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Recommend bytes-check to deserialize_dbobjs example

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Griatch 2022-07-14 12:50:01 +02:00
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docs/source/Components/Attributes.md
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@ -325,14 +325,15 @@ values into a string representation before storing it to the database. This is d
### Storing single objects
With a single object, we mean anything that is *not iterable*, like numbers, strings or custom class
instances without the `__iter__` method.
With a single object, we mean anything that is *not iterable*, like numbers,
strings or custom class instances without the `__iter__` method.
* You can generally store any non-iterable Python entity that can be _pickled_.
* Single database objects/typeclasses can be stored, despite them normally not being possible
to pickle. Evennia will convert them to an internal representation using theihr classname,
database-id and creation-date with a microsecond precision. When retrieving, the object
instance will be re-fetched from the database using this information.
* Single database objects/typeclasses can be stored, despite them normally not
being possible to pickle. Evennia will convert them to an internal
representation using theihr classname, database-id and creation-date with a
microsecond precision. When retrieving, the object instance will be re-fetched
from the database using this information.
* If you 'hide' a db-obj as a property on a custom class, Evennia will not be
able to find it to serialize it. For that you need to help it out (see below).
@ -389,13 +390,23 @@ class Container:
def __deserialize_dbobjs__(self):
"""This is called after deserialization and allows you to
restore the 'hidden' dbobjs you serialized before"""
self.mydbobj = dbserialize.dbunserialize(self.mydbobj)
if isinstance(self.mydbobj, bytes):
# make sure to check if it's bytes before trying dbunserialize
self.mydbobj = dbserialize.dbunserialize(self.mydbobj)
# let's assume myobj is a db-object
container = Container(myobj)
obj.db.mydata = container # will now work fine!
```
> Note the extra check in `__deserialize_dbobjs__` to make sure the thing you
> are deserializing is a `bytes` object. This is needed because the Attribute's
> cache reruns deserializations in some situations when the data was already
> once deserialized. If you see errors in the log saying
> `Could not unpickle data for storage: ...`, the reason is
> likely that you forgot to add this check.
### Storing multiple objects
This means storing objects in a collection of some kind and are examples of *iterables*, pickle-able