netbox/netbox/extras/utils.py

from django.db.models import Q
from django.utils.deconstruct import deconstructible
from taggit.managers import _TaggableManager

from netbox.registry import registry


def is_taggable(obj):
    """
    Return True if the instance can have Tags assigned to it; False otherwise.
    """
    if hasattr(obj, 'tags'):
        if issubclass(obj.tags.__class__, _TaggableManager):
            return True
    return False


def image_upload(instance, filename):
    """
    Return a path for uploading image attachments.
    """
    path = 'image-attachments/'

    # Rename the file to the provided name, if any. Attempt to preserve the file extension.
    extension = filename.rsplit('.')[-1].lower()
    if instance.name and extension in ['bmp', 'gif', 'jpeg', 'jpg', 'png']:
        filename = '.'.join([instance.name, extension])
    elif instance.name:
        filename = instance.name

    return '{}{}_{}_{}'.format(path, instance.content_type.name, instance.object_id, filename)


@deconstructible
class FeatureQuery:
    """
    Helper class that delays evaluation of the registry contents for the functionality store
    until it has been populated.
    """
    def __init__(self, feature):
        self.feature = feature

    def __call__(self):
        return self.get_query()

    def get_query(self):
        """
        Given an extras feature, return a Q object for content type lookup
        """
        query = Q()
        for app_label, models in registry['model_features'][self.feature].items():
            query |= Q(app_label=app_label, model__in=models)

        return query


def register_features(model, features):
    """
    Register model features in the application registry.
    """
    app_label, model_name = model._meta.label_lower.split('.')
    for feature in features:
        try:
            registry['model_features'][feature][app_label].add(model_name)
        except KeyError:
            raise KeyError(
                f"{feature} is not a valid model feature! Valid keys are: {registry['model_features'].keys()}"
            )


def is_script(obj):
    """
    Returns True if the object is a Script.
    """
    from .scripts import Script
    try:
        return issubclass(obj, Script) and obj != Script
    except TypeError:
        return False


def is_report(obj):
    """
    Returns True if the given object is a Report.
    """
    from .reports import Report
    try:
        return issubclass(obj, Report) and obj != Report
    except TypeError:
        return False