flags_await: start refactoring

17-futures/countries/flags_await.py

@@ -0,0 +1,48 @@
+"""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
+
+"""
+# BEGIN FLAGS_ASYNCIO
+import asyncio
+
+import aiohttp  # <1>
+
+from flags import BASE_URL, save_flag, show, main  # <2>
+
+
+@asyncio.coroutine  # <3>
+def get_flag(cc):
+    url = '{}/{cc}/{cc}.gif'.format(BASE_URL, cc=cc.lower())
+    resp = yield from aiohttp.request('GET', url)  # <4>
+    image = yield from resp.read()  # <5>
+    return image
+
+
+@asyncio.coroutine
+def download_one(cc):  # <6>
+    image = yield from get_flag(cc)  # <7>
+    show(cc)
+    save_flag(image, cc.lower() + '.gif')
+    return cc
+
+
+def download_many(cc_list):
+    loop = asyncio.get_event_loop()  # <8>
+    to_do = [download_one(cc) for cc in sorted(cc_list)]  # <9>
+    wait_coro = asyncio.wait(to_do)  # <10>
+    res, _ = loop.run_until_complete(wait_coro)  # <11>
+    loop.close() # <12>
+
+    return len(res)
+
+
+if __name__ == '__main__':
+    main(download_many)
+# END FLAGS_ASYNCIO