前言
以下关于Requests的内容讲解,强烈推荐深入了解的查看官方文档。
中文版:Requests、 http://cn.python-requests.org/zh_CN/latest/
Requests
- Requests是用python语言基于urllib编写的,采用的是Apache2 Licensed开源协议的HTTP库。
- 默认安装好python之后,是没有安装requests模块的,需要单独通过pip安装。
- requests是python实现的最简单易用的HTTP库,建议爬虫使用requests库。
Get请求
以下代码使用了对 get请求的参数、请求的header、请求的超时设置、请求的返回参数进行示例。可自行根据需要进行删减。
import requests
# 第一种设置请求参数的方法:get请求的参数写成字典的形式,作为get请求的params参数传入
data = {
"name":"luozheng",
"age":22
}
# 第二种设置请求参数的方法 response = requests.get("http://httpbin.org/get?name=luozhengfan&age=23")
# 添加header
headers = {
"User-Agent":"Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.121 Safari/537.36"
}
response = requests.get("http://httpbin.org/get", params=data, headers=headers, timeout=5)
print(type(response))
print(response.status_code)
print(type(response.text))
print(response.text)
print(response.cookies)
# 二进制,用于解析视频、图片等
print(response.content)
print(response.content.decode("utf-8"))
print(response.history)
"""
<class 'requests.models.Response'>
200
<class 'str'>
{
"args": {
"age": "22",
"name": "luozheng"
},
......
}
<RequestsCookieJar[]>
b'{\n "args": {\n "age": "22", \n "name": "luozheng"\n }, ......}'
{
"args": {
"age": "22",
"name": "luozheng"
},
......
}
[]
"""
Post请求
Post请求的与上面的Get请求类似,唯一不同的是对data参数进行设置时,只能使用字典对参数进行设置,并将参数作为data赋值传入。
import requests
# 设置post请求的参数
data = {
"name":"luozheng",
"age":22
}
# 添加header
headers = {
"User-Agent":"Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.121 Safari/537.36"
}
response = requests.post("http://httpbin.org/post", data=data, headers=headers, timeout=5)
print(response.text)
# 二进制,用于解析视频、图片等
print(response.content)
print(response.content.decode("utf-8"))
其他用法
- 解析json
requests里面集成的json其实就是执行了json.loads()方法,两者的结果是一样的。
import requests
import json
response = requests.get("http://httpbin.org/get?name=luozhengfan&age=23")
print(type(response.text))
print(response.json())
print(json.loads(response.text))
print(type(response.json()))
"""
<class 'str'>
{'args': {'age': '23', 'name': 'luozhengfan'}, ...}
{'args': {'age': '23', 'name': 'luozhengfan'}, ...}
<class 'dict'>
"""
-
获取二进制数据
获取响应的文本直接 response.text 。而上面提到了response.content,这样获取的数据是二进制数据,同样的这个方法也可以用于下载图片以及视频资源 -
状态码判断
Requests附带了一个内置的状态码查询对象,示例如下:
import requests
response= requests.get("http://www.baidu.com")
if response.status_code == requests.codes.ok:
print("访问成功")
"""
100: ('continue',),
101: ('switching_protocols',),
102: ('processing',),
103: ('checkpoint',),
122: ('uri_too_long', 'request_uri_too_long'),
200: ('ok', 'okay', 'all_ok', 'all_okay', 'all_good', '\o/', '✓'),
201: ('created',),
202: ('accepted',),
203: ('non_authoritative_info', 'non_authoritative_information'),
204: ('no_content',),
205: ('reset_content', 'reset'),
206: ('partial_content', 'partial'),
207: ('multi_status', 'multiple_status', 'multi_stati', 'multiple_stati'),
208: ('already_reported',),
226: ('im_used',),
Redirection.
300: ('multiple_choices',),
301: ('moved_permanently', 'moved', '\o-'),
302: ('found',),
303: ('see_other', 'other'),
304: ('not_modified',),
305: ('use_proxy',),
306: ('switch_proxy',),
307: ('temporary_redirect', 'temporary_moved', 'temporary'),
308: ('permanent_redirect',
'resume_incomplete', 'resume',), # These 2 to be removed in 3.0
Client Error.
400: ('bad_request', 'bad'),
401: ('unauthorized',),
402: ('payment_required', 'payment'),
403: ('forbidden',),
404: ('not_found', '-o-'),
405: ('method_not_allowed', 'not_allowed'),
406: ('not_acceptable',),
407: ('proxy_authentication_required', 'proxy_auth', 'proxy_authentication'),
408: ('request_timeout', 'timeout'),
409: ('conflict',),
410: ('gone',),
411: ('length_required',),
412: ('precondition_failed', 'precondition'),
413: ('request_entity_too_large',),
414: ('request_uri_too_large',),
415: ('unsupported_media_type', 'unsupported_media', 'media_type'),
416: ('requested_range_not_satisfiable', 'requested_range', 'range_not_satisfiable'),
417: ('expectation_failed',),
418: ('im_a_teapot', 'teapot', 'i_am_a_teapot'),
421: ('misdirected_request',),
422: ('unprocessable_entity', 'unprocessable'),
423: ('locked',),
424: ('failed_dependency', 'dependency'),
425: ('unordered_collection', 'unordered'),
426: ('upgrade_required', 'upgrade'),
428: ('precondition_required', 'precondition'),
429: ('too_many_requests', 'too_many'),
431: ('header_fields_too_large', 'fields_too_large'),
444: ('no_response', 'none'),
449: ('retry_with', 'retry'),
450: ('blocked_by_windows_parental_controls', 'parental_controls'),
451: ('unavailable_for_legal_reasons', 'legal_reasons'),
499: ('client_closed_request',),
Server Error.
500: ('internal_server_error', 'server_error', '/o\', '✗'),
501: ('not_implemented',),
502: ('bad_gateway',),
503: ('service_unavailable', 'unavailable'),
504: ('gateway_timeout',),
505: ('http_version_not_supported', 'http_version'),
506: ('variant_also_negotiates',),
507: ('insufficient_storage',),
509: ('bandwidth_limit_exceeded', 'bandwidth'),
510: ('not_extended',),
511: ('network_authentication_required', 'network_auth', 'network_authentication'),
"""
Requests高级用法
主要包括了文件上传,证书验证,代理设置,认证设置。
- 文件上传
实现方法和其他参数类似,也是构造一个字典然后通过files参数传递
import requests
files = {"files":open("wechat.png","rb")}
response = requests.post("http://httpbin.org/post", files=files)
print(response.text)
"""
{
"args": {},
"data": "",
"files": {
"files": "data:application/octet-stream;base64,iVBORw0KGg......YII="
},
"form": {},
"headers": {
"Accept": "*/*",
"Accept-Encoding": "gzip, deflate",
"Content-Length": "38735",
"Content-Type": "multipart/form-data; boundary=a18f2223063180433033132aee71a297",
"Host": "httpbin.org",
"User-Agent": "python-requests/2.22.0"
},
"json": null,
"origin": "117.183.8.254, 117.183.8.254",
"url": "https://httpbin.org/post"
}
"""
- 证书验证
对于https访问的证书验证,不设置可能会报错 ssl.SSLError 错误。
import requests
# 消除警告InsecureRequestWarning
requests.packages.urllib3.disable_warnings()
response = requests.get("https://www.12306.cn",verify=False)
print(response.status_code)
- 代理设置
代理设置通常为第一种情况,其他两种情况请看注释。
import requests
proxies= {
"http":"http://127.0.0.1:9999",
"https":"http://127.0.0.1:8888"
}
response = requests.get("https://www.baidu.com",proxies=proxies)
print(response.text)
"""
如果代理需要设置账户名和密码,只需要将字典更改为如下:
proxies = {
"http":"http://user:password@127.0.0.1:9999"
}
如果你的代理是通过sokces这种方式则需要pip install "requests[socks]"
proxies= {
"http":"socks5://127.0.0.1:9999",
"https":"sockes5://127.0.0.1:8888"
}
"""
- 认证设置
如果碰到需要认证的网站可以通过requests.auth模块实现。
import requests
from requests.auth import HTTPBasicAuth
response = requests.get("http://120.27.34.24:9001/",auth=HTTPBasicAuth("user","123"))
print(response.status_code)
"""
import requests
response = requests.get("http://120.27.34.24:9001/",auth=("user","123"))
print(response.status_code)
"""
requests cookie与会话维持session cookie
- requests cookie
主要是对requests请求的cookie进行获取和设置,请看以下代码。
## 获取cookie
import requests
response = requests.get("http://www.baidu.com")
print(response.cookies)
for key, value in response.cookies.items():
print(key+"="+value)
"""
<RequestsCookieJar[<Cookie BDORZ=27315 for .baidu.com/>]>
BDORZ=27315
"""
##设置cookie
import requests
jar = requests.cookies.RequestsCookieJar()
jar.set('tasty_cookie', 'yum', domain='httpbin.org', path='/cookies')
jar.set('gross_cookie', 'blech', domain='httpbin.org', path='/cookies')
url = 'http://httpbin.org/cookies'
r = requests.get(url, cookies=jar)
print(r.text)
"""
{
"cookies": {
"gross_cookie": "blech",
"tasty_cookie": "yum"
}
}
"""
- 会话维持session cookie
由于不同的requests请求之间是独立的,因此维持回话状态,只能创建一个session对象,请求都通过这个对象访问。
以下介绍三种设置会话session的cookie的方法,第一种简单,第二种可以设置cookie的作用域,第三种每个请求都要设置。
import requests
s = requests.Session()
s.get("http://httpbin.org/cookies/set/number/123456")
response = s.get("http://httpbin.org/cookies")
print(response.text)
- add_dict_to_cookiejar对会话进行cookie设置
import requests
s = requests.session()
mycookie = {"tasty_cookie":"yum","gross_cookie":"blech"}
s.cookies = requests.utils.add_dict_to_cookiejar(s.cookies, mycookie)
r = s.get("http://httpbin.org/cookies")
print(r.text)
"""
{
"cookies": {
"gross_cookie": "blech",
"tasty_cookie": "yum"
}
}
"""
- session.cookies.set 对会话进行cookie设置
import requests
s = requests.session()
s.cookies.set('tasty_cookie', 'yum', domain='httpbin.org', path='/cookies')
s.cookies.set('gross_cookie', 'blech', domain='httpbin.org', path='/cookies')
r = s.get("http://httpbin.org/cookies")
print(r.text)
- 第三种…
这种每个requests请求都要加上,有点繁琐。
import requests
s = requests.session()
mycookie = {"tasty_cookie":"yum","gross_cookie":"blech"}
r = s.get("http://127.0.0.1:80",cookies = mycookie)
print(r.text)
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文章地址:Python爬虫(二)— 深入了解Requests模块