97 lines
3.7 KiB
Python
97 lines
3.7 KiB
Python
# _*_ coding: utf-8 _*_
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"""
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python_spider.py by xianhu
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"""
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import urllib.error
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import urllib.parse
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import urllib.request
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import http.cookiejar
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# 首先定义下边可能需要的变量
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url = "https://www.baidu.com"
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headers = {"User-Agent": "Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)"}
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# 最简单的网页抓取方式
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response = urllib.request.urlopen(url, timeout=10)
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html = response.read().decode("utf-8")
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# 使用Request实例代替url
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request = urllib.request.Request(url, data=None, headers={})
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response = urllib.request.urlopen(request, timeout=10)
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# 发送数据,即在Request()中添加data参数
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data = urllib.parse.urlencode({"act": "login", "email": "xianhu@qq.com", "password": "123456"})
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request1 = urllib.request.Request(url, data=data) # POST方法
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request2 = urllib.request.Request(url+"?%s" % data) # GET方法
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response = urllib.request.urlopen(request, timeout=10)
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# 发送Header,即在Request()中添加headers参数
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request = urllib.request.Request(url, data=data, headers=headers) # 参数中添加header参数
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request.add_header("Referer", "http://www.baidu.com") # 另一种添加header的方式,添加Referer是为了应对"反盗链"
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response = urllib.request.urlopen(request, timeout=10)
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# 网页抓取引发异常:urllib.error.HTTPError, urllib.error.URLError, 两者存在继承关系
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try:
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urllib.request.urlopen(request, timeout=10)
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except urllib.error.HTTPError as e:
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print(e.code, e.reason)
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except urllib.error.URLError as e:
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print(e.errno, e.reason)
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# 使用代理,以防止IP被封或IP次数受限:
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proxy_handler = urllib.request.ProxyHandler(proxies={"http": "111.123.76.12:8080"})
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opener = urllib.request.build_opener(proxy_handler) # 利用代理创建opener实例
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response = opener.open(url) # 直接利用opener实例打开url
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urllib.request.install_opener(opener) # 安装全局opener,然后利用urlopen打开url
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response = urllib.request.urlopen(url)
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# 使用cookie和cookiejar,应对服务器检查
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cookie_jar = http.cookiejar.CookieJar()
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cookie_jar_handler = urllib.request.HTTPCookieProcessor(cookiejar=cookie_jar)
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opener = urllib.request.build_opener(cookie_jar_handler)
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response = opener.open(url)
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# 发送在浏览器中获取的cookie,两种方式:
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# (1)直接放到headers里
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headers = {
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"User-Agent": "Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)",
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"Cookie": "PHPSESSID=btqkg9amjrtoeev8coq0m78396; USERINFO=n6nxTHTY%2BJA39z6CpNB4eKN8f0KsYLjAQTwPe%2BhLHLruEbjaeh4ulhWAS5RysUM%2B; "
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}
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request = urllib.request.Request(url, headers=headers)
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# (2)构建cookie,添加到cookiejar中
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cookie = http.cookiejar.Cookie(name="xx", value="xx", domain="xx", ...)
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cookie_jar.set_cookie(cookie)
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response = opener.open(url)
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# 同时使用代理和cookiejar
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opener = urllib.request.build_opener(cookie_jar_handler)
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opener.add_handler(proxy_handler)
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response = opener.open("https://www.baidu.com/")
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# 抓取网页中的图片:同样适用于抓取网络上的文件。右击鼠标,找到图片属性中的地址,然后进行保存。
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response = urllib.request.urlopen("http://ww3.sinaimg.cn/large/7d742c99tw1ee7dac2766j204q04qmxq.jpg", timeout=120)
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with open("test.jpg", "wb") as file_img:
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file_img.write(response.read())
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# HTTP认证:即HTTP身份验证
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password_mgr = urllib.request.HTTPPasswordMgrWithDefaultRealm() # 创建一个PasswordMgr
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password_mgr.add_password(realm=None, uri=url, user='username', passwd='password') # 添加用户名和密码
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handler = urllib.request.HTTPBasicAuthHandler(password_mgr) # 创建HTTPBasicAuthHandler
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opener = urllib.request.build_opener(handler) # 创建opner
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response = opener.open(url, timeout=10) # 获取数据
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