--- a/app/soc/views/helper/lists.py Fri May 15 12:37:01 2009 +0200
+++ b/app/soc/views/helper/lists.py Sun Apr 12 09:06:45 2009 +0000
@@ -22,7 +22,6 @@
'"Pawel Solyga" <pawel.solyga@gmail.com>',
]
-import logging
from soc.logic import dicts
from soc.logic.models.user import logic as user_logic
@@ -61,6 +60,8 @@
OFFSET_KEY = 'offset_%d'
LIMIT_KEY = 'limit_%d'
+OFFSET_LINKID_KEY = 'offset_linkid_%d'
+REVERSE_DIRECTION_KEY = 'reverse_sort_direction_%d'
def makeOffsetKey(limit_idx):
@@ -71,6 +72,14 @@
return LIMIT_KEY % limit_idx
+def makeOffsetLinkidKey(limit_idx):
+ return OFFSET_LINKID_KEY % limit_idx
+
+
+def makeReverseDirectionKey(limit_idx):
+ return REVERSE_DIRECTION_KEY % limit_idx
+
+
def getListParameters(request, list_index):
"""Retrieves, converts and validates values for one list
@@ -110,30 +119,44 @@
else:
limit = min(DEF_MAX_PAGINATION, limit)
- return dict(limit=limit, offset=offset)
+ result = dict(limit=limit, offset=offset)
+ offset_linkid = request.GET.get(makeOffsetLinkidKey(list_index),
+ '')
+ # TODO(dbentley): URL unescape
+ result['offset_linkid'] = offset_linkid
+
+ reverse_direction = makeReverseDirectionKey(list_index) in request.GET
+ result['reverse_direction'] = reverse_direction
+
+ return result
-def generateLinkFromGetArgs(request, offset_and_limits):
- """Constructs the get args for the url.
+class LinkCreator(object):
+ """A way to create links for a page.
"""
-
- args = ["%s=%s" % (k, v) for k, v in offset_and_limits.iteritems()]
- link_suffix = '?' + '&'.join(args)
-
- return request.path + link_suffix
-
+ def __init__(self, request, list_idx, limit):
+ self.path = request.path
+ self.base_params = dict(
+ i for i in request.GET.iteritems() if
+ i[0].startswith('offset_') or i[0].startswith('limit_'))
+ self.idx = list_idx
+ self.base_params[makeLimitKey(self.idx)] = limit
-def generateLinkForRequest(request, base_params, updated_params):
- """Create a link to the same page as request but with different params
-
- Params:
- request: the request for the page
- base_params: the base parameters
- updated_params: the parameters to update
- """
- params = base_params.copy()
- params.update(updated_params)
- return generateLinkFromGetArgs(request, params)
+ def create(self, offset_linkid=None, export=False, reverse_direction=False):
+ params = self.base_params.copy()
+ if offset_linkid is not None:
+ # TODO(dbentley): URL encode
+ if offset_linkid == '':
+ try:
+ del params[makeOffsetLinkidKey(self.idx)]
+ except KeyError:
+ pass
+ else:
+ params[makeOffsetLinkidKey(self.idx)]=offset_linkid
+ if reverse_direction:
+ params[makeReverseDirectionKey(self.idx)]=True
+ link_suffix = '&'.join('%s=%s' % (k, v) for k, v in params.iteritems())
+ return '%s?%s' % (self.path, link_suffix)
def getListContent(request, params, filter=None, order=None,
@@ -174,13 +197,36 @@
# as we only use this logic for getForFields, which is never overridden
logic = params['logic']
- limit_key, offset_key = makeLimitKey(idx), makeOffsetKey(idx)
+ limit_key = makeLimitKey(idx)
+ # offset_key = makeOffsetKey(idx)
+ # offset_linkid_key = makeOffsetLinkidKey(idx)
+ # reverse_direction_key = makeReverseDirectionKey(idx)
list_params = getListParameters(request, idx)
limit, offset = list_params['limit'], list_params['offset']
+ offset_linkid = list_params['offset_linkid']
+ reverse_direction = list_params['reverse_direction']
pagination_form = makePaginationForm(request, list_params['limit'],
limit_key)
+ if offset_linkid:
+ if filter is None:
+ filter = {}
+
+ if reverse_direction:
+ filter['link_id <'] = offset_linkid
+ else:
+ filter['link_id >'] = offset_linkid
+
+ if order is None:
+ order = []
+ if reverse_direction:
+ order.append('-link_id')
+ else:
+ order.append('link_id')
+
+
+
# Fetch one more to see if there should be a 'next' link
data = logic.getForFields(filter=filter, limit=limit+1, offset=offset,
order=order)
@@ -189,46 +235,61 @@
return None
more = len(data) > limit
-
- if more:
- del data[limit:]
-
- newest = next = prev = export_link = ''
-
- base_params = dict(i for i in request.GET.iteritems() if
- i[0].startswith('offset_') or i[0].startswith('limit_'))
-
- if params.get('list_key_order'):
- export_link = generateLinkForRequest(request, base_params, {'export' : idx})
+ if reverse_direction:
+ data.reverse()
if more:
- # TODO(dbentley): here we need to implement a new field "last_key"
- next = generateLinkForRequest(request, base_params, {offset_key : offset+limit,
- limit_key : limit})
+ if reverse_direction:
+ data = data[1:]
+ else:
+ data = data[:limit]
+
+ should_have_next_link = True
+ if not reverse_direction and not more:
+ should_have_next_link = False
- if offset > 0:
- # TODO(dbentley): here we need to implement previous in the good way.
- prev = generateLinkForRequest(request, base_params,
- { offset_key : max(0, offset-limit),
- limit_key : limit })
+ # Calculating should_have_previous_link is tricky. It's possible we could
+ # be creating a previous link to a page that would have 0 entities.
+ # That would be suboptimal; what's a better way?
+ should_have_previous_link = False
+ if offset_linkid:
+ should_have_previous_link = True
+ if reverse_direction and not more:
+ should_have_previous_link = False
- if offset > limit:
- # Having a link to the first doesn't make sense on the first page (we're on
- # it). It also doesn't make sense on the second page (because the first
- # page is the previous page).
+ if data:
+ first_displayed_item = data[0]
+ last_displayed_item = data[-1]
+ else:
+ class Dummy(object):
+ pass
+ first_displayed_item = last_displayed_item = Dummy()
+ first_displayed_item.link_id = None
+ newest = next = prev = export_link = ''
+
+ link_creator = LinkCreator(request, idx, limit)
- # NOTE(dbentley): I personally disagree that it's simpler to do that way,
- # because sometimes you want to go to the first page without having to
- # consider what page you're on now.
- newest = generateLinkForGetArgs(request, base_params, {offset_key : 0,
- limit_key : limit})
+ if params.get('list_key_order'):
+ export_link = link_creator.create(export=True)
+
+ if should_have_next_link:
+ next = link_creator.create(offset_linkid=last_displayed_item.link_id)
+
+ if should_have_previous_link:
+ prev = link_creator.create(offset_linkid=first_displayed_item.link_id,
+ reverse_direction=True)
+
+ newest = link_creator.create(offset_linkid='')
+
+ # TODO(dbentley): add a "last" link (which is now possible because we can
+ # query with a reverse linkid sorting
content = {
'idx': idx,
'data': data,
'export': export_link,
- 'first': offset+1,
- 'last': len(data) > 1 and offset+len(data) or None,
+ 'first': first_displayed_item.link_id,
+ 'last': last_displayed_item.link_id,
'logic': logic,
'limit': limit,
'newest': newest,