific URLs here, or simply "*", which allows all URLs. Most sites need "*".

General practice is to define what resources should be cached using the CACHE section, and then use NETWORK section with * wildcard to default all other resources to require the user to be online.

Example:

 CACHE:
 # These resources will be downloaded once to be cached  on the client.
 # After they are cached, even if the user has a network connection,
 # they will not re-download these resources, but instead use their local
 # cached copies instead.

 /favicon.ico
 /index.html
 /images/banner.html

 # This section will explicitly tell the client "every other resource"
 # requires a network connection.
 NETWORK:
 *

So why would you explicitly tell the client that every other resource requires a network connection?

http://alistapart.com/article/application-cache-is-a-douchebag#section7 Gotcha #5 will explain that.

If you cache index.html but not cat.jpg, that image will not display on index.html even if you’re online.

And you can see their demo here: http://appcache-demo.s3-website-us-east-1.amazonaws.com/without-network/