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This will save you a *lot* of time in subsequent sessions, because
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you'll be able to use cached versions of the initial (very expensive)
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documents. A new client will not re-request the service root at all.
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>>> second_service = CookbookWebServiceClient(cache=unicode(tempdir))
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You'll also be able to make conditional requests for many resources
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and avoid transferring their full representations.
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>>> print second_service.recipes[4].instructions
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send: 'GET /1.0/recipes/4 ...
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Of course, if you ever need to clear the cache directory, you'll have
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to do it yourself.
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>>> shutil.rmtree(tempdir)
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The '1.0' version of the example web service, which we've been using up til
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now, sets a long cache expiry time for the service root. That's why we
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were able to create a second client that didn't request the service
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root at all--just fetched the representations from its cache.
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The 'devel' version of the example web service sets a cache expiry
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time of two seconds. Let's see what that looks like on the client side.
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>>> tempdir = tempfile.mkdtemp()
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>>> first_service = CookbookWebServiceClient(
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... cache=tempdir, version='devel')
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send: 'GET /devel/ ...
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send: 'GET /devel/ ...
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Now let's wait for three seconds to make sure the representations become
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>>> from time import sleep
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When the representations are stale, a new client makes *conditional*
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requests for the representations. If the conditions fail (as they do
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here), the cached representations are considered to have been
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refreshed, just as if the server had sent them again.
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>>> second_service = CookbookWebServiceClient(
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... cache=tempdir, version='devel')
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send: 'GET /devel/ ...
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send: 'GET /devel/ ...
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Let's quickly create another client before the representation grows
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>>> second_service = CookbookWebServiceClient(
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... cache=tempdir, version='devel')
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When the representations are not stale, a new client does not make any
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HTTP requests at all--it fetches representations direct from the
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>>> httplib2.debuglevel = 0
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>>> shutil.rmtree(tempdir)
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206
caps filenames at about 240 characters so that cache files can be
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stored on filesystems with 255-character filename length limits. For
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compatibility with eCryptfs filesystems, lazr.restfulclient goes
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further, and caps filenames at 150 characters.
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further, and caps filenames at 143 characters.
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To test out the limit, let's create a cookbook with an incredibly
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... if 'amazingly' in file]
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Indeed, the filename has been truncated to fit in the rough
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150-character safety limit for eCryptfs filesystems.
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143-character safety limit for eCryptfs filesystems.
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240
>>> len(cookbook_cache_filename)
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Despite the truncation, some of the useful information from the
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cookbook's name makes it into the filename, making it easy to find when
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... price=10.22, last_printing=date)
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This cookbook's URL is identical to the first cookbook's URL for far
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longer than 150 characters. But since the truncated filename
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longer than 143 characters. But since the truncated filename
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incorporates an MD5 sum based on the full URL, the two cookbooks are
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cached in separate files.
added
removed
src/lazr/restfulclient/docs/caching.txt
