52 lines
2.3 KiB
Python
52 lines
2.3 KiB
Python
import logging
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import time
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from django.http import HttpResponse, Http404, HttpResponseNotModified
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from xmodule.contentstore.django import contentstore
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from xmodule.contentstore.content import StaticContent, XASSET_LOCATION_TAG
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from cache_toolbox.core import get_cached_content, set_cached_content
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from xmodule.exceptions import NotFoundError
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class StaticContentServer(object):
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def process_request(self, request):
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# look to see if the request is prefixed with 'c4x' tag
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if request.path.startswith('/' + XASSET_LOCATION_TAG + '/'):
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loc = StaticContent.get_location_from_path(request.path)
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# first look in our cache so we don't have to round-trip to the DB
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content = get_cached_content(loc)
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if content is None:
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# nope, not in cache, let's fetch from DB
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try:
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content = contentstore().find(loc)
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except NotFoundError:
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response = HttpResponse()
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response.status_code = 404
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return response
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# since we fetched it from DB, let's cache it going forward
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set_cached_content(content)
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else:
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# @todo: we probably want to have 'cache hit' counters so we can
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# measure the efficacy of our caches
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pass
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# see if the last-modified at hasn't changed, if not return a 302 (Not Modified)
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# convert over the DB persistent last modified timestamp to a HTTP compatible
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# timestamp, so we can simply compare the strings
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last_modified_at_str = content.last_modified_at.strftime("%a, %d-%b-%Y %H:%M:%S GMT")
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# see if the client has cached this content, if so then compare the
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# timestamps, if they are the same then just return a 304 (Not Modified)
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if 'HTTP_IF_MODIFIED_SINCE' in request.META:
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if_modified_since = request.META['HTTP_IF_MODIFIED_SINCE']
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if if_modified_since == last_modified_at_str:
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return HttpResponseNotModified()
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response = HttpResponse(content.data, content_type=content.content_type)
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response['Last-Modified'] = last_modified_at_str
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return response
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