Python的requests网络编程包使用教程

> r = requests.get('http://httpbin.org/get')
> print r.text
{
 "args": {}, 
 "headers": {
  "Accept": "*/*", 
  "Accept-Encoding": "gzip, deflate", 
  "Connection": "close", 
  "Host": "httpbin.org", 
  "User-Agent": "python-requests/2.3.0 CPython/2.6.6 Windows/7", 
  "X-Request-Id": "8a28bbea-55cd-460b-bda3-f3427d66b700"
 }, 
 "origin": "124.192.129.84", 
 "url": "http://httpbin.org/get"
}

 > import requests
> pqyload = {'q':'杨彦星'}
> r = requests.get('http://www.so.com/s',params = pqyload)
> r.url
u'http://www.so.com/s"htmlcode">

 > payload = {'a':'杨','b':'hello'}
> r = requests.post("http://httpbin.org/post", data=payload)
> print r.text
{
 "args": {}, 
 "data": "", 
 "files": {}, 
 "form": {
  "a": "\u6768", 
  "b": "hello"
 }, 
 "headers": {
  "Accept": "*/*", 
  "Accept-Encoding": "gzip, deflate", 
  "Connection": "close", 
  "Content-Length": "19", 
  "Content-Type": "application/x-www-form-urlencoded", 
  "Host": "httpbin.org", 
  "User-Agent": "python-requests/2.3.0 CPython/2.6.6 Windows/7", 
  "X-Request-Id": "c81cb937-04b8-4a2d-ba32-04b5c0b3ba98"
 }, 
 "json": null, 
 "origin": "124.192.129.84", 
 "url": "http://httpbin.org/post"
}
>



可以看到，post参数已经传到了form里,data不光可以接受字典类型的数据，还可以接受json等格式




> payload = {'a':'杨','b':'hello'}
> import json
> r = requests.post('http://httpbin.org/post', data=json.dumps(payload))



五、发送文件的post类型，这个相当于向网站上传一张图片，文档等操作，这时要使用files参数




> url = 'http://httpbin.org/post'
> files = {'file': open('touxiang.png', 'rb')}
> r = requests.post(url, files=files)



定制headers，使用headers参数来传递




> import json
> url = 'https://api.github.com/some/endpoint'
> payload = {'some': 'data'}
> headers = {'content-type': 'application/json'}
> r = requests.post(url, data=json.dumps(payload), headers=headers)



 

六、响应内容

响应状态码：




r = requests.get('http://httpbin.org/get')
print r.status_code



响应头：

 


> print r.headers
{'content-length': '519', 'server': 'gunicorn/18.0', 'connection': 'keep-alive', 'date': 'Sun, 15 Jun 2014 14:19:52 GMT', 'access-control-allow-origin': '*', 'content-type': 'application/json'}



也可以取到这个个别的响应头用来做一些判断，这里的参数是不区分大小写的




r.headers[‘Content-Type']
r.headers.get(‘Content-Type')



响应内容，前面已经在应用了：




r.text
r.content



 

七、获取响应中的cookies




> r = requests.get('http://www.baidu.com')
> r.cookies['BAIDUID']
'D5810267346AEFB0F25CB0D6D0E043E6:FG=1'



也可以自已定义请求的COOKIES




> url = 'http://httpbin.org/cookies'
> cookies = {'cookies_are':'working'}
> r = requests.get(url,cookies = cookies)
> 
> print r.text
{
 "cookies": {
  "cookies_are": "working"
 }
}
>



cookies还有很多，因为目前我也还不是很多，以后再扩充吧


八、使用timeout参数设置超时时间




> requests.get('http://github.com', timeout=1) 
<Response [200]>



如果将时间设置成非常小的数，如


requests.get('http://github.com', timeout=0.001)


，那么如果在timeout的时间内没有连接，那么将会抛出一个Timeout的异常


九、访问中使用session

先初始化一个session对象，


s = requests.Session() 



然后使用这个session对象来进行访问，r = s.post(url,data = user)

以下通过访问人人网来获取首页中的最近来访问，然后再访问查看更多的来访来读取更多的最近来访

更多的来访就是以带session的访问http://www.renren.com/myfoot.do




 #coding:utf-8
import requests
import re
url = r'http://www.renren.com/ajaxLogin'
user = {'email':'email','password':'pass'}
s = requests.Session()
r = s.post(url,data = user)
html = r.text
visit = []
first = re.compile(r'</span><span class="time-tip first-tip"><span class="tip-content">(.*"time-tip"><span class="tip-content">(.*"time-tip last-second-tip"><span class="tip-content">(.*"time-tip last-tip"><span class="tip-content">(.*"name":"(.*"')
visitmore = fm.findall(vm.text)
for i in visitmore:
  print i






十、requests-cookies

Cookies就像字典一样储存了各个项的值并保存起来, 例如我们的用户名, 密码, 登录信息等都可以保存起来. 当网页再次被加载时可以从cookies中找到相关的信息并从而免除再次输入赋值的过程.

在requests中使用get等请求时同样可以赋予cookies信息. 例如我们从浏览器中获取某次网页加载时请求的cookies, 可以同样赋予requests再次使用.

requests请求时加入cookies={key:value}参数即可传递cookies.




import requests
url = 'http://httpbin.org/cookies'
cookies = dict(cookies_are='working')

r = requests.get(url, cookies=cookies)
r.text
#'{"cookies": {"cookies_are": "working"}}'




查询某次请求的cookies很简单, 就像获得headers一样使用cookies属性即可:




url = 'http://example.com/some/cookie/setting/url'
r = requests.get(url)

r.cookies['example_cookie_name']
# 'example_cookie_value'




以下函数可以分解浏览器获得的cookies字符串到一个字典,从而帮助我们模拟requests请求.




def browsercookiesdict(s):
 '''Covert cookies string from browser to a dict'''
 ss=s.split(';')
 outdict={}
 for item in ss:
 i1=item.split('=',1)[0].strip()
 i2=item.split('=',1)[1].strip()
 outdict[i1]=i2
 return outdict