python--mongodb 翻页工具

gaojinguan

　　由于mongodb的翻页使用的是skip，而不是limit start,end，所以计算的应该是每页应该skip的数据，以下分页工具可以完成mongodb的分页要求

#turn page util
class Paginator(object):
def __init__(self,total_records=None,per_page=None):
#total records
self.total_records = total_records
#perpage size
self.per_page = per_page
#total pages
self.total_pages = 0
#perpage skip infor
self.data={}
self.__judge__()

def __judge__(self):
#caculate total pages
if self.total_records>self.per_page:
self.total_pages = int(floor(self.total_records/float(self.per_page)))
self.data[1]=Page(self,page_number=1,skip=0)
for i in range(1,self.total_pages):
self.data[i+1]=Page(self,page_number=i+1,skip=self.data.skip+self.per_page)
#如果计算出来的页数不恰巧是个整数，那么还需要计算最后一页
if self.total_pages<(self.total_records/float(self.per_page)):
#计算最后一页,因为最后一页肯定是能全页显示的
self.data[self.total_pages+1]=Page(self,self.total_pages+1,skip=self.data[self.total_pages].skip+self.per_page)
else:
self.total_pages=1
self.data[1]=Page(self,1,skip=0)
def get_page(self,page_number):
page_number = int(page_number)
if page_number in self.data.keys():
return self.data[page_number]
else:
return None


#page
class Page(object):
def __init__(self,paginator,page_number=1,skip=0):
self.page_number=page_number
self.skip = skip
self.paginator = paginator
self.next_page_number = self.page_number+1
self.prev_page_number = self.page_number-1
def has_next(self):
return self.page_number<self.paginator.total_records/float(self.paginator.per_page)
def has_prev(self):
return self.page_number>1
def get_next_page(self):
return self.paginator.get_page(self.next_page_number)
def get_prev_page(self):
return self.paginator.get_page(self.prev_page_number)