""" This is the *abstract* django models for many of the database objects in Evennia. A django abstract (obs, not the same as a Python metaclass!) is a model which is not actually created in the database, but which only exists for other models to inherit from, to avoid code duplication. Any model can import and inherit from these classes. Attributes are database objects stored on other objects. The implementing class needs to supply a ForeignKey field attr_object pointing to the kind of object being mapped. Attributes storing iterables actually store special types of iterables named PackedList/PackedDict respectively. These make sure to save changes to them to database - this is criticial in order to allow for obj.db.mylist[2] = data. Also, all dbobjects are saved as dbrefs but are also aggressively cached. TypedObjects are objects 'decorated' with a typeclass - that is, the typeclass (which is a normal Python class implementing some special tricks with its get/set attribute methods, allows for the creation of all sorts of different objects all with the same database object underneath. Usually attributes are used to permanently store things not hard-coded as field on the database object. The admin should usually not have to deal directly with the database object layer. This module also contains the Managers for the respective models; inherit from these to create custom managers. """ from django.db.models import signals from django.db import models from django.core.exceptions import ObjectDoesNotExist from django.conf import settings from django.utils.encoding import smart_str from src.typeclasses.attributes import Attribute, AttributeHandler, NAttributeHandler from src.typeclasses.tags import Tag, TagHandler, AliasHandler, PermissionHandler from src.utils.idmapper.models import SharedMemoryModel from src.utils.idmapper.base import SharedMemoryModelBase from src.server.caches import get_prop_cache, set_prop_cache #from src.server.caches import set_attr_cache #from src.server.caches import call_ndb_hooks #from src.server.models import ServerConfig from src.typeclasses import managers from src.locks.lockhandler import LockHandler from src.utils.utils import ( is_iter, inherits_from, lazy_property, class_from_module) from src.typeclasses.django_new_patch import patched_new __all__ = ("Attribute", "TypeNick", "TypedObject") TICKER_HANDLER = None _PERMISSION_HIERARCHY = [p.lower() for p in settings.PERMISSION_HIERARCHY] _TYPECLASS_AGGRESSIVE_CACHE = settings.TYPECLASS_AGGRESSIVE_CACHE _GA = object.__getattribute__ _SA = object.__setattr__ #------------------------------------------------------------ # # Typed Objects # #------------------------------------------------------------ # # Meta class for typeclasses # # signal receivers. Assigned in __new__ def post_save(sender, instance, created, **kwargs): """ Receives a signal just after the object is saved. """ if created: instance.at_first_save() #TODO - put OOB handler here? class TypeclassBase(SharedMemoryModelBase): """ Metaclass which should be set for the root of model proxies that don't define any new fields, like Object, Script etc. """ def __new__(cls, name, bases, attrs): """ We must define our Typeclasses as proxies. We also store the path directly on the class, this is required by managers. """ # storage of stats attrs["typename"] = name#cls.__name__ attrs["path"] = "%s.%s" % (attrs["__module__"], name) # typeclass proxy setup if not "Meta" in attrs: class Meta: proxy = True attrs["Meta"] = Meta attrs["Meta"].proxy = True # patch for django proxy multi-inheritance # this is a copy of django.db.models.base.__new__ # with a few lines changed as per # https://code.djangoproject.com/ticket/11560 new_class = patched_new(cls, name, bases, attrs) # attach signal signals.post_save.connect(post_save, sender=new_class) return new_class # # Main TypedObject abstraction # class TypedObject(SharedMemoryModel): """ Abstract Django model. This is the basis for a typed object. It also contains all the mechanics for managing connected attributes. The TypedObject has the following properties: key - main name name - alias for key typeclass_path - the path to the decorating typeclass typeclass - auto-linked typeclass date_created - time stamp of object creation permissions - perm strings dbref - #id of object db - persistent attribute storage ndb - non-persistent attribute storage """ # # TypedObject Database Model setup # # # These databse fields are all accessed and set using their corresponding # properties, named same as the field, but without the db_* prefix # (no separate save() call is needed) # Main identifier of the object, for searching. Is accessed with self.key # or self.name db_key = models.CharField('key', max_length=255, db_index=True) # This is the python path to the type class this object is tied to. The # typeclass is what defines what kind of Object this is) db_typeclass_path = models.CharField('typeclass', max_length=255, null=True, help_text="this defines what 'type' of entity this is. This variable holds a Python path to a module with a valid Evennia Typeclass.") # Creation date. This is not changed once the object is created. db_date_created = models.DateTimeField('creation date', editable=False, auto_now_add=True) # Lock storage db_lock_storage = models.TextField('locks', blank=True, help_text="locks limit access to an entity. A lock is defined as a 'lock string' on the form 'type:lockfunctions', defining what functionality is locked and how to determine access. Not defining a lock means no access is granted.") # many2many relationships db_attributes = models.ManyToManyField(Attribute, null=True, help_text='attributes on this object. An attribute can hold any pickle-able python object (see docs for special cases).') db_tags = models.ManyToManyField(Tag, null=True, help_text='tags on this object. Tags are simple string markers to identify, group and alias objects.') # Database manager objects = managers.TypedObjectManager() # quick on-object typeclass cache for speed _cached_typeclass = None # typeclass mechanism def __init__(self, *args, **kwargs): """ This is the main function of the typeclass system - to dynamically re-apply a class based on the db_typeclass_path rather than use the one in the model. """ typeclass_path = kwargs.pop("typeclass", None) super(TypedObject, self).__init__(*args, **kwargs) if typeclass_path: self.__class__ = class_from_module(typeclass_path) self.db_typclass_path = typeclass_path elif self.db_typeclass_path: self.__class__ = class_from_module(self.db_typeclass_path) else: self.db_typeclass_path = "%s.%s" % (self.__module__, self.__class__.__name__) # important to put this at the end since _meta is based on the set __class__ self.__dbclass__ = self._meta.proxy_for_model or self.__class__ # initialize all handlers in a lazy fashion @lazy_property def attributes(self): return AttributeHandler(self) @lazy_property def locks(self): return LockHandler(self) @lazy_property def tags(self): return TagHandler(self) @lazy_property def aliases(self): return AliasHandler(self) @lazy_property def permissions(self): return PermissionHandler(self) @lazy_property def nattributes(self): return NAttributeHandler(self) class Meta: """ Django setup info. """ abstract = True verbose_name = "Evennia Database Object" ordering = ['-db_date_created', 'id', 'db_typeclass_path', 'db_key'] # wrapper # Wrapper properties to easily set database fields. These are # @property decorators that allows to access these fields using # normal python operations (without having to remember to save() # etc). So e.g. a property 'attr' has a get/set/del decorator # defined that allows the user to do self.attr = value, # value = self.attr and del self.attr respectively (where self # is the object in question). # name property (alias to self.key) def __name_get(self): return self.key def __name_set(self, value): self.key = value def __name_del(self): raise Exception("Cannot delete name") name = property(__name_get, __name_set, __name_del) # # # TypedObject main class methods and properties # # def __eq__(self, other): return other and hasattr(other, 'dbid') and self.dbid == other.dbid def __str__(self): return smart_str("%s" % self.db_key) def __unicode__(self): return u"%s" % self.db_key #@property def __dbid_get(self): """ Caches and returns the unique id of the object. Use this instead of self.id, which is not cached. """ dbid = get_prop_cache(self, "_dbid") if not dbid: dbid = self.id set_prop_cache(self, "_dbid", dbid) return dbid def __dbid_set(self, value): raise Exception("dbid cannot be set!") def __dbid_del(self): raise Exception("dbid cannot be deleted!") dbid = property(__dbid_get, __dbid_set, __dbid_del) #@property def __dbref_get(self): """ Returns the object's dbref on the form #NN. """ return "#%s" % self.dbid def __dbref_set(self): raise Exception("dbref cannot be set!") def __dbref_del(self): raise Exception("dbref cannot be deleted!") dbref = property(__dbref_get, __dbref_set, __dbref_del) # # Object manipulation methods # def is_typeclass(self, typeclass, exact=True): """ Returns true if this object has this type OR has a typeclass which is an subclass of the given typeclass. This operates on the actually loaded typeclass (this is important since a failing typeclass may instead have its default currently loaded) typeclass - can be a class object or the python path to such an object to match against. typeclass - a class or the full python path to the class exact - returns true only if the object's type is exactly this typeclass, ignoring parents. """ if not isinstance(typeclass, basestring): typeclass = typeclass.path if exact: return typeclass == self.path else: # check parent chain selfpath = self.path return any(cls for cls in self.__class__.mro() if cls.path == selfpath) def swap_typeclass(self, new_typeclass, clean_attributes=False, run_start_hooks=True, no_default=True): """ This performs an in-situ swap of the typeclass. This means that in-game, this object will suddenly be something else. Player will not be affected. To 'move' a player to a different object entirely (while retaining this object's type), use self.player.swap_object(). Note that this might be an error prone operation if the old/new typeclass was heavily customized - your code might expect one and not the other, so be careful to bug test your code if using this feature! Often its easiest to create a new object and just swap the player over to that one instead. Arguments: new_typeclass (path/classobj) - type to switch to clean_attributes (bool/list) - will delete all attributes stored on this object (but not any of the database fields such as name or location). You can't get attributes back, but this is often the safest bet to make sure nothing in the new typeclass clashes with the old one. If you supply a list, only those named attributes will be cleared. run_start_hooks - trigger the start hooks of the object, as if it was created for the first time. no_default - if this is active, the swapper will not allow for swapping to a default typeclass in case the given one fails for some reason. Instead the old one will be preserved. Returns: boolean True/False depending on if the swap worked or not. """ if not callable(new_typeclass): # this is an actual class object - build the path new_typeclass = class_from_module(new_typeclass) # if we get to this point, the class is ok. if inherits_from(self, "src.scripts.models.ScriptDB"): if self.interval > 0: raise RuntimeError("Cannot use swap_typeclass on time-dependent " \ "Script '%s'.\nStop and start a new Script of the " \ "right type instead." % self.key) self.typeclass_path = new_typeclass.path self.__class__ = new_typeclass if clean_attributes: # Clean out old attributes if is_iter(clean_attributes): for attr in clean_attributes: self.attributes.remove(attr) for nattr in clean_attributes: if hasattr(self.ndb, nattr): self.nattributes.remove(nattr) else: #print "deleting attrs ..." self.attributes.clear() self.nattributes.clear() if run_start_hooks: # fake this call to mimic the first save self.at_first_save() # # Lock / permission methods # def access(self, accessing_obj, access_type='read', default=False, **kwargs): """ Determines if another object has permission to access. accessing_obj - object trying to access this one access_type - type of access sought default - what to return if no lock of access_type was found **kwargs - this is ignored, but is there to make the api consistent with the object-typeclass method access, which use it to feed to its hook methods. """ return self.locks.check(accessing_obj, access_type=access_type, default=default) def check_permstring(self, permstring): """ This explicitly checks if we hold particular permission without involving any locks. It does -not- trigger the at_access hook. """ if hasattr(self, "player"): if self.player and self.player.is_superuser: return True else: if self.is_superuser: return True if not permstring: return False perm = permstring.lower() perms = [p.lower() for p in self.permissions.all()] if perm in perms: # simplest case - we have a direct match return True if perm in _PERMISSION_HIERARCHY: # check if we have a higher hierarchy position ppos = _PERMISSION_HIERARCHY.index(perm) return any(True for hpos, hperm in enumerate(_PERMISSION_HIERARCHY) if hperm in perms and hpos > ppos) return False # # Deletion methods # def _deleted(self, *args, **kwargs): "Scrambling method for already deleted objects" raise ObjectDoesNotExist("This object was already deleted!") _is_deleted = False # this is checked by db_* wrappers def delete(self): "Cleaning up handlers on the typeclass level" global TICKER_HANDLER if not TICKER_HANDLER: from src.scripts.tickerhandler import TICKER_HANDLER TICKER_HANDLER.remove(self) # removes objects' all ticker subscriptions self.permissions.clear() self.attributes.clear() self.aliases.clear() if hasattr(self, "nicks"): self.nicks.clear() self.flush_from_cache() # scrambling properties self.delete = self._deleted self._is_deleted = True super(TypedObject, self).delete() # # Memory management # def flush_from_cache(self): """ Flush this object instance from cache, forcing an object reload. Note that this will kill all temporary attributes on this object since it will be recreated as a new Typeclass instance. """ self.__class__.flush_cached_instance(self) # # Attribute storage # #@property db def __db_get(self): """ Attribute handler wrapper. Allows for the syntax obj.db.attrname = value and value = obj.db.attrname and del obj.db.attrname and all_attr = obj.db.all() (unless there is an attribute named 'all', in which case that will be returned instead). """ try: return self._db_holder except AttributeError: class DbHolder(object): "Holder for allowing property access of attributes" def __init__(self, obj): _SA(self, "attrhandler", obj.attributes) def __getattribute__(self, attrname): if attrname == 'all': # we allow to overload our default .all attr = _GA(self, "attrhandler").get("all") if attr: return attr return self.all return _GA(self, "attrhandler").get(attrname) def __setattr__(self, attrname, value): _GA(self, "attrhandler").add(attrname, value) def __delattr__(self, attrname): _GA(self, "attrhandler").remove(attrname) def get_all(self): return _GA(self, "attrhandler").all() all = property(get_all) self._db_holder = DbHolder(self) return self._db_holder #@db.setter def __db_set(self, value): "Stop accidentally replacing the db object" string = "Cannot assign directly to db object! " string += "Use db.attr=value instead." raise Exception(string) #@db.deleter def __db_del(self): "Stop accidental deletion." raise Exception("Cannot delete the db object!") db = property(__db_get, __db_set, __db_del) # # Non-persistent (ndb) storage # #@property ndb def __ndb_get(self): """ A non-attr_obj store (ndb: NonDataBase). Everything stored to this is guaranteed to be cleared when a server is shutdown. Syntax is same as for the _get_db_holder() method and property, e.g. obj.ndb.attr = value etc. """ try: return self._ndb_holder except AttributeError: class NDbHolder(object): "Holder for allowing property access of attributes" def __init__(self, obj): _SA(self, "nattrhandler", obj.nattributes) def __getattribute__(self, attrname): if attrname == 'all': # we allow to overload our default .all attr = _GA(self, "nattrhandler").get('all') if attr: return attr return self.all return _GA(self, "nattrhandler").get(attrname) def __setattr__(self, attrname, value): _GA(self, "nattrhandler").add(attrname, value) def __delattr__(self, attrname): _GA(self, "nattrhandler").remove(attrname) def get_all(self): return _GA(self, "nattrhandler").all() all = property(get_all) self._ndb_holder = NDbHolder(self) return self._ndb_holder #@db.setter def __ndb_set(self, value): "Stop accidentally replacing the ndb object" string = "Cannot assign directly to ndb object! " string += "Use ndb.attr=value instead." raise Exception(string) #@db.deleter def __ndb_del(self): "Stop accidental deletion." raise Exception("Cannot delete the ndb object!") ndb = property(__ndb_get, __ndb_set, __ndb_del)