python--mongodb 翻页工具

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[i].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)