[Httplib2-discuss] Bug #1459543: headers={'cache-control':'only-if-cached'}

[Thomas B. <t.b...@gm...>]

I think this could be solved in many ways:
 - either line 606, by initializing "info" to a "Status: 504" message,
but we must then make sure this message doesn't have an "etag", or
other things that could break "cache freshness" computation
 - or line 647, looking for an empty "info" (or an "info" lacking a
"status", or catching the KeyError, or =96better=96 looking for an empty
cacheFullPath) and then returning a "Status: 504" message
 - or line 721, using int(self.get('status', 504)) instead of
int(self['status']) --or catching the KeyError exception and then
defaulting to a "Status: 504" message.

I'd rather go for the second choice, replacing lines 646 to 649 with
something like:
                if entry_disposition =3D=3D "FRESH":
                    if not os.path.exists(cacheFullPath):
                        # This should be the case only for a
"Cache-Control: only-if-cached" request
                        return CACHED_VERSION_UNAVAILABLE
                    else:
                        response =3D Response(info)
                        response.fromcache =3D True
                        return (response, content)

after having defined a global variable:
CACHED_VERSION_UNAVAILABLE =3D (
    Response(rfc822.Message(StringIO.StringIO("""\
Status: 504
Content-Type: text/plain
""")),
    "You asked for a cached version only, and no cached version is availabl=
e."
)

--
Thomas Broyer