Python利用Requests库写爬虫（一）

http://www.jianshu.com/p/e1f8b690b951

基本Get请求：
#-*- coding:utf-8 -*-import requestsurl = 'http://www.baidu.com'r = requests.get(url)print r.text
带参数Get请求：
#-*- coding:utf-8 -*-import requestsurl = 'http://www.baidu.com'payload = {'key1': 'value1', 'key2': 'value2'}r = requests.get(url, params=payload)print r.text
POST请求模拟登陆及一些返回对象的方法：
#-*- coding:utf-8 -*-import requestsurl1 = 'http://www.exanple.com/login'#登陆地址url2 = "http://www.example.com/main"#需要登陆才能访问的地址data={"user":"user","password":"pass"}headers = { "Accept":"text/html,application/xhtml+xml,application/xml;",            "Accept-Encoding":"gzip",            "Accept-Language":"zh-CN,zh;q=0.8",            "Referer":"http://www.example.com/",            "User-Agent":"Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.90 Safari/537.36"            }res1 = requests.post(url1, data=data, headers=headers)res2 = requests.get(url2, cookies=res1.cookies, headers=headers)print res2.content#获得二进制响应内容print res2.raw#获得原始响应内容,需要stream=Trueprint res2.raw.read(50)print type(res2.text)#返回解码成unicode的内容print res2.urlprint res2.history#追踪重定向print res2.cookiesprint res2.cookies['example_cookie_name']print res2.headersprint res2.headers['Content-Type']print res2.headers.get('content-type')print res2.json#讲返回内容编码为jsonprint res2.encoding#返回内容编码print res2.status_code#返回http状态码print res2.raise_for_status()#返回错误状态码
使用Session()对象的写法（Prepared Requests）:
#-*- coding:utf-8 -*-import requestss = requests.Session()url1 = 'http://www.exanple.com/login'#登陆地址url2 = "http://www.example.com/main"#需要登陆才能访问的地址data={"user":"user","password":"pass"}headers = { "Accept":"text/html,application/xhtml+xml,application/xml;",            "Accept-Encoding":"gzip",            "Accept-Language":"zh-CN,zh;q=0.8",            "Referer":"http://www.example.com/",            "User-Agent":"Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.90 Safari/537.36"            }prepped1 = requests.Request('POST', url1,    data=data,    headers=headers).prepare()s.send(prepped1)'''也可以这样写res = requests.Request('POST', url1,data=data,headers=headers)prepared = s.prepare_request(res)# do something with prepped.body# do something with prepped.headerss.send(prepared)'''prepare2 = requests.Request('POST', url2,    headers=headers).prepare()res2 = s.send(prepare2)print res2.content
另一种写法 :
#-*- coding:utf-8 -*-import requestss = requests.Session()url1 = 'http://www.exanple.com/login'#登陆地址url2 = "http://www.example.com/main"#需要登陆才能访问的页面地址data={"user":"user","password":"pass"}headers = { "Accept":"text/html,application/xhtml+xml,application/xml;",            "Accept-Encoding":"gzip",            "Accept-Language":"zh-CN,zh;q=0.8",            "Referer":"http://www.example.com/",            "User-Agent":"Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.90 Safari/537.36"            }res1 = s.post(url1, data=data)res2 = s.post(url2)print(resp2.content)
SessionApi
其他的一些请求方式
>>> r = requests.put("http://httpbin.org/put")>>> r = requests.delete("http://httpbin.org/delete")>>> r = requests.head("http://httpbin.org/get")>>> r = requests.options("http://httpbin.org/get")
遇到的问题:
在cmd下执行，遇到个小错误:
UnicodeEncodeError:'gbk' codec can't encode character u'\xbb' in   position 23460: illegal multibyte sequence
分析:
1、Unicode是编码还是解码
UnicodeEncodeError
很明显是在编码的时候出现了错误
2、用了什么编码
'gbk' codec can't encode character
使用GBK编码出错
解决办法：
确定当前字符串，比如
#-*- coding:utf-8 -*-import requestsurl = 'http://www.baidu.com'r = requests.get(url)print r.encoding>utf-8
已经确定html的字符串是utf-8的，则可以直接去通过utf-8去编码。
print r.text.encode('utf-8')


作者：Jelvis
链接：http://www.jianshu.com/p/e1f8b690b951
來源：简书
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