Add a way to fetch the functions for a given event on a router (#134)

docs/abc.rst

@@ -195,7 +195,7 @@ experimental APIs without issue.
         For this situation, you can pass ``data=b""``.
 
 
-        .. versionchanged:: 4.12
+        .. versionchanged:: 4.2.0
             Added *content_type*.
 
 

docs/changelog.rst

@@ -1,6 +1,18 @@
 Changelog
 =========
 
+5.0.0
+-----
+
+- Add :meth:`gidgethub.routing.Router.fetch` for obtaining a frozenset of functions
+  registered to the router that the event would be called on.
+  (`Issue #74 <https://github.com/brettcannon/gidgethub/issues/74>`_).
+- Make router callback execution order non-deterministic to avoid relying on
+   registration order.
+   (`Issue #74 <https://github.com/brettcannon/gidgethub/issues/74>`_).
+- Fix mypy errors in ``gidgethub.httpx.GitHubAPI._request``
+  (`Issue #133 <https://github.com/brettcannon/gidgethub/issues/133>`_).
+
 4.2.0
 -----
 
@@ -10,7 +22,6 @@ Changelog
   by default the data will be parsed as JSON, and the "application/json" content
   type will be used. (`Issue #115 <https://github.com/brettcannon/gidgethub/issues/115>`_).
 
-
 4.1.1
 -----
 

docs/routing.rst

@@ -73,6 +73,15 @@ in user code.
                 ...
 
 
+    .. method:: fetch(event)
+
+        Return a frozenset of asynchronous callbacks registered
+        to the router that the *event* would be called on. The *event*
+        argument corresponds to :class:`gidgethub.sansio.Event`.
+
+        .. versionadded:: 5.0.0
+
+
     .. coroutine:: dispatch(event, *args, **kwargs)
 
         Call the appropriate asynchronous callbacks for the *event*.
@@ -81,3 +90,6 @@ in user code.
 
         .. versionchanged:: 2.4
             Added ``*args`` and ``**kwargs``.
+
+        .. versionchanged:: 5.0.0
+            Execution order is non-deterministic.

gidgethub/httpx.py

@@ -16,7 +16,7 @@ async def _request(
     ) -> Tuple[int, Mapping[str, str], bytes]:
         """Make an HTTP request."""
         response = await self._client.request(
-            method, url, headers=dict(headers), data=body
+            method, url, headers=dict(headers), content=body
         )
         return response.status_code, response.headers, response.content
 

gidgethub/routing.py

@@ -1,4 +1,4 @@
-from typing import Any, Awaitable, Callable, Dict, List, Optional
+from typing import Any, Awaitable, Callable, Dict, List, FrozenSet
 
 from . import sansio
 
@@ -35,7 +35,6 @@ def add(self, func: AsyncCallback, event_type: str, **data_detail: Any) -> None:
         key of the data in the event being dispatched.
         """
         if len(data_detail) > 1:
-            msg = ()
             raise TypeError(
                 "dispatching based on data details is only "
                 "supported up to one level deep; "
@@ -62,12 +61,12 @@ def decorator(func: AsyncCallback) -> AsyncCallback:
 
         return decorator
 
-    async def dispatch(self, event: sansio.Event, *args: Any, **kwargs: Any) -> None:
-        """Dispatch an event to all registered function(s)."""
-
-        found_callbacks = []
+    def fetch(self, event: sansio.Event) -> FrozenSet[AsyncCallback]:
+        """Return a set of function(s) registered to the router that the event would
+        be called on."""
+        found_callbacks = set()
         try:
-            found_callbacks.extend(self._shallow_routes[event.event])
+            found_callbacks.update(self._shallow_routes[event.event])
         except KeyError:
             pass
         try:
@@ -79,6 +78,12 @@ async def dispatch(self, event: sansio.Event, *args: Any, **kwargs: Any) -> None
                 if data_key in event.data:
                     event_value = event.data[data_key]
                     if event_value in data_values:
-                        found_callbacks.extend(data_values[event_value])
+                        found_callbacks.update(data_values[event_value])
+        return frozenset(found_callbacks)
+
+    async def dispatch(self, event: sansio.Event, *args: Any, **kwargs: Any) -> None:
+        """Dispatch an event to all registered function(s)."""
+
+        found_callbacks = self.fetch(event)
         for callback in found_callbacks:
             await callback(event, *args, **kwargs)

pyproject.toml

@@ -32,7 +32,7 @@ dev = ["aiohttp", "black", "coverage[toml]>=5.0.3", "httpx", "mypy", "pytest-cov
        "pytest-xdist", "tornado"]
 aiohttp = ["aiohttp"]
 tornado = ["tornado"]
-httpx = ["httpx>=0.11.0"]
+httpx = ["httpx>=0.16.1"]
 
 [tool.flit.metadata.urls]
 Documentation = "https://gidgethub.readthedocs.io"

tests/test_routing.py

@@ -130,3 +130,46 @@ async def test_router_copy():
     await other_router.dispatch(event)
     assert deep_callback.called
     assert shallow_callback.called
+
+
+def test_fetch_callbacks():
+    router = routing.Router()
+    event = sansio.Event(
+        {"action": "opened", "count": 42, "status": "completed"},
+        event="yeah",
+        delivery_id="1234",
+    )
+    callbacks = router.fetch(event)
+    assert not callbacks  # No callbacks registered.
+
+    never_called = Callback()
+    # Wrong event.
+    router.add(never_called.meth, "nope")
+    # Wrong event and data detail.
+    router.add(never_called.meth, "nope", action="new")
+    # Wrong data detail key.
+    router.add(never_called.meth, "yeah", never=42)
+    # Wrong data detail value.
+    router.add(never_called.meth, "yeah", count=-13)
+    callbacks = router.fetch(event)
+    assert not callbacks  # No callbacks found.
+    assert not never_called.called
+
+    shallow_registration_1 = Callback()
+    shallow_registration_2 = Callback()
+    deep_registration_1 = Callback()
+    deep_registration_2 = Callback()
+    router = routing.Router()
+    router.add(shallow_registration_1.meth, "yeah")
+    router.add(shallow_registration_2.meth, "nope")
+    router.add(deep_registration_1.meth, "nope", status="completed")
+    router.add(deep_registration_2.meth, "yeah", count=42)
+    callbacks = router.fetch(event)
+    assert shallow_registration_1.meth in callbacks
+    assert shallow_registration_2.meth not in callbacks
+    assert deep_registration_1.meth not in callbacks
+    assert deep_registration_2.meth in callbacks
+    assert not shallow_registration_1.called
+    assert not shallow_registration_2.called
+    assert not deep_registration_1.called
+    assert not deep_registration_2.called