Well, the 10 rows for 30 p was just an example for understanding :) The idea of the was in order to do only 1 query but definitely you are right, it wasn't worth of! On 18 Aug 2014 12:23, "Niphlod" <[email protected]> wrote:
> if you're presenting 10 rows at a time and expecting the user to navigate > 30 pages, "you're doing it wrong", from the UX side of things. > On the other side, there's no reason to cache "in advance" something the > user will never ask. Let the cache be the cache. If you need to "warm it > up", just do > > cached_it = False #you logic to see if the cache needs to be updated > if not cached_it: > for i in range(number_of_pages): > rtn = db(query).select(limitby=(number_of_pages*no_of_records, > (number_of_pages+1)*no_of_records)) > cached_it = True > > but mind that is quite silly. > > On Saturday, August 16, 2014 10:26:45 AM UTC+2, Giacomo Dorigo wrote: >> >> I have read the manual recipe on pagination: >> http://web2py.com/books/default/chapter/29/14/other-recipes#Pagination >> >> That works fine if we just want to have a page aware if it has a previous >> or next one, but what if we want also to get the list of all next pages? >> i.e. by putting a link for each next page, near the next "button"? >> >> Let's say I have 300 records in a table, I want to serve 10 per time. If >> I am serving page 1, there are other 29 pages more, so I want to be able to >> put links at least to page 2, 3, 4, 5, 6.... so to make navigation easier. >> >> The recipe in the manual is quite good, because it allows to get only the >> 10 elements I need to serve in the current page, but my page do not know >> how many pages there are in total. >> >> I was thinking to solve this creating a PageThread class taking care of >> storing the information about the whole. My idea was to let this class >> making the query for all items in the table and then creating the single >> pages to serve. >> But the problem here is that when the controller will instantiate this >> class it will reset it all times, so it will make the query to the whole >> table every time, so it's wasted. >> Probably this can be solved using the web2py built-in count() or is there >> a possibility to use cache? >> Does anybody already solved this problem somewhere? >> >> This is a sample of the code of the two classes I thought about: >> >> class PageThread(object): >> def __init__(self, items, items_per_page=10): >> self.items = items >> self.items_count = len(self.items) >> self.items_per_page = items_per_page >> self.__set_number_of_pages() >> self.__load_pages() >> >> def __set_number_of_pages(self): >> self.number_of_pages = self.items_count/self.items_per_page + 1 >> if self.items_count % self.items_per_page else self.items_count/self. >> items_per_page >> >> def __load_pages(self): >> self.pages = [Page(p_id, self.items[(p_id-1)*self.items_per_page: >> p_id*self.items_per_page]) for p_id in range(1, self.number_of_pages+1)] >> >> >> class Page(object): >> def __init__(self, id, items): >> # id is the unique number of the page in the PageThread >> self.id = id >> self.items = items >> >> def __str__(self): >> return 'Page n.{}, {} items: {}'.format(self.id, len(self.items), >> self.items) >> >> While this was the original Page that just knows if it has previous or >> next: >> >> class Page(object): >> def __init__(self, page, items_per_page=10): >> self.id = int(page) >> self.items_per_page = items_per_page >> # range gives you an item more in order to check if there is a >> next page >> self.range = ((self.id-1)*self.items_per_page, self.id*self. >> items_per_page+1) >> >> >> def load_items(self, rows): >> # where rows are those returned from a select query to the db >> if len(rows) > self.items_per_page : >> self.has_next = True >> self.items = rows[:-1] >> else: >> self.has_next = False >> self.items = rows >> >> >> def get_page_navigation_div(self, **request_vars): >> contents = [] >> request_vars.update({'items_per_page': self.n_items}) >> if self.has_previous: >> request_vars.update({'page': self.id-1}) >> contents.append( A('<<< previous', _class='nav-previous', >> _href=URL(vars=request_vars)) ) >> for n in range(1, self.id): >> request_vars.update({'page': n}) >> contents.append( A(' %s' % n, _class='nav-page', _href=URL( >> vars=request_vars)) ) >> if self.has_next: >> request_vars.update({'page': self.id+1}) >> contents.append( A('next >>>', _class='nav-next', _href=URL( >> vars=request_vars)) ) >> return DIV(*contents, _id='page_navigation') >> >> In the controller you use like this: >> >> page = Page(request.vars.page, 10) >> page.load_items(db(your_query).select(limitby=page.range)) >> #do stuff >> return dict(page=page) >> >> >> -- > Resources: > - http://web2py.com > - http://web2py.com/book (Documentation) > - http://github.com/web2py/web2py (Source code) > - https://code.google.com/p/web2py/issues/list (Report Issues) > --- > You received this message because you are subscribed to a topic in the > Google Groups "web2py-users" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/web2py/-awUNbuI_t8/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- Resources: - http://web2py.com - http://web2py.com/book (Documentation) - http://github.com/web2py/web2py (Source code) - https://code.google.com/p/web2py/issues/list (Report Issues) --- You received this message because you are subscribed to the Google Groups "web2py-users" group. 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