CODEWITHSUNDEEP
djangodjango-admin
Jon
Jon

Reputation: 3502

Django admin sharing inlines between apps

I have a few apps in my project that I want to be reusable.

First, I have a base content App, which defines how content can be added to a ContentContainer. This allows other models to inherit ContentContainer to get the ability to show content.

Within the content app, I have a Page model that inherits ContentContainer. In another app called events, I have an Event model that also inherites ContentContainer. Basically, my events app depends on my content app (Which is what I want).

This all works great in modeling. I have this in my content app:

class ContentContainer(admin.ModelAdmin):
    #No fields, it just gets referred to by ContentItem

    class Meta:
        ordering = ['modified']

class ContentItem(TimeStampedModel):
    name = models.CharField(max_length=1500)
    page_order = models.IntegerField()
    container = models.ForeignKey(ContentContainer, blank=True)

    #make inheritance know the model type
    objects = InheritanceManager()

    class Meta:
        ordering = [ 'page_order', 'modified', 'name']

    def __unicode__(self):
        return self.name

    def render(self):
        return self.name


class TextContent(ContentItem):
    text = models.CharField(max_length=5000000)

    def render(self):
        return '<p>%s</p>' % self.text

Then in my Events app I do this:

class Event(AnnouncementBase, Addressable, ContentContainer):
    cost = CurrencyField(decimal_places=2, max_digits=10, blank=True, default=0.00)
    start_date = models.DateField(default = datetime.now().date())
    start_time = models.TimeField(default = datetime.now().time())
    end_date = models.DateField(blank=True, default=None, null = True)
    end_time = models.TimeField(blank=True, default=None, null = True)
    rsvp_deadline = models.DateTimeField(blank=True, default=None, null = True)

    class Meta:
        ordering = ['start_date', 'start_time', 'title']

So now events can have content to render.

Here's where things get confusing. I have a slew of inlines defined in admin.py in the content app. They work great there. Also, if I copy an paste them into admin.py in the events app they work there too.

However, I don't want to duplicate code. I want to import the inlines from admin.py into events.py In contents admin.py I have this:

class TextContentInline(admin.TabularInline):
    model = models.TextContent
    extra = 1

class PageAdmin(ContainerAdmin):
    model = models.Page
    inlines = [LinkContentInline, TextContentInline]

There are a bunch of these inlines. How can I share them between my admin.py models? If I try to import them in the events admin.py I get an error that says "The model Page is already registered". I've tried about 5 different things I could think of an none of them work. I am wondering if there is no way to do this. Oh I'm using Django 1.3 too.

Upvotes: 1

Views: 652

Answers (1)

Daniel Roseman
Daniel Roseman

Reputation: 599590

The "already registered" error happens because when a module is imported, Python executes all the statements in the top level - and one of those is the admin.site.register, which is therefore called multiple times.

It's easy to fix this - just catch the exception and ignore it:

try:
    admin.site.register(MyModel, MyModelAdmin)
except admin.sites.AlreadyRegistered:
    pass

An alternative is to keep your inline classes in a completely separate module file - admin_inlines.py, perhaps - and import them from there into every admin that needs them.

Upvotes: 3

Related Questions