Item configuration: Relative item references about smarthome HOT 7 CLOSED

Suggestion for implementation:

• relative references start with a point (.)
• To reference a level higher, a point has to be added for every level
• relative parts of a path can be added to the point(s).

For instance, if you have an item subtree in the following form:

[level_1]
    [[level_2]]
        [[[item_1]]]
            eval_trigger = 
           [[[[subitem_1]]]]
        [[[item_2]]]
           [[[[subitem_2]]]]

the eval_trigger statement can reference

• level_1.level_2.item_1-> .
• level_1.level_2.item_1.subitem_1 -> .subitem_1
• level_1.level_2-> ..
• level_1.level_2.item_2 -> ..item_2
• level_1.level_2.item_2.subitem_2 -> ..item_2.subitem_2
• level_1-> ...

from smarthome.

This is my current implementation:

        #############################################################
        # Item Attributes
        #############################################################
        for attr, value in config.items():
            if not isinstance(value, dict):
                if attr in ['cycle', 'eval', 'name', 'type', 'value']:
                    setattr(self, '_' + attr, value)
                elif attr in ['cache', 'enforce_updates']:  # cast to bool
                    try:
                        setattr(self, '_' + attr, _cast_bool(value))
                    except:
                        logger.warning("Item '{0}': problem parsing '{1}'.".format(self._path, attr))
                        continue
                elif attr in ['eval_trigger']:  # cast to list
                    ## extend here for two dots '..' which means parent
                    ## this will result in a lot of writing work less when you have 
                    ## an item which is to be triggered by its parent
                    if isinstance(value, str):
                        if value == '..':
                            logger.info("Parsing {0} we found eval_trigger = ..  will be converted to its parent: {1}".format(self.id(), self.id()))
                            value = self.return_parent().id()
                        value = [value, ]
                    setattr(self, '_' + attr, value)
                elif attr in ['crontab']:  # cast to list
                    if isinstance(value, str):
                        value = [value, ]
                    setattr(self, '_' + attr, value)
                elif attr == 'autotimer':
                    time, __, value = value.partition('=')
                    if value is not None:
                        self._autotimer = time, value
                elif attr == 'threshold':
                    low, __, high = value.rpartition(':')
                    if not low:
                        low = high
                    self._threshold = True
                    self.__th_crossed = False
                    self.__th_low = float(low.strip())
                    self.__th_high = float(high.strip())
                    logger.debug("Item {}: set threshold => low: {} high: {}".format(self._path, self.__th_low, self.__th_high))
                else:
                    self.conf[attr] = value

And this is a typical application for it:

                [[[[[Ausfall]]]]]
                    # Ausfall = 1
                    name = Ausfall Stellgröße Heizkreis Windfang
                    visu_acl = rw
                    type = bool
                    knx_dpt = 1
                    knx_init = 5/3/25
                    [[[[[[LastUpdate]]]]]]
                        name = letztes Update von
                        type = foo
                        cache = yes
                        eval = self.return_parent().last_update().strftime('%a %d.%m. %H:%M:%S')
                        eval_trigger = ..

from smarthome.

I am thinking of isolating the conversion itself to a method, which can be used by plugins. The parse_item method of a plugin could call the conversion method to support relative references for the item attributed of the plugin.

from smarthome.

That would be a nice feature.. The autoblind plugin is using this method successfully.

from smarthome.

Feature implementation: PR #94

(German) documentation is here: https://github.com/smarthomeNG/smarthome/wiki/Items:-Relative-Item-Referenzen

from smarthome.

I guess we can close this issue, right?

from smarthome.

Right!

from smarthome.