Python3中使用urllib的方法详解(header,代理,超时,认证,异常处理)

我们可以利用urllib来抓取远程的数据进行保存哦，以下是python3 抓取网页资源的多种方法，有需要的可以参考借鉴。

1、最简单

    import urllib.request
    response = urllib.request.urlopen('http://python.org/')
    html = response.read()

2、使用 Request

    import urllib.request
    req = urllib.request.Request('http://python.org/')
    response = urllib.request.urlopen(req)
    the_page = response.read()

3、发送数据

    #! /usr/bin/env python3
    import urllib.parse
    import urllib.request
    url = 'http://localhost/login.php'
    user_agent = 'Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)'
    values = {
    'act' : 'login',
    'login[email]' : 'yzhang@i9i8.com',
    'login[password]' : '123456'
    }
    data = urllib.parse.urlencode(values)
    req = urllib.request.Request(url, data)
    req.add_header('Referer', 'http://www.python.org/')
    response = urllib.request.urlopen(req)
    the_page = response.read()
    print(the_page.decode("utf8"))

4、发送数据和header

    #! /usr/bin/env python3
    import urllib.parse
    import urllib.request
    url = 'http://localhost/login.php'
    user_agent = 'Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)'
    values = {
    'act' : 'login',
    'login[email]' : 'yzhang@i9i8.com',
    'login[password]' : '123456'
    }
    headers = { 'User-Agent' : user_agent }
    data = urllib.parse.urlencode(values)
    req = urllib.request.Request(url, data, headers)
    response = urllib.request.urlopen(req)
    the_page = response.read()
    print(the_page.decode("utf8"))

5、http 错误

    #! /usr/bin/env python3
    import urllib.request
    req = urllib.request.Request('http://www.jb51.net ')
    try:
    urllib.request.urlopen(req)
    except urllib.error.HTTPError as e:
    print(e.code)
    print(e.read().decode("utf8"))

6、异常处理1

    #! /usr/bin/env python3
    from urllib.request import Request, urlopen
    from urllib.error import URLError, HTTPError
    req = Request("http://www.jb51.net /")
    try:
    response = urlopen(req)
    except HTTPError as e:
    print('The server couldn't fulfill the request.')
    print('Error code: ', e.code)
    except URLError as e:
    print('We failed to reach a server.')
    print('Reason: ', e.reason)
    else:
    print("good!")
    print(response.read().decode("utf8"))

7、异常处理2

    #! /usr/bin/env python3
    from urllib.request import Request, urlopen
    from urllib.error import URLError
    req = Request("http://www.jb51.net /")
    try:
    response = urlopen(req)
    except URLError as e:
    if hasattr(e, 'reason'):
    print('We failed to reach a server.')
    print('Reason: ', e.reason)
    elif hasattr(e, 'code'):
    print('The server couldn't fulfill the request.')
    print('Error code: ', e.code)
    else:
    print("good!")
    print(response.read().decode("utf8"))

8、HTTP 认证

    #! /usr/bin/env python3
    import urllib.request
    # create a password manager
    password_mgr = urllib.request.HTTPPasswordMgrWithDefaultRealm()
    # Add the username and password.
    # If we knew the realm, we could use it instead of None.
    top_level_url = "https://www.jb51.net /"
    password_mgr.add_password(None, top_level_url, 'rekfan', 'xxxxxx')
    handler = urllib.request.HTTPBasicAuthHandler(password_mgr)
    # create "opener" (OpenerDirector instance)
    opener = urllib.request.build_opener(handler)
    # use the opener to fetch a URL
    a_url = "https://www.jb51.net /"
    x = opener.open(a_url)
    print(x.read())
    # Install the opener.
    # Now all calls to urllib.request.urlopen use our opener.
    urllib.request.install_opener(opener)
    a = urllib.request.urlopen(a_url).read().decode('utf8')
    print(a)

9、使用代理

    #! /usr/bin/env python3
    import urllib.request
    proxy_support = urllib.request.ProxyHandler({'sock5': 'localhost:1080'})
    opener = urllib.request.build_opener(proxy_support)
    urllib.request.install_opener(opener)

    a = urllib.request.urlopen("http://www.jb51.net ").read().decode("utf8")
    print(a)

10、超时

    #! /usr/bin/env python3
    import socket
    import urllib.request
    # timeout in seconds
    timeout = 2
    socket.setdefaulttimeout(timeout)
    # this call to urllib.request.urlopen now uses the default timeout
    # we have set in the socket module
    req = urllib.request.Request('http://www.jb51.net /')
    a = urllib.request.urlopen(req).read()
    print(a)

总结

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