Hi All,
Also, check out assignment_tags if you haven't seen them.
https://docs.djangoproject.com/en/dev/howto/custom-template-tags/#assignment-tags
Collin
On Sunday, January 18, 2015 at 8:09:58 AM UTC-5, James Schneider wrote:
>
> If you need it in all of (or a large majority of) your templates, stick
> with the context processor you originally posted, just replace the
> Category.objects.get() call with the custom manager call. Your templates
> would then have access to {{ MAIN_CATEGORY }}. And with a context
> processor, that literally means every template, including login forms,
> password resets, etc. which may or may not be acceptable.
>
> If you don't necessarily need it in all templates, but you are using
> class-based views, you can write a custom mixin that overrides
> get_context_data() to add in the MAIN_CATEGORY variable for your templates,
> but only if you are not using the aforementioned context processor to
> populate it (otherwise you are doubling the work to set the same variable).
>
> Templates are the only tricky part here. Everywhere else you can call your
> custom manager method directly.
>
> -James
> On Jan 18, 2015 4:47 AM, "ThomasTheDjangoFan" <
> stefan.eich...@googlemail.com <javascript:>> wrote:
>
>> Hi James,
>>
>> thanks a lot for pointing me to the models.Mangager option. Now this is
>> really interesting. I will definetly check out how caching works.
>>
>> Now the question is:
>> How do I now access the CategoryManager.get_main_category() in my
>> template.html? I guess I have to pass it over to context within the view?
>>
>>
>> Am Sonntag, 18. Januar 2015 12:28:30 UTC+1 schrieb James Schneider:
>>>
>>> If I understand you right, you want to set MAIN_CATEGORY as a "global"
>>> variable/setting containing a Category object with an ID of 1. Is that
>>> right? If so...
>>>
>>> Rather than populating a "global" variable, I would instead create a
>>> custom model manager for the Category model:
>>>
>>> https://docs.djangoproject.com/en/1.7/topics/db/managers/
>>> #custom-managers
>>>
>>> It would be a pretty simple override just to add an extra method:
>>>
>>> class CategoryManager(models.Manager):
>>> def get_main_category(self):
>>> return Category.objects.get(pk=1)
>>>
>>> class Category(models.Model):
>>> <...other fields...>
>>> objects = CategoryManager()
>>>
>>>
>>> Then, anywhere you needed the value that would be accessed via
>>> MAIN_CATEGORY, you would instead use 'main_category =
>>> Category.objects.get_main_category()'.
>>>
>>> If you ever need to change the category that is returned, the only place
>>> you'll need to update the code/PK is in the manager method definition. Much
>>> more flexible than a simple variable in settings.py.
>>>
>>> Realize that the example above is quite a naive/simplistic
>>> implementation, and can benefit from other optimizations (such as a basic
>>> caching mechanism in the CategoryManager in the event it is called multiple
>>> times during a request to avoid multiple queries for the same data, among
>>> others). Check out https://github.com/django/django/blob/master/django/
>>> contrib/auth/backends.py#L41 for how Django handles caching for
>>> permission checks (which are often called multiple times per request).
>>>
>>> To avoid the dependency on a specific key/PK, you may want to consider
>>> adding a boolean field to Category called 'is_main' that defaults to False.
>>> Then set the field to True for the single category you want to be the main
>>> one. Then your manager query would look like
>>> Category.objects.get(is_main=True).
>>> Just make sure you only have one category with is_main set to True (if you
>>> change your mind on which category will be the main category, set all of
>>> the Categories to False, and then reset the new main category to True). If
>>> you are confident that it will never change, though, you'll probably be
>>> fine.
>>>
>>> -James
>>>
>>>
>>> On Jan 18, 2015 2:26 AM, "ThomasTheDjangoFan" <stefan.eich...@
>>> googlemail.com> wrote:
>>>
>>>> Ladies and gentleman,
>>>>
>>>> I am new to Django and would really love to have a solution for this:
>>>>
>>>> My goal is to share generated settings between my views/models and
>>>> templates, without repeating myself.
>>>>
>>>> Right now I have following code, where the problem appears:
>>>>
>>>> #MY_CONTEXT_PROCESSOR.PY
>>>> from django.conf import settings
>>>>
>>>> def setDataToContext (request):
>>>> """
>>>> Send settings to context of tempalte
>>>> """
>>>>
>>>> #GENERATED STUFF
>>>> #Prepare common Objects
>>>> main_category = Category.objects.get(id=1)
>>>>
>>>> return {
>>>> 'settings': settings, # Global Django Settings
>>>> 'MAIN_CATEGORY': main_category, # Make category available in
>>>> template - Question: How do I make this available in views/models as
>>>> settings.MAIN_CATEGORY?
>>>> }
>>>>
>>>>
>>>> The main question is:
>>>>
>>>> *How can I make the generic constant MAIN_CATEGORY available in
>>>> views/models as settings.MAIN_CATEGORY without repeating myself?*
>>>> I am really looking forward to see your solutions.
>>>>
>>>> Kind regards
>>>> Thomas
>>>>
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