MemcachedKeyCharacterError

[DragosChirila]

Hi,

I am trying to use the @memoize decorator to cache a method in a view, with python-memcached present, like below:

class BlogView(generic.ListView, CoreBreadcrumbs):
    template_name = 'blog/blog.html'
    context_object_name = 'items'

    @memoize(timeout=3600)
    def get_paginate_by(self, queryset):
        return BlogSettings.objects.get().howmany_perpage
...

and I get the following error:

MemcachedKeyCharacterError: Control/space characters not allowed (key=':1:blog.views.BlogView.get_paginate_by.<blog.views.BlogView object at 0x03518AD0>_memver')

Full traceback - https://gist.github.com/DragosChirila/ce814ffd2a4d24e82c78c8cd013288e6

Am I doing something wrong here? Could you please advice?

[tvavrys]

Hi there,

please try to overwrite __repr__ with something simpler or use Redis. It seems like Memcached has character limitations for keys.

[DragosChirila]

Thanks! Indeed, using something like

    def __repr__(self):
        """ Overwrite this for memcache key generation.
        """
        return '{}.{}'.format(self.__module__, self.__class__.__name__)

seems to work.

On the other hand, I tried to use the make_name parameter but without success. Do you have a working example with a custom make_name method?

[tvavrys]

What do you mean by "use the make_name parameter"? What is it?

EDIT: Nevermind. I get it now :) I'll look into it later. Thanks.

[tvavrys]

Looking at the code - make_name has to be callable. What did you use? String?

[DragosChirila]

I did it like this:

    @memoize(timeout=3600, make_name=make_name_for_view)
    def get_paginate_by(self, queryset):
        return BlogSettings.objects.get().howmany_perpage

where

def make_name_for_view(name):
    return 'my custom name'

But, make_name_for_view never gets called.