add git ignore

.gitignore

@@ -0,0 +1,3 @@
+# Python:
+.idea
+__pycache__

utils.py

@@ -18,3 +18,28 @@ def parse_url(url):
     except ConnectionError:
         print('Error.')
     return None
+
+class Downloader(object):
+    """
+    python3.5的标准库自带的async和await指令，
+    相当于3.5之前的 @asyncio.coroutine和yield from
+    提供异步抓取
+    """
+    def __init__(self, urls):
+        self.urls = urls
+        self._htmls = []
+
+    async def download_single_page(self, url):
+        async with aiohttp.ClientSession() as session:
+            async with session.get(url) as resp:
+                self._htmls.append(await resp.text())
+
+    def download(self):
+        loop = asyncio.get_event_loop()
+        tasks = [self.download_single_page(url) for url in self.urls]
+        loop.run_until_complete(asyncio.wait(tasks))
+
+    @property
+    def htmls(self):
+        self.download()
+        return self._htmls