Merge remote-tracking branch 'xianhu/master'

README.md

@@ -1,7 +1,7 @@
 # LearnPython
 以撸代码的形式学习Python, 具体说明在[知乎专栏-撸代码,学知识](https://zhuanlan.zhihu.com/pythoner)
 
-===============================================================================
+===================================================================================================
 ### python_base.py: 千行代码入门Python
 
 ### python_visual.py: 15张图入门Matplotlib
@@ -23,6 +23,12 @@
 ### python_decorator.py: Python进阶: 通过实例详解装饰器（附代码）
 
 ### python_datetime.py: 你真的了解Python中的日期时间处理吗？
-===============================================================================
+
+### python_metaclass.py: Python进阶: 一步步理解Python中的元类metaclass
+
+### python_coroutine.py: Python进阶：理解Python中的异步IO和协程(Coroutine), 并应用在爬虫中
+
+### python_aiohttp.py: Python中最好用的异步爬虫库Aiohttp代码实例
+===================================================================================================
 
 ### 您可以fork该项目,并在修改后提交Pull request

python_aiohttp.py

@@ -0,0 +1,116 @@
+# _*_ coding: utf-8 _*_
+
+"""
+python_aiohttp.py by xianhu
+"""
+
+import asyncio
+import aiohttp
+
+
+# 简单实例
+async def aiohttp_test01(url):
+    async with aiohttp.ClientSession() as session:
+        async with session.get(url) as resp:
+            print(resp.status)
+            print(await resp.text())
+
+loop = asyncio.get_event_loop()
+tasks = [aiohttp_test01("https://api.github.com/events")]
+loop.run_until_complete(asyncio.wait(tasks))
+loop.close()
+
+# 其他Http方法
+# session.post('http://httpbin.org/post', data=b'data')
+# session.put('http://httpbin.org/put', data=b'data')
+# session.delete('http://httpbin.org/delete')
+# session.head('http://httpbin.org/get')
+# session.options('http://httpbin.org/get')
+# session.patch('http://httpbin.org/patch', data=b'data')
+
+# 自定义Headers
+# payload = {'some': 'data'}
+# headers = {'content-type': 'application/json'}
+# await session.post(url, data=json.dumps(payload), headers=headers)
+
+# 自定义Cookie
+# cookies = {'cookies_are': 'working'}
+# async with ClientSession(cookies=cookies) as session:
+# 访问Cookie: session.cookie_jar
+
+# 在URLs中传递参数
+# 1. params = {'key1': 'value1', 'key2': 'value2'}
+# 2. params = [('key', 'value1'), ('key', 'value2')]
+# async with session.get('http://httpbin.org/get', params=params) as resp:
+#     assert resp.url == 'http://httpbin.org/get?key2=value2&key1=value1'
+
+# 发送数据
+# payload = {'key1': 'value1', 'key2': 'value2'}
+# async with session.post('http://httpbin.org/post', data=payload) as resp:
+# async with session.post(url, data=json.dumps(payload)) as resp:
+#     print(await resp.text())
+
+# 发送文件(1)
+# files = {'file': open('report.xls', 'rb')}
+# await session.post(url, data=files)
+
+# 发送数据(2)
+# data = FormData()
+# data.add_field('file',
+#                open('report.xls', 'rb'),
+#                filename='report.xls',
+#                content_type='application/vnd.ms-excel')
+# await session.post(url, data=data)
+
+# 超时设置
+# aync with session.get('https://github.com', timeout=60) as r:
+
+# 代理支持
+# async with aiohttp.ClientSession() as session:
+#     async with session.get("http://python.org", proxy="http://some.proxy.com") as resp:
+#         print(resp.status)
+
+# async with aiohttp.ClientSession() as session:
+#     proxy_auth = aiohttp.BasicAuth('user', 'pass')
+#     async with session.get("http://python.org", proxy="http://some.proxy.com", proxy_auth=proxy_auth) as resp:
+#         print(resp.status)
+# session.get("http://python.org", proxy="http://user:pass@some.proxy.com")
+
+# 返回的内容
+# async with session.get('https://api.github.com/events') as resp:
+#     print(await resp.text())
+#     print(await resp.text(encoding='gbk'))
+#     print(await resp.read())
+#     print(await resp.json())
+
+# 返回内容较大
+# with open(filename, 'wb') as fd:
+#     while True:
+#         chunk = await resp.content.read(chunk_size)
+#         if not chunk:
+#             break
+#         fd.write(chunk)
+
+# 返回的其他变量
+# async with session.get('http://httpbin.org/get') as resp:
+#     print(resp.status)        # 状态码
+#     print(resp.headers)       # Headers
+#     print(resp.raw_headers)   # 原始Headers
+#     print(resp.cookies)       # 返回的Cookie
+
+# 访问历史History
+# resp = await session.get('http://example.com/some/redirect/')
+# resp: <ClientResponse(http://example.com/some/other/url/) [200]>
+# resp.history: (<ClientResponse(http://example.com/some/redirect/) [301]>,)
+
+# 释放返回的Response
+# 1. async with session.get(url) as resp: pass
+# 2. await resp.release()
+
+# 连接器: Connectors
+# conn = aiohttp.TCPConnector()
+# session = aiohttp.ClientSession(connector=conn)
+
+# 限制连接池大小:
+# conn = aiohttp.TCPConnector(limit=30)
+# conn = aiohttp.TCPConnector(limit=None)

python_coroutine.py

@@ -0,0 +1,77 @@
+# _*_ coding: utf-8 _*_
+
+"""
+python_coroutine.py by xianhu
+"""
+
+import asyncio
+import aiohttp
+import threading
+
+
+# 生产者、消费者例子
+def consumer():         # 定义消费者，由于有yeild关键词，此消费者为一个生成器
+    print("[Consumer] Init Consumer ......")
+    r = "init ok"       # 初始化返回结果，并在启动消费者时，返回给生产者
+    while True:
+        n = yield r     # 消费者通过yield关键词接收生产者产生的消息，同时返回结果给生产者
+        print("[Consumer] conusme n = %s, r = %s" % (n, r))
+        r = "consume %s OK" % n     # 消费者消费结果，下个循环返回给生产者
+
+
+def produce(c):         # 定义生产者，此时的 c 为一个生成器
+    print("[Producer] Init Producer ......")
+    r = c.send(None)    # 启动消费者生成器，同时第一次接收返回结果
+    print("[Producer] Start Consumer, return %s" % r)
+    n = 0
+    while n < 5:
+        n += 1
+        print("[Producer] While, Producing %s ......" % n)
+        r = c.send(n)   # 向消费者发送消息，同时准备接收结果。此时会切换到消费者执行
+        print("[Producer] Consumer return: %s" % r)
+    c.close()           # 关闭消费者生成器
+    print("[Producer] Close Producer ......")
+
+# produce(consumer())
+
+
+# 异步IO例子：适配Python3.4，使用asyncio库
+@asyncio.coroutine
+def hello(index):                   # 通过装饰器asyncio.coroutine定义协程
+    print('Hello world! index=%s, thread=%s' % (index, threading.currentThread()))
+    yield from asyncio.sleep(1)     # 模拟IO任务
+    print('Hello again! index=%s, thread=%s' % (index, threading.currentThread()))@asyncio.coroutine
+
+loop = asyncio.get_event_loop()     # 得到一个事件循环模型
+tasks = [hello(1), hello(2)]        # 初始化任务列表
+loop.run_until_complete(asyncio.wait(tasks))    # 执行任务
+loop.close()                        # 关闭事件循环列表
+
+
+# 异步IO例子：适配Python3.5，使用async和await关键字
+async def hello1(index):            # 通过关键字async定义协程
+    print('Hello world! index=%s, thread=%s' % (index, threading.currentThread()))
+    await asyncio.sleep(1)          # 模拟IO任务
+    print('Hello again! index=%s, thread=%s' % (index, threading.currentThread()))
+
+loop = asyncio.get_event_loop()     # 得到一个事件循环模型
+tasks = [hello1(1), hello1(2)]      # 初始化任务列表
+loop.run_until_complete(asyncio.wait(tasks))    # 执行任务
+loop.close()                        # 关闭事件循环列表
+
+
+# aiohttp 实例
+async def get(url):
+    async with aiohttp.ClientSession() as session:
+        async with session.get(url) as resp:
+            print(url, resp.status)
+            print(url, await resp.text())
+
+loop = asyncio.get_event_loop()     # 得到一个事件循环模型
+tasks = [                           # 初始化任务列表
+    get("http://zhushou.360.cn/detail/index/soft_id/3283370"),
+    get("http://zhushou.360.cn/detail/index/soft_id/3264775"),
+    get("http://zhushou.360.cn/detail/index/soft_id/705490")
+]
+loop.run_until_complete(asyncio.wait(tasks))    # 执行任务
+loop.close()                        # 关闭事件循环列表

python_metaclass.py

@@ -0,0 +1,55 @@
+# _*_ coding: utf-8 _*_
+
+"""
+python_metaclass.py by xianhu
+"""
+
+
+class Foo:
+    def hello(self):
+        print("hello world!")
+        return
+
+foo = Foo()
+print(type(foo))            # <class '__main__.Foo'>
+print(type(foo.hello))      # <class 'method'>
+print(type(Foo))            # <class 'type'>
+
+temp = Foo                  # 赋值给其他变量
+Foo.var = 11                # 增加参数
+print(Foo)                  # 作为函数参数
+
+
+# ========================================================================
+def init(self, name):
+    self.name = name
+    return
+
+
+def hello(self):
+    print("hello %s" % self.name)
+    return
+
+Foo = type("Foo", (object,), {"__init__": init, "hello": hello, "cls_var": 10})
+foo = Foo("xianhu")
+print(foo.hello())
+print(Foo.cls_var)
+
+print(foo.__class__)
+print(Foo.__class__)
+print(type.__class__)
+# ========================================================================
+
+
+class Author(type):
+    def __new__(mcs, name, bases, dict):
+        # 添加作者属性
+        dict["author"] = "xianhu"
+        return super(Author, mcs).__new__(mcs, name, bases, dict)
+
+
+class Foo(object, metaclass=Author):
+    pass
+
+foo = Foo()
+print(foo.author)

python_requests.py

@@ -4,7 +4,7 @@
 python_requests.py by xianhu
 """
 
-import requests
+import requests.adapters
 
 # 不同方式获取网页内容, 返回一个Response对象, 请求的参数可以为url或Request对象
 r0 = requests.get("https://github.com/timeline.json")
@@ -181,7 +181,7 @@ requests.get("https://github.com", timeout=(3.05, 27))
 # 若请求超过了设定的最大重定向次数, 则会抛出一个 TooManyRedirects 异常
 # 所有Requests显式抛出的异常都继承自 requests.exceptions.RequestException
 
-# 所有异常
+# 所有异常:
 # exception requests.RequestException(*args, **kwargs): There was an ambiguous exception that occurred while handling your request.
 # exception requests.ConnectionError(*args, **kwargs): A Connection error occurred.
 # exception requests.HTTPError(*args, **kwargs): An HTTP error occurred.
@@ -223,7 +223,7 @@ proxies = {
 requests.get("http://example.org", proxies=proxies)
 # 若代理需要使用HTTP Basic Auth, 可以使用http://user:password@host:port/, 比如"http": "http://user:pass@10.10.1.10:3128/"
 
-# 除了基本的 HTTP 代理, Request 还支持 SOCKS 协议的代理
+# 除了基本的 HTTP 代理, Request 还支持 SOCKS 协议的代理, 此时需要单独安装:
 # $ pip install requests[socks]
 proxies = {
     "http": "socks5://user:pass@host:port",
@@ -231,5 +231,17 @@ proxies = {
 }
 requests.get("http://example.org", proxies=proxies)
 
+# Requests 传输适配器
+# 从 v1.0.0 以后，Requests 的内部采用了模块化设计。部分原因是为了实现传输适配器（Transport Adapter）。
+# 传输适配器提供了一个机制，让你可以为 HTTP 服务定义交互方法。尤其是它允许你应用服务前的配置。
+# Requests 自带了一个传输适配器，也就是 HTTPAdapter。 这个适配器使用了强大的 urllib3，为 Requests 提供了默认的 HTTP 和 HTTPS 交互。
+# 每当 Session 被初始化，就会有适配器附着在 Session 上，其中一个供 HTTP 使用，另一个供 HTTPS 使用。
+# Request 允许用户创建和使用他们自己的传输适配器，实现他们需要的特殊功能。创建好以后，传输适配器可以被加载到一个会话对象上，附带着一个说明，告诉会话适配器应该应用在哪个 web 服务上。
+s = requests.Session()
+s.mount("http://baidu.com", requests.adapters.HTTPAdapter())
+
+# 出现错误: Connection pool is full, discarding connection: xxxx.com
+s.mount('https://', requests.adapters.HTTPAdapter(pool_connections=100, pool_maxsize=100))
+
 # 关闭InsecurePlatformWarning
 # requests.packages.urllib3.disable_warnings()