views.py 文件源码

def prefix_add_tags(request, prefix_id):
    """Adds usages to a prefix from post data"""
    prefix = Prefix.objects.get(pk=prefix_id)
    existing_usages = {u[0] for u in prefix.usages.values_list()}
    usages = set(request.POST.getlist('usages'))

    to_remove = list(existing_usages - usages)
    to_add = list(usages - existing_usages)

    PrefixUsage.objects.filter(prefix=prefix,
                               usage__in=to_remove).delete()
    for usage_key in to_add:
        usage = Usage.objects.get(pk=usage_key)
        try:
            PrefixUsage(prefix=prefix, usage=usage).save()
        except DatabaseError:
            pass

    return HttpResponse()