1
2
3 """
4 The Blender.Registry submodule.
5
6 B{New}: L{GetKey} and L{SetKey} have been updated to save and load scripts
7 *configuration data* to files.
8
9 Registry
10 ========
11
12 This module provides a way to create, retrieve and edit B{persistent data} in
13 Blender.
14
15 When a script is executed it has its own private global dictionary,
16 which is deleted when the script exits. This is done to avoid problems with
17 name clashes and garbage collecting. But because of this, the data created by
18 a script isn't kept after it leaves: the data is not persistent. The Registry
19 module was created to give programmers a way around this limitation.
20
21 Possible uses:
22 - saving arbitrary data from a script that itself or another one will need
23 to access later.
24 - saving configuration data for a script: users can view and edit this data
25 using the "Scripts Configuration Editor" script.
26 - saving the current state of a script's GUI (its button values) to restore it
27 when the script is executed again.
28
29 Example::
30
31 import Blender
32 from Blender import Registry
33
34 # this function updates the Registry when we need to:
35 def update_Registry():
36 d = {}
37 d['myvar1'] = myvar1
38 d['myvar2'] = myvar2
39 d['mystr'] = mystr
40 # cache = True: data is also saved to a file
41 Blender.Registry.SetKey('MyScript', d, True)
42
43 # first declare global variables that should go to the Registry:
44 myvar1 = 0
45 myvar2 = 3.2
46 mystr = "hello"
47
48 # then check if they are already there (saved on a
49 # previous execution of this script):
50 rdict = Registry.GetKey('MyScript', True) # True to check on disk also
51 if rdict: # if found, get the values saved there
52 try:
53 myvar1 = rdict['myvar1']
54 myvar2 = rdict['myvar2']
55 mystr = rdict['mystr']
56 except: update_Registry() # if data isn't valid rewrite it
57
58 # ...
59 # here goes the main part of the script ...
60 # ...
61
62 # if at some point the data is changed, we update the Registry:
63 update_Registry()
64
65 @note: In Python terms, the Registry holds a dictionary of dictionaries.
66 Technically any Python or BPython object can be stored: there are no
67 restrictions, but ...
68
69 @note: We have a few recommendations:
70
71 Data saved to the Registry is kept in memory, so if you decide to store large
72 amounts your script users should be clearly informed about it --
73 always keep in mind that you have no idea about their resources and the
74 applications they are running at a given time (unless you are the only
75 user), so let them decide.
76
77 There are restrictions to the data that gets automatically saved to disk by
78 L{SetKey}(keyname, dict, True): this feature is only meant for simple data
79 (bools, ints, floats, strings and dictionaries or sequences of these types).
80
81 For more demanding needs, it's of course trivial to save data to another
82 file or to a L{Blender Text<Text>}.
83 """
84
86 """
87 Get all keys currently in the Registry's dictionary.
88 """
89
90 -def GetKey (key, cached = False):
91 """
92 Get key 'key' from the Registry.
93 @type key: string
94 @param key: a key from the Registry dictionary.
95 @type cached: bool
96 @param cached: if True and the requested key isn't already loaded in the
97 Registry, it will also be searched on the user or default scripts config
98 data dir (config subdir in L{Blender.Get}('datadir')).
99 @return: the dictionary called 'key'.
100 """
101
102 -def SetKey (key, dict, cache = False):
103 """
104 Store a new entry in the Registry.
105 @type key: string
106 @param key: the name of the new entry, tipically your script's name.
107 @type dict: dictionary
108 @param dict: a dict with all data you want to save in the Registry.
109 @type cache: bool
110 @param cache: if True the given key data will also be saved as a file
111 in the config subdir of the scripts user or default data dir (see
112 L{Blender.Get}).
113 @warn: as stated in the notes above, there are restrictions to what can
114 be automatically stored in config files.
115 """
116
118 """
119 Remove the dictionary with key 'key' from the Registry.
120 @type key: string
121 @param key: the name of an existing Registry key.
122 """
123