ALPreferenceManager

NAOqi Core - Overview | API

What it does

ALPreferenceManager allows managing the robot preferences.

Robot preferences are used to store, among other, all the settings for the applications running on the robot.

How it works

Storage

Robot preferences are stored in a database, both on the robot and on the Aldebaran Cloud; ALPreferenceManager ensures the consistency between the different copies.

Format

A preference is defined by its:

  • Domain: it can be the name of the application using the preference setting.
  • Name: it is the name of the setting.
  • Value. Only string value are currently supported.

For instance, if you are developing a chess application, you could have the following preferences:

  • Domain: “com.aldebaran.apps.chess”
  • Name: “/game/level/default”
  • Value: “medium”

Performances and limitations

Storage

  • On the robot the preferences are stored in an SQLite database under path:

    /home/nao/.local/share/PreferenceManager/prefs.db

    Warning

    Do not to modify this file directly, it must be consistent with the copy of the preferences stored in the Cloud.

  • The preferences are synchronized and saved in the Aldebaran Cloud only if the robot is associated to an Aldebaran user account. If not, preferences are only be stored locally.

    For further details, see: Registering your NAO.

Forbidden characters

To define values:

  • Use alphanumeric characters only,
  • Do not use ‘\’.

Example of use

import sys
import time
from naoqi *

NAO_IP = "nao.local"

Dummy = None
memory = None

# Create a dummy module, just to subscribe to events emitted by PreferenceManager
class DummyModule(ALModule):
    """ Dummy module """
    def __init__(self, name):
        ALModule.__init__(self, name)
        global memory
        memory = ALProxy("ALMemory")
        memory.subscribeToMicroEvent("preferenceAdded", "Dummy", "", "onPreferenceAdded")
        memory.subscribeToMicroEvent("preferenceChanged", "Dummy", "", "onPreferenceChanged")
        memory.subscribeToMicroEvent("preferenceRemoved", "Dummy", "", "onPreferenceRemoved")
        memory.subscribeToMicroEvent("preferenceDomainRemoved", "Dummy", "", "onPreferenceDomainRemoved")
    def onPreferenceAdded(self, event, value, message):
        print "Preference added: " + str(value)
    def onPreferenceChanged(self, event, value, message):
        print "Preference changed: " + str(value)
    def onPreferenceRemoved(self, event, value, message):
        print "Preference removed: " + str(value)
    def onPreferenceDomainRemoved(self, event, value, message):
        print "Preference domain removed: " + str(value)

def main():
    myBroker = ALBroker("myBroker", "0.0.0.0", 0, NAO_IP, 9559)

    global Dummy
    Dummy = DummyModule("Dummy")

    # Play with preference manager
    pm = ALProxy("ALPreferenceManager")
    pm.setValue("com.apps.chess", "level", "hard")
    pm.setValue("com.apps.chess", "treedepth", "10")
    pm.setValue("foo.bar", "foo", "bar")
    pm.setValue("com.apps.chess", "level", "easy")
    print "com.apps.chess - level: " + pm.getValue("com.apps.chess", "level")
    pm.removeValue("foo.bar", "foo")
    pm.removeDomainValues("com.apps.chess")
    print "com.apps.chess - level: " + str(pm.getValue("com.apps.chess", "level"))

    time.sleep(1)
    myBroker.shutdown()
    sys.exit(0)

if __name__ == "__main__":
    main()
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