thingsdb · joente · Jun 8, 2020 · Jun 7, 2020 · Jun 8, 2020
diff --git a/sample_lego.py b/sample_lego.py
@@ -1,6 +1,7 @@
 import asyncio
 from thingsdb.client import Client
 from thingsdb.model import Collection, Thing, ThingStrict, Enum
+from thingsdb.util import event
 
 
 class Color(Enum):
@@ -21,6 +22,11 @@ def on_init(self, *args, **kwars):
             color value: {self.color.value}
         ''')
 
+    @event('new-color')
+    def on_new_color(self, color):
+        print(f'brick with id {self.id()} as a new color: {color}')
+
+
 class Lego(Collection):
     bricks = '[Brick]', Brick
 
@@ -41,7 +47,15 @@ async def example():
         await lego.load(client)
 
         # ... now the collection will be watched for 100 seconds
-        await asyncio.sleep(100)
+        while True:
+            await asyncio.sleep(3)
+            if lego and lego.bricks:
+                brick = lego.bricks[0]
+                await brick.emit('new-color', 'RED')
+                break
+            await lego.query('.bricks.push(Brick{});')
+
+        await asyncio.sleep(300)
 
     finally:
         client.close()

diff --git a/thingsdb/model/thing.py b/thingsdb/model/thing.py
@@ -43,6 +43,7 @@ class Thing(ThingHash):
     # will be created. A Collection instance will have `False` as default.
     __AS_TYPE__ = True
 
+    _ev_handlers = dict()
     _props = dict()
     _type_name = None  # Only set when __AS_TYPE__ is True
     _visited = 0  # For build, 0=not visited, 1=new_type, 2=set_type, 3=build
@@ -54,6 +55,7 @@ def __init__(self, collection, id: int):
         collection._register(self)
 
     def __init_subclass__(cls):
+        cls._ev_handlers = {}
         cls._props = {}
         items = {
             k: v for k, v in cls.__dict__.items() if not k.startswith('__')}
@@ -63,6 +65,9 @@ def __init_subclass__(cls):
             if isinstance(val, tuple):
                 prop = cls._props[key] = Prop(*val)
                 delattr(cls, key)
+            elif callable(val) and hasattr(val, '_ev'):
+                cls._ev_handlers[val._ev] = val
+
         if cls.__AS_TYPE__:
             cls._type_name = getattr(cls, '__TYPE_NAME__', cls.__name__)
 
@@ -89,6 +94,16 @@ def unwatch(self):
         collection = self._collection
         return collection._client.unwatch(self._id, scope=collection._scope)
 
+    def emit(self, event, *args):
+        data = {f'd{i}': v for i, v in enumerate(args)}
+        dstr = "".join((f", {k}" for k in data.keys()))
+
+        return self._collection.query(
+            f'thing(id).emit(event{dstr});',
+            id=self._id,
+            event=event,
+            **data)
+
     @checkevent
     def on_init(self, event, data):
         self._job_set(data)
@@ -105,6 +120,14 @@ def on_update(self, event, jobs):
     def on_delete(self):
         self._collection._things.pop(self.id())
 
+    def on_event(self, ev, *args):
+        cls = self.__class__
+        fun = cls._ev_handlers.get(ev)
+        if fun is None:
+            logging.debug(f'no event handler for {ev} on {cls.__name__}')
+            return
+        fun(self, *args)
+
     def on_stop(self):
         logging.warning(f'stopped watching thing {self}')
 
@@ -148,6 +171,9 @@ def _job_del(self, k):
         except AttributeError:
             pass
 
+    def _job_event(self, data):
+        self.on_event(*data)
+
     def _job_remove(self, pair):
         cls = self.__class__
         (k, v), = pair.items()
@@ -270,6 +296,7 @@ def _job_set_type(self, data):
         # Thing jobs
         'add': _job_add,
         'del': _job_del,
+        'event': _job_event,
         'remove': _job_remove,
         'set': _job_set,
         'splice': _job_splice,

diff --git a/thingsdb/util/__init__.py b/thingsdb/util/__init__.py
@@ -1,2 +1,3 @@
 from .convert import convert
 from .fmt import fmt
+from .event import event
diff --git a/thingsdb/util/event.py b/thingsdb/util/event.py
@@ -0,0 +1,12 @@
+"""Decorator for handleing events."""
+
+def event(ev):
+
+    def _event(fun):
+        def wrapper(self, *args):
+            fun(self, *args)
+
+        wrapper._ev = ev
+        return wrapper
+
+    return _event
diff --git a/thingsdb/version.py b/thingsdb/version.py
@@ -1 +1 @@
-__version__ = '0.6.3'
+__version__ = '0.6.4'