feat: event support in component_vue for calling python callbacks.

Argument like 'event_foo' will be available as the function foo
in the vue template.

solara/components/component_vue.py

@@ -12,20 +12,35 @@
 P = typing_extensions.ParamSpec("P")
 
 
-def _widget_from_signature(name, base_class: Type[widgets.Widget], func: Callable[..., None]) -> Type[widgets.Widget]:
-    traits = {}
+def _widget_from_signature(classname, base_class: Type[widgets.Widget], func: Callable[..., None], event_prefix: str) -> Type[widgets.Widget]:
+    classprops = {}
 
     parameters = inspect.signature(func).parameters
     for name, param in parameters.items():
+        if name.startswith("event_"):
+            event_name = name[6:]
+
+            def event_handler(self, data, buffers=None, event_name=event_name):
+                callback = self._event_callbacks.get(event_name)
+                if callback:
+                    if buffers:
+                        callback(data, buffers)
+                    else:
+                        callback(data)
+
+            classprops[f"vue_{event_name}"] = event_handler
         if name.startswith("on_") and name[3:] in parameters:
             # callback, will be handled by reacton
             continue
         if param.default == inspect.Parameter.empty:
             trait = traitlets.Any()
         else:
             trait = traitlets.Any(default_value=param.default)
-        traits[name] = trait.tag(sync=True, **widgets.widget_serialization)
-    widget_class = type(name, (base_class,), traits)
+        classprops[name] = trait.tag(sync=True, **widgets.widget_serialization)
+    # maps event_foo to a callable
+    classprops["_event_callbacks"] = traitlets.Dict(default_value={})
+
+    widget_class = type(classname, (base_class,), classprops)
     return widget_class
 
 
@@ -38,7 +53,7 @@ class VueWidgetSolara(vue.VueTemplate):
             template_file = (inspect.getfile(func), vue_path)
 
         base_class = VuetifyWidgetSolara if vuetify else VueWidgetSolara
-        widget_class = _widget_from_signature("VueWidgetSolaraSub", base_class, func)
+        widget_class = _widget_from_signature("VueWidgetSolaraSub", base_class, func, "vue_")
 
         return widget_class
 
@@ -57,6 +72,9 @@ def component_vue(vue_path: str, vuetify=True) -> Callable[[Callable[P, None]],
     are assumed by refer to the same vue property, with `on_foo` being the event handler when `foo` changes from
     the vue template.
 
+    Arguments or the form `event_foo` should be callbacks that can be called from the vue template. They are
+    available as the function `foo` in the vue template.
+
     [See the vue v2 api](https://v2.vuejs.org/v2/api/) for more information on how to use Vue, like `watch`,
     `methods` and lifecycle hooks such as `mounted` and `destroyed`.
 
@@ -73,6 +91,14 @@ def decorator(func: Callable[P, None]):
         VueWidgetSolaraSub = _widget_vue(vue_path, vuetify=vuetify)(func)
 
         def wrapper(*args, **kwargs):
+            event_callbacks = {}
+            kwargs = kwargs.copy()
+            # take out all events named like event_foo and put them in a separate dict
+            for name in list(kwargs):
+                if name.startswith("event_"):
+                    event_callbacks[name[6:]] = kwargs.pop(name)
+            if event_callbacks:
+                kwargs["_event_callbacks"] = event_callbacks
             return VueWidgetSolaraSub.element(*args, **kwargs)  # type: ignore
 
         return wrapper

solara/website/pages/examples/general/mycard.vue

@@ -18,7 +18,7 @@
         <v-divider></v-divider>
 
         <v-card-actions class="justify-center">
-            <v-btn block text>
+            <v-btn block text @click="goto_report">
                 Go to Report
             </v-btn>
         </v-card-actions>

solara/website/pages/examples/general/vue_component.py

@@ -11,6 +11,8 @@
 
 """
 
+from typing import Callable
+
 import numpy as np
 
 import solara
@@ -20,6 +22,7 @@
 
 @solara.component_vue("mycard.vue")
 def MyCard(
+    event_goto_report: Callable[[dict], None],
     value=[1, 10, 30, 20, 3],
     caption="My Card",
     color="red",
@@ -31,11 +34,18 @@ def MyCard(
 def Page():
     gen = np.random.RandomState(seed=seed.value)
     sales_data = np.floor(np.cumsum(gen.random(7) - 0.5) * 100 + 100)
+    show_report = solara.use_reactive(False)
+
     with solara.Column(style={"min-width": "600px"}):
+        if show_report.value:
+            with solara.Card("Report"):
+                solara.Markdown("Lorum ipsum dolor sit amet")
+                solara.Button("Go back", on_click=lambda: show_report.set(False))
+        else:
 
-        def new_seed():
-            seed.value = np.random.randint(0, 100)
+            def new_seed():
+                seed.value = np.random.randint(0, 100)
 
-        solara.Button("Generate new data", on_click=new_seed)
+            solara.Button("Generate new data", on_click=new_seed)
 
-        MyCard(value=sales_data.tolist(), color="green", caption="Sales Last 7 Days")
+            MyCard(value=sales_data.tolist(), color="green", caption="Sales Last 7 Days", event_goto_report=lambda data: show_report.set(True))

tests/unit/component_frontend_test.py

@@ -32,3 +32,19 @@ def ComponentVueTest(value: int, on_value=None):
     mock.assert_called_once_with(2)
     widget.value = 3
     mock.assert_called_with(3)
+
+
+def test_component_vue_event():
+    mock = unittest.mock.Mock()
+
+    @solara._component_vue("component_vue_test.vue")
+    def ComponentVueTest(event_foo=None):
+        pass
+
+    box, rc = solara.render(ComponentVueTest(event_foo=mock), handle_error=False)
+    widget = box.children[0]
+    mock.assert_not_called()
+    widget._handle_event(None, {"event": "foo", "data": 42}, None)
+    mock.assert_called_once_with(42)
+    widget._handle_event(None, {"event": "foo", "data": 42}, [b"bar"])
+    mock.assert_called_with(42, [b"bar"])