Module Registry
source code
The Blender.Registry submodule.
New: GetKey and SetKey have been updated to save and load scripts
*configuration data* to files.
Registry
This module provides a way to create, retrieve and edit
persistent data in Blender.
When a script is executed it has its own private global dictionary,
which is deleted when the script exits. This is done to avoid problems
with name clashes and garbage collecting. But because of this, the
data created by a script isn't kept after it leaves: the data is not
persistent. The Registry module was created to give programmers a way
around this limitation.
Possible uses:
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saving arbitrary data from a script that itself or another one
will need to access later.
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saving configuration data for a script: users can view and edit
this data using the "Scripts Configuration Editor"
script.
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saving the current state of a script's GUI (its button values)
to restore it when the script is executed again.
Example:
import Blender
from Blender import Registry
# this function updates the Registry when we need to:
def update_Registry():
d = {}
d['myvar1'] = myvar1
d['myvar2'] = myvar2
d['mystr'] = mystr
# cache = True: data is also saved to a file
Blender.Registry.SetKey('MyScript', d, True)
# first declare global variables that should go to the Registry:
myvar1 = 0
myvar2 = 3.2
mystr = "hello"
# then check if they are already there (saved on a
# previous execution of this script):
rdict = Registry.GetKey('MyScript', True) # True to check on disk also
if rdict: # if found, get the values saved there
try:
myvar1 = rdict['myvar1']
myvar2 = rdict['myvar2']
mystr = rdict['mystr']
except: update_Registry() # if data isn't valid rewrite it
# ...
# here goes the main part of the script ...
# ...
# if at some point the data is changed, we update the Registry:
update_Registry()
Notes:
-
In Python terms, the Registry holds a dictionary of
dictionaries. Technically any Python or BPython object can be
stored: there are no restrictions, but ...
-
We have a few recommendations:
Data saved to the Registry is kept in memory, so if you decide
to store large amounts your script users should be clearly informed
about it -- always keep in mind that you have no idea about their
resources and the applications they are running at a given time
(unless you are the only user), so let them decide.
There are restrictions to the data that gets automatically saved
to disk by SetKey(keyname, dict, True): this feature is only
meant for simple data (bools, ints, floats, strings and
dictionaries or sequences of these types).
For more demanding needs, it's of course trivial to save data to
another file or to a Blender Text.
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Keys()
Get all keys currently in the Registry's dictionary. |
source code
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Get key 'key' from the Registry.
- Parameters:
key (string) - a key from the Registry dictionary.
cached (bool) - if True and the requested key isn't already loaded in the
Registry, it will also be searched on the user or default scripts
config data dir (config subdir in Blender.Get('datadir')).
- Returns:
- the dictionary called 'key'.
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Store a new entry in the Registry.
- Parameters:
key (string) - the name of the new entry, tipically your script's name.
dict (dictionary) - a dict with all data you want to save in the Registry.
cache (bool) - if True the given key data will also be saved as a file in the
config subdir of the scripts user or default data dir (see Blender.Get).
Warning:
as stated in the notes above, there are restrictions to what can
be automatically stored in config files.
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Remove the dictionary with key 'key' from the Registry.
- Parameters:
key (string) - the name of an existing Registry key.
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