python中requests库使用方法详解

Posted 2020-11-07 peter200-ok

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一、什么是Requests

Requests 是?ython语?编写，基于urllib，采?Apache2 Licensed开源协议的 HTTP 库。它? urllib 更加?便，
可以节约我们?量的?作，完全满?HTTP测试需求。

?句话——Python实现的简单易?的HTTP库

二、安装Requests库

进入命令行win+R执行

命令：pip install requests

项目导入：import requests

三、各种请求方式

直接上代码，不明白可以查看我的urllib的基本使用方法

1 import requests
2 requests.post(‘http://httpbin.org/post‘)
3 requests.put(‘http://httpbin.org/put‘)
4 requests.delete(‘http://httpbin.org/delete‘)
5 requests.head(‘http://httpbin.org/get‘)
6 requests.options(‘http://httpbin.org/get‘)

这么多请求方式，都有什么含义，所以问下度娘：

GET：请求指定的页面信息，并返回实体主体。
HEAD：只请求页面的首部。
POST：请求服务器接受所指定的文档作为对所标识的URI的新的从属实体。
PUT：从客户端向服务器传送的数据取代指定的文档的内容。
DELETE：请求服务器删除指定的页面。
get 和 post比较常见 GET请求将提交的数据放置在HTTP请求协议头中
POST提交的数据则放在实体数据中
（1）、基本的GET请求

 1 import requests
 2 
 3 response = requests.get(‘http://httpbin.org/get‘)
 4 print(response.text)
 5 返回值：
 6 
 7 {
 8   "args": {}, 
 9   "headers": {
10     "Accept": "*/*", 
11     "Accept-Encoding": "gzip, deflate", 
12     "Connection": "close", 
13     "Host": "httpbin.org", 
14     "User-Agent": "python-requests/2.18.4"
15   }, 
16   "origin": "183.64.61.29", 
17   "url": "http://httpbin.org/get"
18 }
19 （2）、带参数的GET请求
20 
21 将name和age传进去
22 
23 import requests
24 response = requests.get("http://httpbin.org/get?name=germey&age=22")
25 print(response.text)
26 {
27   "args": {
28     "age": "22", 
29     "name": "germey"
30   }, 
31   "headers": {
32     "Accept": "*/*", 
33     "Accept-Encoding": "gzip, deflate", 
34     "Connection": "close", 
35     "Host": "httpbin.org", 
36     "User-Agent": "python-requests/2.18.4"
37   }, 
38   "origin": "183.64.61.29", 
39   "url": "http://httpbin.org/get?name=germey&age=22"
40 }
41 或者使用params的方法：
42 
43 import requests
44 
45 data = {
46  ‘name‘: ‘germey‘,
47  ‘age‘: 22
48 }
49 response = requests.get("http://httpbin.org/get", params=data)
50 print(response.text)
51 返回值一样
52 
53 （3）、解析json
54 
55 将返回值已json的形式展示：
56 
57 import requests
58 import json
59 
60 response = requests.get("http://httpbin.org/get")
61 print(type(response.text))
62 print(response.json())
63 print(json.loads(response.text))
64 print(type(response.json()))
65 返回值：
66 
67 <class ‘str‘>
68 {‘args‘: {}, ‘headers‘: {‘Accept‘: ‘*/*‘, ‘Accept-Encoding‘: ‘gzip, deflate‘, ‘Connection‘: ‘close‘, ‘Host‘: ‘httpbin.org‘, ‘User-Agent‘: ‘python-requests/2.18.4‘}, ‘origin‘: ‘183.64.61.29‘, ‘url‘: ‘http://httpbin.org/get‘}
69 {‘args‘: {}, ‘headers‘: {‘Accept‘: ‘*/*‘, ‘Accept-Encoding‘: ‘gzip, deflate‘, ‘Connection‘: ‘close‘, ‘Host‘: ‘httpbin.org‘, ‘User-Agent‘: ‘python-requests/2.18.4‘}, ‘origin‘: ‘183.64.61.29‘, ‘url‘: ‘http://httpbin.org/get‘}
70 <class ‘dict‘>
71 （4）、获取二进制数据
72 
73 记住返回值.content就ok了
74 
75 import requests
76 
77 response = requests.get("https://github.com/favicon.ico")
78 print(type(response.text), type(response.content))
79 print(response.text)
80 print(response.content)

返回值为二进制不必再进行展示，

（5）、添加headers

有些网站访问时必须带有浏览器等信息，如果不传入headers就会报错，如下

 1 import requests
 2 
 3 response = requests.get("https://www.zhihu.com/explore")
 4 print(response.text)
 5 返回值：
 6 
 7 <html><body><h1>500 Server Error</h1>
 8 An internal server error occured.
 9 </body></html>
10 当传入headers时：
11 
12 import requests
13 
14 headers = {
15  ‘User-Agent‘: ‘Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36‘
16 }
17 response = requests.get("https://www.zhihu.com/explore", headers=headers)
18 print(response.text)

成功返回网页源代码不做展示

（6）、基本POST请求

不明白见我博文urllib的使用方法

 1 import requests
 2 
 3 data = {‘name‘: ‘germey‘, ‘age‘: ‘22‘}
 4 response = requests.post("http://httpbin.org/post", data=data)
 5 print(response.text)
 6 返回：
 7 
 8 {
 9   "args": {}, 
10   "data": "", 
11   "files": {}, 
12   "form": {
13     "age": "22", 
14     "name": "germey"
15   }, 
16   "headers": {
17     "Accept": "*/*", 
18     "Accept-Encoding": "gzip, deflate", 
19     "Connection": "close", 
20     "Content-Length": "18", 
21     "Content-Type": "application/x-www-form-urlencoded", 
22     "Host": "httpbin.org", 
23     "User-Agent": "python-requests/2.18.4"
24   }, 
25   "json": null, 
26   "origin": "183.64.61.29", 
27   "url": "http://httpbin.org/post"
28 }

三、响应

response属性

 1 import requests
 2 
 3 response = requests.get(‘http://www.jianshu.com‘)
 4 print(type(response.status_code), response.status_code)
 5 print(type(response.headers), response.headers)
 6 print(type(response.cookies), response.cookies)
 7 print(type(response.url), response.url)
 8 print(type(response.history), response.history)
 9 return：
10 
11 <class ‘int‘> 200
12 <class ‘requests.structures.CaseInsensitiveDict‘> {‘Date‘: ‘Thu, 01 Feb 2018 20:47:08 GMT‘, ‘Server‘: ‘Tengine‘, ‘Content-Type‘: ‘text/html; charset=utf-8‘, ‘Transfer-Encoding‘: ‘chunked‘, ‘X-Frame-Options‘: ‘DENY‘, ‘X-XSS-Protection‘: ‘1; mode=block‘, ‘X-Content-Type-Options‘: ‘nosniff‘, ‘ETag‘: ‘W/"9f70e869e7cce214b6e9d90f4ceaa53d"‘, ‘Cache-Control‘: ‘max-age=0, private, must-revalidate‘, ‘Set-Cookie‘: ‘locale=zh-CN; path=/‘, ‘X-Request-Id‘: ‘366f4cba-8414-4841-bfe2-792aeb8cf302‘, ‘X-Runtime‘: ‘0.008350‘, ‘Content-Encoding‘: ‘gzip‘, ‘X-Via‘: ‘1.1 gjf22:8 (Cdn Cache Server V2.0), 1.1 PSzqstdx2ps251:10 (Cdn Cache Server V2.0)‘, ‘Connection‘: ‘keep-alive‘}
13 <class ‘requests.cookies.RequestsCookieJar‘> <RequestsCookieJar[<Cookie locale=zh-CN for www.jianshu.com/>]>
14 <class ‘str‘> https://www.jianshu.com/
15 <class ‘list‘> [<Response [301]>]
16 状态码判断：常见的网页状态码：
17 
18 100: (‘continue‘,),
19 101: (‘switching_protocols‘,),
20 102: (‘processing‘,),
21 103: (‘checkpoint‘,),
22 122: (‘uri_too_long‘, ‘request_uri_too_long‘),
23 200: (‘ok‘, ‘okay‘, ‘all_ok‘, ‘all_okay‘, ‘all_good‘, ‘\\o/‘, ‘?‘),
24 201: (‘created‘,),
25 202: (‘accepted‘,),
26 203: (‘non_authoritative_info‘, ‘non_authoritative_information‘),
27 204: (‘no_content‘,),
28 205: (‘reset_content‘, ‘reset‘),
29 206: (‘partial_content‘, ‘partial‘),
30 207: (‘multi_status‘, ‘multiple_status‘, ‘multi_stati‘, ‘multiple_stati‘),
31 208: (‘already_reported‘,),
32 226: (‘im_used‘,),
33 
34 # Redirection.
35 300: (‘multiple_choices‘,),
36 301: (‘moved_permanently‘, ‘moved‘, ‘\\o-‘),
37 302: (‘found‘,),
38 303: (‘see_other‘, ‘other‘),
39 304: (‘not_modified‘,),
40 305: (‘use_proxy‘,),
41 306: (‘switch_proxy‘,),
42 307: (‘temporary_redirect‘, ‘temporary_moved‘, ‘temporary‘),
43 308: (‘permanent_redirect‘,
44  ‘resume_incomplete‘, ‘resume‘,), # These 2 to be removed in 3.0
45 
46 # Client Error.
47 400: (‘bad_request‘, ‘bad‘),
48 401: (‘unauthorized‘,),
49 402: (‘payment_required‘, ‘payment‘),
50 403: (‘forbidden‘,),
51 404: (‘not_found‘, ‘-o-‘),
52 405: (‘method_not_allowed‘, ‘not_allowed‘),
53 406: (‘not_acceptable‘,),
54 407: (‘proxy_authentication_required‘, ‘proxy_auth‘, ‘proxy_authentication‘),
55 408: (‘request_timeout‘, ‘timeout‘),
56 409: (‘conflict‘,),
57 410: (‘gone‘,),
58 411: (‘length_required‘,),
59 412: (‘precondition_failed‘, ‘precondition‘),
60 413: (‘request_entity_too_large‘,),
61 414: (‘request_uri_too_large‘,),
62 415: (‘unsupported_media_type‘, ‘unsupported_media‘, ‘media_type‘),
63 416: (‘requested_range_not_satisfiable‘, ‘requested_range‘, ‘range_not_satisfiable‘),
64 417: (‘expectation_failed‘,),
65 418: (‘im_a_teapot‘, ‘teapot‘, ‘i_am_a_teapot‘),
66 421: (‘misdirected_request‘,),
67 422: (‘unprocessable_entity‘, ‘unprocessable‘),
68 423: (‘locked‘,),
69 424: (‘failed_dependency‘, ‘dependency‘),
70 425: (‘unordered_collection‘, ‘unordered‘),
71 426: (‘upgrade_required‘, ‘upgrade‘),
72 428: (‘precondition_required‘, ‘precondition‘),
73 429: (‘too_many_requests‘, ‘too_many‘),
74 431: (‘header_fields_too_large‘, ‘fields_too_large‘),
75 444: (‘no_response‘, ‘none‘),
76 449: (‘retry_with‘, ‘retry‘),
77 450: (‘blocked_by_windows_parental_controls‘, ‘parental_controls‘),
78 451: (‘unavailable_for_legal_reasons‘, ‘legal_reasons‘),
79 499: (‘client_closed_request‘,),
80 
81 # Server Error.
82 500: (‘internal_server_error‘, ‘server_error‘, ‘/o\\‘, ‘?‘),
83 501: (‘not_implemented‘,),
84 502: (‘bad_gateway‘,),
85 503: (‘service_unavailable‘, ‘unavailable‘),
86 504: (‘gateway_timeout‘,),
87 505: (‘http_version_not_supported‘, ‘http_version‘),
88 506: (‘variant_also_negotiates‘,),
89 507: (‘insufficient_storage‘,),
90 509: (‘bandwidth_limit_exceeded‘, ‘bandwidth‘),
91 510: (‘not_extended‘,),
92 511: (‘network_authentication_required‘, ‘network_auth‘, ‘network_authentication‘),

四、高级操作

（1）、文件上传

使用 Requests 模块，上传文件也是如此简单的，文件的类型会自动进行处理：

实例：

import requests

files = {‘file‘: open(‘cookie.txt‘, ‘rb‘)}
response = requests.post("http://httpbin.org/post", files=files)
print(response.text)
这是通过测试网站做的一个测试，返回值如下：

{
"args": {},
"data": "",
"files": {
"file": "#LWP-Cookies-2.0\r\nSet-Cookie3: BAIDUID=\"D2B4E137DE67E271D87F03A8A15DC459:FG=1\"; path=\"/\"; domain=\".baidu.com\"; path_spec; domain_dot; expires=\"2086-02-13 11:15:12Z\"; version=0\r\nSet-Cookie3: BIDUPSID=D2B4E137DE67E271D87F03A8A15DC459; path=\"/\"; domain=\".baidu.com\"; path_spec; domain_dot; expires=\"2086-02-13 11:15:12Z\"; version=0\r\nSet-Cookie3: H_PS_PSSID=25641_1465_21087_17001_22159; path=\"/\"; domain=\".baidu.com\"; path_spec; domain_dot; discard; version=0\r\nSet-Cookie3: PSTM=1516953672; path=\"/\"; domain=\".baidu.com\"; path_spec; domain_dot; expires=\"2086-02-13 11:15:12Z\"; version=0\r\nSet-Cookie3: BDSVRTM=0; path=\"/\"; domain=\"www.baidu.com\"; path_spec; discard; version=0\r\nSet-Cookie3: BD_HOME=0; path=\"/\"; domain=\"www.baidu.com\"; path_spec; discard; version=0\r\n"
},
"form": {},
"headers": {
"Accept": "*/*",
"Accept-Encoding": "gzip, deflate",
"Connection": "close",
"Content-Length": "909",
"Content-Type": "multipart/form-data; boundary=84835f570cfa44da8f4a062b097cad49",
"Host": "httpbin.org",
"User-Agent": "python-requests/2.18.4"
},
"json": null,
"origin": "183.64.61.29",
"url": "http://httpbin.org/post"
}

（2）、获取cookie

当需要cookie时，直接调用response.cookie

response为请求后的返回值)

import requests

response = requests.get("https://www.baidu.com")
print(response.cookies)
for key, value in response.cookies.items():
print(key + ‘=‘ + value)

输出结果：

<RequestsCookieJar[<Cookie BDORZ=27315 for .baidu.com/>]>
BDORZ=27315
（3）、会话维持、模拟登陆

如果某个响应中包含一些Cookie，你可以快速访问它们：

import requests

r = requests.get(‘http://www.google.com.hk/‘)
print(r.cookies[‘NID‘])
print(tuple(r.cookies))

要想发送你的cookies到服务器，可以使用 cookies 参数：

import requests

url = ‘http://httpbin.org/cookies‘
cookies = {‘testCookies_1‘: ‘Hello_Python3‘, ‘testCookies_2‘: ‘Hello_Requests‘}
# 在Cookie Version 0中规定空格、方括号、圆括号、等于号、逗号、双引号、斜杠、问号、@，冒号，分号等
特殊符号都不能作为Cookie的内容。
r = requests.get(url, cookies=cookies)
print(r.json())
（4）、证书验证

因为12306有一个错误证书，我们那它的网站做测试会出现下面的情况，证书不是官方证书，浏览器会识别出
一个错误

import requests

response = requests.get(‘https://www.12306.cn‘)
print(response.status_code)
返回值：

怎么正常进入这样的网站了，代码如下：

import requests
from requests.packages import urllib3
urllib3.disable_warnings()
response = requests.get(‘https://www.12306.cn‘, verify=False)
print(response.status_code)
将verify设置位False即可，返回的状态码为200

urllib3.disable_warnings()这条命令主要用于消除警告信息

（5）、代理设置

在进行爬虫爬取时，有时候爬虫会被服务器给屏蔽掉，这时采用的方法主要有降低访问时间，通过代理ip访问，
如下：

import requests

proxies = {
"http": "http://127.0.0.1:9743",
"https": "https://127.0.0.1:9743",
}

response = requests.get("https://www.taobao.com", proxies=proxies)
print(response.status_code)
ip可以从网上抓取，或者某宝购买

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:[email protected]: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"
}

（6）、超时设置

访问有些网站时可能会超时，这时设置好timeout就可以解决这个问题

import requests
from requests.exceptions import ReadTimeout
try:
response = requests.get("http://httpbin.org/get", timeout = 0.5)
print(response.status_code)
except ReadTimeout:
print(‘Timeout‘)

正常访问，状态吗返回200

（7）、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)
当然这里还有一种方式

import requests

response = requests.get("http://120.27.34.24:9001/",auth=("user","123"))
print(response.status_code)
（8）、异常处理

遇到网络问题（如：DNS查询失败、拒绝连接等）时，Requests会抛出一个ConnectionError 异常。

遇到罕见的无效HTTP响应时，Requests则会抛出一个 HTTPError 异常。

若请求超时，则抛出一个 Timeout 异常。

若请求超过了设定的最大重定向次数，则会抛出一个 TooManyRedirects 异常。

所有Requests显式抛出的异常都继承自 requests.exceptions.RequestException 。

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