Python3.X 抓取网络资源
jopen
11年前
Python 3.X 要使用urllib.request 来抓取网络资源。
最简单的方式:
#coding=utf-8 import urllib.request response = urllib.request.urlopen('http://python.org/') buff = response.read() #显示 html = buff.decode("utf8") response.close() print(html)
使用Request的方式:
#coding=utf-8 import urllib.request req = urllib.request.Request('http://www.voidspace.org.uk') response = urllib.request.urlopen(req) buff = response.read() #显示 the_page = buff.decode("utf8") response.close() print(the_page)
这种方式同样可以用来处理其他URL,例如FTP:
#coding=utf-8 import urllib.request req = urllib.request.Request('ftp://ftp.pku.edu.cn/') response = urllib.request.urlopen(req) buff = response.read() #显示 the_page = buff.decode("utf8") response.close() print(the_page)
使用POST请求:
import urllib.parseimport urllib.requesturl = 'http://www.someserver.com/cgi-bin/register.cgi' values = {'name' : 'Michael Foord', 'location' : 'Northampton', 'language' : 'Python' } data = urllib.parse.urlencode(values) req = urllib.request.Request(url, data) response = urllib.request.urlopen(req) the_page = response.read()
使用GET请求:
import urllib.request import urllib.parse data = {} data['name'] = 'Somebody Here' data['location'] = 'Northampton' data['language'] = 'Python' url_values = urllib.parse.urlencode(data) print(url_values) name=Somebody+Here&language=Python&location=Northampton url = 'http://www.example.com/example.cgi' full_url = url + '?' + url_values data = urllib.request.open(full_url)
添加header:
import urllib.parse import urllib.request url = 'http://www.someserver.com/cgi-bin/register.cgi' user_agent = 'Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)' values = {'name' : 'Michael Foord', 'location' : 'Northampton', 'language' : 'Python' } 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()
错误处理:
req = urllib.request.Request('http://www.pretend_server.org') try: urllib.request.urlopen(req) except urllib.error.URLError as e: print(e.reason)
返回的错误代码:
# Table mapping response codes to messages; entries have the # form {code: (shortmessage, longmessage)}. responses = { 100: ('Continue', 'Request received, please continue'), 101: ('Switching Protocols', 'Switching to new protocol; obey Upgrade header'), 200: ('OK', 'Request fulfilled, document follows'), 201: ('Created', 'Document created, URL follows'), 202: ('Accepted', 'Request accepted, processing continues off-line'), 203: ('Non-Authoritative Information', 'Request fulfilled from cache'), 204: ('No Content', 'Request fulfilled, nothing follows'), 205: ('Reset Content', 'Clear input form for further input.'), 206: ('Partial Content', 'Partial content follows.'), 300: ('Multiple Choices', 'Object has several resources -- see URI list'), 301: ('Moved Permanently', 'Object moved permanently -- see URI list'), 302: ('Found', 'Object moved temporarily -- see URI list'), 303: ('See Other', 'Object moved -- see Method and URL list'), 304: ('Not Modified', 'Document has not changed since given time'), 305: ('Use Proxy', 'You must use proxy specified in Location to access this ' 'resource.'), 307: ('Temporary Redirect', 'Object moved temporarily -- see URI list'), 400: ('Bad Request', 'Bad request syntax or unsupported method'), 401: ('Unauthorized', 'No permission -- see authorization schemes'), 402: ('Payment Required', 'No payment -- see charging schemes'), 403: ('Forbidden', 'Request forbidden -- authorization will not help'), 404: ('Not Found', 'Nothing matches the given URI'), 405: ('Method Not Allowed', 'Specified method is invalid for this server.'), 406: ('Not Acceptable', 'URI not available in preferred format.'), 407: ('Proxy Authentication Required', 'You must authenticate with ' 'this proxy before proceeding.'), 408: ('Request Timeout', 'Request timed out; try again later.'), 409: ('Conflict', 'Request conflict.'), 410: ('Gone', 'URI no longer exists and has been permanently removed.'), 411: ('Length Required', 'Client must specify Content-Length.'), 412: ('Precondition Failed', 'Precondition in headers is false.'), 413: ('Request Entity Too Large', 'Entity is too large.'), 414: ('Request-URI Too Long', 'URI is too long.'), 415: ('Unsupported Media Type', 'Entity body in unsupported format.'), 416: ('Requested Range Not Satisfiable', 'Cannot satisfy request range.'), 417: ('Expectation Failed', 'Expect condition could not be satisfied.'), 500: ('Internal Server Error', 'Server got itself in trouble'), 501: ('Not Implemented', 'Server does not support this operation'), 502: ('Bad Gateway', 'Invalid responses from another server/proxy.'), 503: ('Service Unavailable', 'The server cannot process the request due to a high load'), 504: ('Gateway Timeout', 'The gateway server did not receive a timely response'), 505: ('HTTP Version Not Supported', 'Cannot fulfill request.'), }