Hello, I am trying to implement a cache system using the post_save signal. The problem is the code below, a Thread subclass that ends up calling run(), the cache database never runs. It's driving me crazy!!! Is there something going on with the way Django cache's queries which is what I expect? Can I turn this off? This is the Thread subclass code is below.
What I am trying to do is implement a staticpages app which is much like flatpages but it adds a menu foreign key to what is basically a flatpage. I am trying to make a cache system whereby when a user saves a link or a menu, the below code rebuilds the XHTML to use in the staticpage Context. Here is a sample run: 1) I am in the admin and change a menu to consist of a title called "Cool Sites 222" and three links 2) post_save runs and here is what is supposed to be saved in the database (a print is called in my code: Menu 2 <div id=""> <h3>Cool Sites 222</h3> <ul> <li><a title="Google Inc" href="http://www.google.com/";>Google Inc</ a></li> <li><a title="Microsoft" href="http://www.microsoft.com";>Microsoft</ a></li> <li><a title="Ryan Kaskel" href="http://www.ryankaskel.com";>Ryan Kaskel</a></li> <li><a title="Yahoo! Inc" href="http://www.yahoo.com";>Yahoo Homepage</ a></li> </ul> </div> If I don't change anything in the menu, eventually it gets the right XHTML and prints it 3) The cached XHTML in the database is never changed and still contains the information from its creation. I think this is a bug because the following this code: def _cache_menu(self, menu, xhtml): """ Stores xhtml into the CachedMenuXhtml table where the row's menu matches the menu_obj. """ if menu and xhtml: cm = self.CachedMenuXhtml.objects.filter(menu__exact=menu) if cm[0]: print cm[0].xhtml cm[0].xhtml = xhtml cm[0].save() print cm[0].xhtml print xhtml else: new_cm = self.CachedMenuXhtml(menu=menu,xhtml=xhtml) new_cm.save() produces... <div id=""> <h3>Cool Sites</h3> <ul> <li><a title="Microsoft" href="http://www.microsoft.com";>Microsoft</ a></li> <li><a title="Ryan Kaskel" href="http://www.ryankaskel.com";>Ryan Kaskel</a></li> <li><a title="Yahoo! Inc" href="http://www.yahoo.com";>Yahoo Homepage</ a></li> </ul> </div> [11/Jul/2009 05:03:47] "POST /admin/staticpages/menu/2/ HTTP/1.1" 302 0 <div id=""> <h3>Cool Sites</h3> <ul> <li><a title="Microsoft" href="http://www.microsoft.com";>Microsoft</ a></li> <li><a title="Ryan Kaskel" href="http://www.ryankaskel.com";>Ryan Kaskel</a></li> <li><a title="Yahoo! Inc" href="http://www.yahoo.com";>Yahoo Homepage</ a></li> </ul> </div> <div id=""> <h3>Cool Sites 222</h3> <ul> <li><a title="Google Inc" href="http://www.google.com/";>Google Inc</ a></li> <li><a title="Microsoft" href="http://www.microsoft.com";>Microsoft</ a></li> <li><a title="Ryan Kaskel" href="http://www.ryankaskel.com";>Ryan Kaskel</a></li> <li><a title="Yahoo! Inc" href="http://www.yahoo.com";>Yahoo Homepage</ a></li> </ul> </div> -------------------- CODE for Thread subclass that post_save signal calls # Signlas for caching of menu XHTML import threading from django.template.loader import get_template from django.template import Context from django.utils.safestring import mark_safe from django.core.exceptions import ObjectDoesNotExist from asqcom.apps.staticpages.settings import STATICPAGE_TEMPLATE, MENU_TEMPLATE from asqcom.apps.staticpages.settings import LINK_TEMPLATE, MENU_CSS_ID class GenerateMenuXhtml(threading.Thread): """ Subclasses a threading.Thread class to generate a menu's XHTML in a separate thread. All Link objects that have this menu associated with it are gathered and combined in an XHTML unordered list. If the sender is of type Link, then all menus associated with that link are iterated through and rebuilt. """ def __init__(self, instance): from asqcom.apps.staticpages.models import Menu, Link, CachedMenuXhtml self.Link = Link self.Menu = Menu self.CachedMenuXhtml = CachedMenuXhtml self.instance = instance self.menus_to_build = [] self.xhtml_for_menus = [] self.menus_for_cache = [] threading.Thread.__init__(self) def _cache_menu(self, menu, xhtml): """ Stores xhtml into the CachedMenuXhtml table where the row's menu matches the menu_obj. """ if menu and xhtml: print menu print xhtml cm = self.CachedMenuXhtml.objects.filter(menu__exact=menu) if cm[0]: cm[0].xhtml = xhtml cm[0].save() else: new_cm = self.CachedMenuXhtml(menu=menu,xhtml=xhtml) new_cm.save() def cache_menus(self): """ Unpacks the menu objects and the XHTML for that menu and iterates through the list calling _cache_menu which does the real work. """ for pair in self.menus_for_cache: self._cache_menu(pair[0],pair[1]) def _generate_xhtml(self, menu): link_tmpl = get_template(LINK_TEMPLATE or 'staticpages/ link_default.html') menu_tmpl = get_template(MENU_TEMPLATE or 'staticpages/ menu_default.html') # Retrieve all links associated with this menu links = menu.links.all().order_by('text') links_strings = [] for link in links: link_ctx = Context({'title': mark_safe(link.title), 'url': mark_safe(link.url), 'text': mark_safe(link.text)}) links_strings.append(link_tmpl.render(link_ctx)) # Create the menu context, all that is missing from here is are the links menu_ctx = Context({'title': mark_safe(menu.title), 'menu_css_id': mark_safe(MENU_CSS_ID), 'links': mark_safe(''.join (links_strings))}) return menu_tmpl.render(menu_ctx) def run(self): if isinstance(self.instance, self.Link): menus = self.Menu.objects.filter (links__exact=self.instance) for menu in menus: self.menus_to_build.append(menu) else: self.menus_to_build.append(self.instance) for menu in self.menus_to_build: self.xhtml_for_menus.append(self._generate_xhtml(menu)) self.menus_for_cache = zip(self.menus_to_build, self.xhtml_for_menus) self.cache_menus() --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. 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