Cache Filter
The Cache Filter provides client side caching support for the HTTP protocol.
The cache is as much as possible HTTP/1.1 compliant and can be used either
by standalone browsers,or by a proxy (the typical case when you use
Jigsaw).
When this filter is used throughout Jigsaw proxy, it is best (ie read
recommended) to use the appropriate resources to configure it (instead
of setting manually the properties). In that case, the
CacheProp resource.
Properties
The
CacheFilter
defines the following properties:
w3c.www.protocol.http.cache.size
-
semantics
-
The size of the cache, expressed in bytes.
-
type
-
An integer property
-
default value
-
This property defaults to 5000000 bytes, ie 5Mb
w3c.www.protocol.http.cache.debug
-
semantics
-
Will make the CacheFIlter emit some (hopefully) usefull traces.
-
type
-
A boolean property
-
default value
-
This property defaults to false.
w3c.www.protocol.http.cache.shared
-
semantics
-
Is this cached shared among several users ? Some of HTTP/1.1 caching semantics
depends on wether the cache is shared or not, this flag will change the caching
policy accordingly.
-
type
-
A boolean property.
-
default value
-
This property defaults to false.
w3c.www.protocol.http.cache.directory
-
semantics
-
The directory that the cache should use to store cached content. If not provided
the directory defaults to the
.web_cache
under the current user's
home directory. Note that when used through Jigsaw the cache directory
will automatically be set to config/cache
where
config
is the main Jigsaw configuration repository.
-
type
-
A File property (should provide the path of a directory in the file system)
-
default value
-
See above.
w3c.www.protocol.http.cache.connected
-
semantics
-
Should the cache consider itself connected to the Internet ? The cache filter
can be used in disconnected mode, in which case it will only look
for document in the cache, and if not found, will emit the appropriate HTTP/1.1
error reply.
You may experience funny results when disconnecting the cache from the Internet,
most of them are the results of content providers not providing the appropriate
informations (and some time, even intentionnaly).
-
type
-
A boolean property
-
default value
-
This property defaults to true.
w3c.www.protocol.http.cache.garbageCollectionEnabled
-
semantics
-
Should the cache try to run its garbage collector ? This flag is intended
to be used when the user's is planning to disconnect the cache. By setting
the flag to false, he/she can safely browse the web and everything
he/she visits will enter the cache (for latter consumption) and stay
there.
An interesting project, of course, would be to write a robot to fill the
cache automatically (stay tuned, or write it !)
-
type
-
A boolean property
-
default value
-
This property defaults to true.
w3c.www.protocol.http.cache.fileSizeRatio
-
semantics
-
The ratio to the total cache size that a single entry in the cache is allowed
to occupy.
-
type
-
A double property (a ratio between 0 and 1 indicating how much
of the total cache space a single cached entry is able to occupy).
-
default value
-
This property defaults to 0.1 (which means that if you are using the
default cache size of 5Mb,
only file smaller than 500Kb are candidate to enter the cache)
Jigsaw Team
$Id: w3c.www.protocol.http.cache.CacheFilter.html,v 1.2 1997/07/31 08:25:42 ylafon Exp $