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# -*- coding: utf-8 -*- |
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""" |
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Utility functions to help with range handling. |
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.. versionadded:: 0.1.0 |
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""" |
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import re |
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MAX_NUMBER_ITEMS = 5000 |
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def parse_range_header(range): |
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""" |
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Parse a range header as used by the dojo Json Rest store. |
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:param str range: The content of the range header to be parsed. |
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eg. `items=0-9` |
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:returns: A dict with keys start, finish and number or `False` if the |
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range is invalid. |
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""" |
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match = re.match('^items=([0-9]+)-([0-9]+)$', range) |
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if match: |
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start = int(match.group(1)) |
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finish = int(match.group(2)) |
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if finish < start: |
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finish = start |
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return { |
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'start': start, |
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'finish': finish, |
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'count': finish - start + 1 |
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} |
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else: |
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return False |
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def range_return(request, items): |
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""" |
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Determine what range of objects to return. |
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Will check fot both `Range` and `X-Range` headers in the request and |
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set both `Content-Range` and 'X-Content-Range' headers. |
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:rtype: list |
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""" |
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if ('Range' in request.headers): |
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range = parse_range_header(request.headers['Range']) |
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elif 'X-Range' in request.headers: |
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range = parse_range_header(request.headers['X-Range']) |
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else: |
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range = { |
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'start': 0, |
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'finish': MAX_NUMBER_ITEMS - 1, |
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'count': MAX_NUMBER_ITEMS |
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} |
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filtered = items[range['start']:range['finish'] + 1] |
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if len(filtered) < range['count']: |
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# Something was stripped, deal with it |
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range['count'] = len(filtered) |
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range['finish'] = range['start'] + range['count'] - 1 |
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if range['finish'] - range['start'] + 1 >= MAX_NUMBER_ITEMS: |
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range['finish'] = range['start'] + MAX_NUMBER_ITEMS - 1 |
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filtered = items[range['start']:range['finish'] + 1] |
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request.response.headers['Content-Range'] = 'items %d-%d/%d' % (range['start'], range['finish'], len(items)) |
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request.response.headers['X-Content-Range'] = request.response.headers['Content-Range'] |
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return filtered |
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def set_http_caching(request, gateway='crab', region='permanent'): |
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""" |
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Set an HTTP Cache Control header on a request. |
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:param pyramid.request.Request request: Request to set headers on. |
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:param str gateway: What gateway are we caching for? Defaults to `crab`. |
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:param str region: What caching region to use? Defaults to `permanent`. |
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:rtype: pyramid.request.Request |
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""" |
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crabpy_exp = request.registry.settings.get('crabpy.%s.cache_config.%s.expiration_time' % (gateway, region), None) |
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if crabpy_exp is None: |
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return request |
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ctime = int(int(crabpy_exp) * 1.05) |
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request.response.cache_expires(ctime, public=True) |
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return request |
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OnroerendErfgoed /
crabpy_pyramid
