renumbering chapters >= 19

21-async/domains/curio/domainlib.py

@@ -0,0 +1,26 @@
+from collections.abc import Iterable, AsyncIterator
+from typing import NamedTuple
+
+from curio import TaskGroup
+import curio.socket as socket
+
+
+class Result(NamedTuple):
+    domain: str
+    found: bool
+
+
+async def probe(domain: str) -> Result:
+    try:
+        await socket.getaddrinfo(domain, None)
+    except socket.gaierror:
+        return Result(domain, False)
+    return Result(domain, True)
+
+
+async def multi_probe(domains: Iterable[str]) -> AsyncIterator[Result]:
+    async with TaskGroup() as group:
+        for domain in domains:
+            await group.spawn(probe, domain)
+        async for task in group:
+            yield task.result