Python django.db.models.signals 模块，pre_delete() 实例源码

def get_media_model():
    from django.conf import settings
    from django.apps import apps

    try:
        app_label, model_name = settings.WAGTAILMEDIA_MEDIA_MODEL.split('.')
    except AttributeError:
        return Media
    except ValueError:
        raise ImproperlyConfigured("WAGTAILMEDIA_MEDIA_MODEL must be of the form 'app_label.model_name'")

    media_model = apps.get_model(app_label, model_name)
    if media_model is None:
        raise ImproperlyConfigured(
            "WAGTAILMEDIA_MEDIA_MODEL refers to model '%s' that has not been installed" %
            settings.WAGTAILMEDIA_MEDIA_MODEL
        )
    return media_model


# Receive the pre_delete signal and delete the file associated with the model instance.

def get_document_model():
    from django.conf import settings
    from django.apps import apps

    try:
        app_label, model_name = settings.WAGTAILDOCS_DOCUMENT_MODEL.split('.')
    except AttributeError:
        return Document
    except ValueError:
        raise ImproperlyConfigured("WAGTAILDOCS_DOCUMENT_MODEL must be of the form 'app_label.model_name'")

    document_model = apps.get_model(app_label, model_name)
    if document_model is None:
        raise ImproperlyConfigured(
            "WAGTAILDOCS_DOCUMENT_MODEL refers to model '%s' that has not been installed" %
            settings.WAGTAILDOCS_DOCUMENT_MODEL
        )
    return document_model


# Receive the pre_delete signal and delete the file associated with the model instance.

def remove_record_from_csw(sender, instance, using, **kwargs):
    """
    Delete all csw records associated with the service. We only
    run on service pre_delete to clean up the csw prior to the django db.
    """
    if instance.type in ["WMS", "OWS"]:
        for record in instance.servicelayer_set.all():
            delete_record(record.uuid)
    else:
        delete_record(instance.uuid)

def handle_TiltTempCalibrationPoint_post_save(sender, **kwargs):
    """
    Trigger anything that should happen on update of TiltTempCalibrationPoint
    """

    calibration_point = kwargs.get('instance')
    calibration_point.sensor.set_redis_reload_flag()

# TODO - Add a pre_delete signal to trigger cessation of the relevant tilt_manager process

def delete_file(sender, instance, *args, **kwargs):
    """ Deletes thumbnail files on `pre_delete` """
    if instance.zip_file:
        if os.path.isfile(instance.zip_file.path):
            os.remove(instance.zip_file.path)