一、安装
pip install requests
二、初试
import requests
#使用get方法访问百度
r = requests.get('http://www.baidu.com')
#状态码
r.status_code
Out[4]: 200
#设置返回内容的编码格式为utf-8
r.encoding='utf-8'
#显示返回对象的内容
r.text
三、requests库的常用7个方法
| 方法 | 说明 | 备注 |
|---|---|---|
| requests.request() | 构造一个请求,支撑以下各方法 的基础方法 | |
| requests.get() | 获取html页面的主要方法,对应于HTTP的GET | GET:请求获取URL位置的资源 |
| requests.head() | 获取HTML网页头信息的方法,对应于HTTP的HEAD | HEAD:请求获取URL位置资源的响应消息报告,即获得该资源的头部信息 |
| requests.post() | 向网页提交POST请求的方法,对应HTTP的POST | POST:请求向URL位置的资源后附加新的数据 |
| requests.put() | 向网页提交PUT请求的方法,对应HTTP的PUT | PUT:请求向URL位置存储一个资源,覆盖源URL位置的资源 |
| requests.patch() | 向网页提交局部修改请求,对应HTTP的PATCH | 请求局部更新URL位置的资源,即改变该处资源的部分内容 |
| requests.delete() | 向网页提交删除请求,对应HTTP的DELETE | 请求删除URL位置存储的资源 |
注意:put和patch方法的区别
假设URL位置上有一组数据userinfo,包括userid、username等20个字段
需求:用户修改了username,其他不变
采用patch,仅向URL提交username的局部更新请求。
采用put,必须将所有20个字段一并提交到URL,未提交字段被删除
patch的最主要用处:节省网络带宽
3.1 requests.get方法
requests.get(url, params=None, **kwargs)
- url:拟获取页面的URL链接;格式 ---url='http://www.baidu.com'
- params:url中的额外参数,字典或字节流格式,可选
- **kwargs:12个访问控制的参数
url格式 http://host[:port][path]
host:合法的Internet主句域名或IP地址
port:端口后,缺省端口为80
path:请求资源的路径
3.1.1 Response对象的属性
| Response对象的属性 | 说明 | 备注 |
|---|---|---|
| r.status_code | HTTP请求的返回状态,200表示连接成功,404表示失败 | |
| r.text | HTTP响应内容的字符串形式,即url对应的页面内容 | |
| r.encoding | 从HTTP header 中猜测的向相应内容的编码格式 | |
| r.apparent_encoding | 从内容中分析的响应内容编码格式 | |
| r.content | HTTP响应内容的二进制形式 |
3.1.2 异常
| Requests库的异常 | 说明 | 备注 |
|---|---|---|
| r.raise_for_status | 如果不是200,产生异常requests.HTTPError | |
| requests.ConnectionError | 网络连接错误,如DNS查询失败、防火墙拒绝连接 | |
| requests.HTTPError | HTTP错误异常 | |
| requests.URLRequired | URL缺失异常 | |
| requests.TooManyRedirects | 超过最大重定向次数,产生重定向异常 | |
| requests.ConnetcTimeout | 连接远程服务器超时异常 | 仅指连接到服务器的时间 |
| requests.Timeout | 请求URL超时,产生超时异常 | 客户端产生连接到收到返回内容的时间 |
3.1.3常用框架流程
3.1.4常用框架
# -*- coding: utf-8 -*-
"""
Created on Thu May 18 20:33:42 2017
@author: suning 1107914055@qq.com
"""
import requests
def getHTMLText(url):
try:
r = requests.get(url)
r.raise_for_status()
r.encoding = r.apparent_encoding
#return r.text
return r.headers
except:
return '产生异常'
if __name__ == "__main__":
url = "http://www.baidu.com"
print(getHTMLText(url))
3.2 requests.head方法
r = requests.head("http://httpbin.org/get")
print(r.headers)
{'Connection': 'keep-alive', 'Server': 'meinheld/0.6.1', 'Date': 'Fri, 19 May 2017 05:38:50 GMT', 'Content-Type': 'application/json', 'Access-Control-Allow-Origin': '*', 'Access-Control-Allow-Credentials': 'true', 'X-Powered-By': 'Flask', 'X-Processed-Time': '0.000622987747192', 'Content-Length': '267', 'Via': '1.1 vegur'}
3.3requests.post方法
post 一个字典
payload = {'key1':'value1','key2':'value2'}
r = requests.post('http://httpbin.org/post',data = payload)
print(r.text)
{
"args": {},
"data": "",
"files": {},
"form": {
"key1": "value1",
"key2": "value2"
},
"headers": {
"Accept": "*/*",
"Accept-Encoding": "gzip, deflate",
"Connection": "close",
"Content-Length": "23",
"Content-Type": "application/x-www-form-urlencoded",
"Host": "httpbin.org",
"User-Agent": "python-requests/2.12.4"
},
"json": null,
"origin": "223.167.127.235",
"url": "http://httpbin.org/post"
}
post 一个字符串
n [22]: r = requests.post('http://httpbin.org/post',data = 'abxcc')
print(r.text)
{
"args": {},
"data": "abxcc",
"files": {},
"form": {},
"headers": {
"Accept": "*/*",
"Accept-Encoding": "gzip, deflate",
"Connection": "close",
"Content-Length": "5",
"Host": "httpbin.org",
"User-Agent": "python-requests/2.12.4"
},
"json": null,
"origin": "223.167.127.235",
"url": "http://httpbin.org/post"
}
put一个字典(覆盖原有数据)
r = requests.put('http://httpbin.org/put',data = payload)
print(r.text)
{
"args": {},
"data": "",
"files": {},
"form": {
"key1": "value1",
"key2": "value2"
},
"headers": {
"Accept": "*/*",
"Accept-Encoding": "gzip, deflate",
"Connection": "close",
"Content-Length": "23",
"Content-Type": "application/x-www-form-urlencoded",
"Host": "httpbin.org",
"User-Agent": "python-requests/2.12.4"
},
"json": null,
"origin": "223.167.127.235",
"url": "http://httpbin.org/put"
}
主要方法
requests.request(method,url,**kwargs)
method:请求方式,对应get/put/post等7种
url:拟获取页面的URL链接
**kwargs:控制访问的参数,共13个
| Tables | Are | Cool |
|---|---|---|
访问控制参数1:
params:字典或字节序列,作为参数增加到url中
>>> kv = {'key1':'value1','key2':'value2'}
>>> r = requests.request('GET','http://python123.io/ws',params=kv)
>>> print r.url
'http://python123.io/ws?key1=value1&key2=value2'
访问控制参数2:
data:字典、字节序列或文件对象,作为Request的内容
#data是字典
>>> payload = {'key1':'value1','key2':'value2'}
>>> r = requests.post('http://httpbin.org/post',data = payload)
>>> print(r.url)
http://httpbin.org/post
>>> print(r.text)
{
"args": {},
"data": "",
"files": {},
"form": {
"key1": "value1",
"key2": "value2"
},
"headers": {
"Accept": "*/*",
"Accept-Encoding": "gzip, deflate",
"Connection": "close",
"Content-Length": "23",
"Content-Type": "application/x-www-form-urlencoded",
"Host": "httpbin.org",
"User-Agent": "python-requests/2.12.4"
},
"json": null,
"origin": "223.167.127.235",
"url": "http://httpbin.org/post"
}
#data是字符串
>>> r = requests.post('http://httpbin.org/post',data = 'text')
>>> print(r.url)
'http://httpbin.org/post'
>>> print(r.text)
{
"args": {},
"data": "text",
"files": {},
"form": {},
"headers": {
"Accept": "*/*",
"Accept-Encoding": "gzip, deflate",
"Connection": "close",
"Content-Length": "4",
"Host": "httpbin.org",
"User-Agent": "python-requests/2.12.4"
},
"json": null,
"origin": "223.167.127.235",
"url": "http://httpbin.org/post"
}
#data是文件对象
>>> file = open('D:/file1.txt',mode='r')
>>> r = requests.post('http://httpbin.org/post',data = file)
>>> r.url
'http://httpbin.org/post'
>>> print(r.text)
{
"args": {},
"data": "iiiiiiiiiiii:",
"files": {},
"form": {},
"headers": {
"Accept": "*/*",
"Accept-Encoding": "gzip, deflate",
"Connection": "close",
"Content-Length": "13",
"Host": "httpbin.org",
"User-Agent": "python-requests/2.12.4"
},
"json": null,
"origin": "223.167.127.235",
"url": "http://httpbin.org/post"
}
访问控制参数3:
json:JSON格式的数据,作为Request的内容
>>> kv = {'key1': 'value1', 'key2': 'value2'}
>>> r = requests.request('POST','http://python123.io/ws',json=kv)
>>> print(r.url)
'http://python123.io/ws'
>>> print(r.text)
Not Found
访问控制参数4:
headers:字典,HTTP定制头
hd = {'user-agent','Chrome/10'}
r = requests.request('POST','http://python123.io/ws',headers=hd)
访问控制参数5:
cookies:字典或CookerJar,request中的cookie
访问控制参数6:
auth:元组,支持HTTP认证功能
访问控制参数7:
files:字典类型,传输文件
fs = {'file':open('D:/data.xls','rb')}
r = requests.request('POST','http://python123.io/ws',files=fs)
访问控制参数8:
timeout:设定超时时间,单位为秒
r = requests.request('GET','http://www.baidu.com',timeout=10)
访问控制参数9:
proxiex:字典类型,设定访问代理服务器,可以增加登录认证
>>> pxs = {'http':'http://user:pass@10.10.10.1:1234' 'https':'https://10.10.10.1:4321'}
>>> r =requests.request('GET','http://www.baiud.com',proxies=pxs)
访问控制参数10:
allow_redirects:True/False,默认为True,默认为True,重定向开关
访问控制参数11:
stream:True/False,默认为True,获取内容立即下载开关
访问控制参数12:
verify:True/False,默认为True,认证SSL证书开关
访问控制参数13:
cert:本地SSL证书路径
应用
百度的关键词接口:
https:www.baidu.com/s?wd=keyword
kv = {'wd':'keyword'}
r = requests.get('http://www.baidu.com/s',params=kv)
360的关键词接口
http://www.so.com/s?q=keyword
kv = {'q':'keyword'}
r = requests.get('http://www.so.com/s',params=kv)
图片爬取
#!/usr/local/python-2.7.13/bin/virtualenv python
# -*- coding: utf-8 -*-
"""
Created on Thu May 18 20:33:42 2017
@author: suning 1107914055@qq.com
"""
import requests
import os
url = "http://www.qzone.la/DownFile/354878/1448965"
root = "/tmp/pic/"
path = root + url.split('/')[-1] + ".jpg"
try:
if not os.path.exists(root):
os.mkdir(root)
if not os.path.exists(path):
r = requests.get(url)
with open(path,'wb') as f:
f.write(r.content)
f.close()
print('文件以保存')
else:
print('文件已存在')
except:
print('爬取失败')
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