Work inside Jupyter's running event loop (#55)

CHANGELOG.md

@@ -2,6 +2,12 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Match pages and `Summary()` load inside Jupyter and other code that already
+  runs an asyncio event loop; they raised `asyncio.run() cannot be called from
+  a running event loop` (#55).
+
 ### Added
 
 - `Series.season(key)` finds a season by year or by ESPNcricinfo's two-year

espncricinfo/match.py

@@ -2,6 +2,7 @@
 
 import asyncio
 import json
+from concurrent.futures import ThreadPoolExecutor
 from datetime import date as _date
 from datetime import datetime as _datetime
 from typing import Any, TypedDict
@@ -50,9 +51,19 @@ async def _async_playwright_fetch(url):
     return json.loads(m.group(1))
 
 
-def _playwright_fetch(url):
-    """Synchronous wrapper around _async_playwright_fetch."""
-    return asyncio.run(_async_playwright_fetch(url))
+def _playwright_fetch(url: str) -> dict[str, Any]:
+    """Synchronous wrapper around _async_playwright_fetch.
+
+    Jupyter and other async callers already run an event loop on this thread,
+    and asyncio.run() refuses to nest inside one, so the fetch then runs on a
+    worker thread with its own loop.
+    """
+    try:
+        asyncio.get_running_loop()
+    except RuntimeError:
+        return asyncio.run(_async_playwright_fetch(url))
+    with ThreadPoolExecutor(max_workers=1) as pool:
+        return pool.submit(lambda: asyncio.run(_async_playwright_fetch(url))).result()
 
 
 def _as_float(record: dict[str, Any] | None, key: str) -> float | None:

tests/test_match.py

@@ -434,3 +434,19 @@ def test_no_toss_leaves_toss_fields_none():
 
 def test_series_id_is_int():
     assert isinstance(_make_match().series_id, int)
+
+
+def test_fetch_works_inside_a_running_event_loop():
+    """Jupyter runs an event loop; asyncio.run() refuses to nest inside it (#55)."""
+    import asyncio
+
+    import espncricinfo.match as match_module
+
+    async def fake_fetch(url):
+        return {"url": url}
+
+    async def notebook_cell():
+        return match_module._playwright_fetch("https://example.invalid/page")
+
+    with patch.object(match_module, "_async_playwright_fetch", fake_fetch):
+        assert asyncio.run(notebook_cell()) == {"url": "https://example.invalid/page"}