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# GNU MediaGoblin -- federated, autonomous media hosting
# Copyright (C) 2011, 2012 MediaGoblin contributors. See AUTHORS.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import copy
from math import ceil, floor
from itertools import count
from werkzeug.datastructures import MultiDict
from six.moves import urllib
PAGINATION_DEFAULT_PER_PAGE = 30
class Pagination:
"""
Pagination class for database queries.
Initialization through __init__(self, cursor, page=1, per_page=2),
get actual data slice through __call__().
"""
def __init__(self, page, cursor, per_page=PAGINATION_DEFAULT_PER_PAGE,
jump_to_id=False):
"""
Initializes Pagination
Args:
- page: requested page
- per_page: number of objects per page
- cursor: db cursor
- jump_to_id: object id, sets the page to the page containing the
object with id == jump_to_id.
"""
self.page = page
self.per_page = per_page
self.cursor = cursor
self.total_count = self.cursor.count()
self.active_id = None
if jump_to_id:
cursor = copy.copy(self.cursor)
for (doc, increment) in list(zip(cursor, count(0))):
if doc.id == jump_to_id:
self.page = 1 + int(floor(increment / self.per_page))
self.active_id = jump_to_id
break
def __call__(self):
"""
Returns slice of objects for the requested page
"""
# TODO, return None for out of index so templates can
# distinguish between empty galleries and out-of-bound pages???
return self.cursor.slice(
(self.page - 1) * self.per_page,
self.page * self.per_page)
@property
def pages(self):
return int(ceil(self.total_count / float(self.per_page)))
@property
def has_prev(self):
return self.page > 1
@property
def has_next(self):
return self.page < self.pages
def iter_pages(self, left_edge=2, left_current=2,
right_current=5, right_edge=2):
last = 0
for num in range(1, self.pages + 1):
if num <= left_edge or \
(num > self.page - left_current - 1 and \
num < self.page + right_current) or \
num > self.pages - right_edge:
if last + 1 != num:
yield None
yield num
last = num
def get_page_url_explicit(self, base_url, get_params, page_no):
"""
Get a page url by adding a page= parameter to the base url
"""
if isinstance(get_params, MultiDict):
new_get_params = get_params.to_dict()
else:
new_get_params = dict(get_params) or {}
new_get_params['page'] = page_no
return "{}?{}".format(
base_url, urllib.parse.urlencode(new_get_params))
def get_page_url(self, request, page_no):
"""
Get a new page url based of the request, and the new page number.
This is a nice wrapper around get_page_url_explicit()
"""
return self.get_page_url_explicit(
request.full_path, request.GET, page_no)
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