ch20: renamed directory

20-executors/getflags/flags_asyncio.py

@@ -0,0 +1,47 @@
+#!/usr/bin/env python3
+
+"""Download flags of top 20 countries by population
+
+asyncio + aiottp version
+
+Sample run::
+
+    $ python3 flags_asyncio.py
+    EG VN IN TR RU ID US DE CN MX JP BD NG ET FR BR PH PK CD IR
+    20 flags downloaded in 1.07s
+"""
+# tag::FLAGS_ASYNCIO_TOP[]
+import asyncio
+
+from httpx import AsyncClient  # <1>
+
+from flags import BASE_URL, save_flag, main  # <2>
+
+async def download_one(session: AsyncClient, cc: str):  # <3>
+    image = await get_flag(session, cc)
+    save_flag(image, f'{cc}.gif')
+    print(cc, end=' ', flush=True)
+    return cc
+
+async def get_flag(session: AsyncClient, cc: str) -> bytes:  # <4>
+    url = f'{BASE_URL}/{cc}/{cc}.gif'.lower()
+    resp = await session.get(url, timeout=6.1,
+                                  follow_redirects=True)  # <5>
+    return resp.read()  # <6>
+# end::FLAGS_ASYNCIO_TOP[]
+
+# tag::FLAGS_ASYNCIO_START[]
+def download_many(cc_list: list[str]) -> int:    # <1>
+    return asyncio.run(supervisor(cc_list))      # <2>
+
+async def supervisor(cc_list: list[str]) -> int:
+    async with AsyncClient() as session:         # <3>
+        to_do = [download_one(session, cc)
+                 for cc in sorted(cc_list)]      # <4>
+        res = await asyncio.gather(*to_do)       # <5>
+
+    return len(res)                              # <6>
+
+if __name__ == '__main__':
+    main(download_many)
+# end::FLAGS_ASYNCIO_START[]