slim/utils/pagination.py
import math
def pagination_calc(items_count, page_size, cur_page=1, nearby=2):
"""
:param nearby:
:param items_count: count of all items
:param page_size: size of one page
:param cur_page: current page number, accept string digit
:return: num of pages, an iterator
"""
if type(cur_page) == str:
# noinspection PyUnresolvedReferences
cur_page = int(cur_page) if cur_page.isdigit() else 1
elif type(cur_page) == int:
if cur_page <= 0:
cur_page = 1
else:
cur_page = 1
page_count = 1 if page_size == -1 else int(math.ceil(items_count / page_size))
items_length = nearby * 2 + 1
# if first page in page items, first_page is None,
# it means the "go to first page" button should not be available.
first_page = None
last_page = None
prev_page = cur_page - 1 if cur_page != 1 else None
next_page = cur_page + 1 if cur_page != page_count else None
if page_count <= items_length:
number_items = range(1, page_count + 1)
elif cur_page <= nearby:
# start of items
number_items = range(1, items_length + 1)
last_page = True
elif cur_page >= page_count - nearby:
# end of items
number_items = range(page_count - items_length + 1, page_count + 1)
first_page = True
else:
number_items = range(cur_page - nearby, cur_page + nearby + 1)
first_page, last_page = True, True
if first_page:
first_page = 1
if last_page:
last_page = page_count
return {
'cur_page': cur_page,
'prev_page': prev_page,
'next_page': next_page,
'first_page': first_page,
'last_page': last_page,
'numbers': list(number_items),
'info': {
'page_size': page_size, # 分页大小
'page_count': page_count, # 页数
'items_count': items_count, # 总项个数
}
}