Thank you for the reply, Mr. John and I apologize for a very late response
from my end.
* John J. Lee <[EMAIL PROTECTED]> [2007-07-06 18:53:09]:
> "O.R.Senthil Kumaran" <[EMAIL PROTECTED]> writes:
>
> > Hi,
> > There is an Open Tracker item against urllib2 library python.org/sf/735515
>
> > I am not completely getting what "cache - redirection" implies and what
> > should
> > be done with the urllib2 module. Any pointers?
>
> When a 301 redirect occurs after a request for URL U, via
> urllib2.urlopen(U), urllib2 should remember the result of that
> redirection, viz a second URL, V. Then, when another
> urllib2.urlopen(U) takes place, urllib2 should send an HTTP request
> for V, not U. urllib2 does not currently do this. (Obviously the
> cache -- that is, the dictionary or whatever that stores the mapping
> from URLs U to V -- should not be maintained by function urlopen
> itself. Perhaps it should live on the redirect handler.)
>
I spent a little time thinking about a solution and figured out that the
following changes to HTTPRedirectHandler, might be helpful in implementing
this.
Class HTTPRedirectHandler(BaseHandler):
# ... omitted ...
# Initialize a dictionary to hold cache.
def __init__(self):
self.cache = {}
# Handles 301 errors separately in a different function which maintains a
# maintains cache.
def http_error_301(self, req, fp, code, msg, headers):
if req in self.cache:
# Look for loop, if a particular url appears in both key and value
# then there is loop and return HTTPError
if len(set(self.cache.keys()) & set(self.cache.values())) > 0:
raise HTTPError(req.get_full_url(), code, self.inf_msg + msg +
headers, fp)
return self.cache[req]
self.cache[req] = self.http_error_302(req,fp,code,msg, headers)
return self.cache[req]
John, let me know your comments on this approach.
I have not tested this code in real scenario yet with a 301 redirect.
If its okay, I shall test it and submit a patch for the tracker item.
Thanks,
Senthil
--
O.R.Senthil Kumaran
http://uthcode.sarovar.org
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