三. Requests库的基本使用
Requests库的基本使用
Requests库的基本使用
Requests 是用Python语 编写，基于urllib，采用Apache2 Licensed 开源协议的 HTTP 库。
它比urllib更加方便，可以节约我们大量的事件，完全满足HTTP 测试需求。
简而言之——Rquest库是Python实现的简单的HTTP库。
实例引入
import requests
response = requests.get('https://www.baidu.com/')
print(type(response))
print(response.status_code)
print(type(response.text))
print(response.text)
print(response.cookies)各种网络请求
import requests
requests.post('http://httpbin.org/post')
requests.put('http://httpbin.org/put')
requests.delete('http://httpbin.org/delete')
requests.head('http://httpbin.org/get')
requests.options('http://httpbin.org/get')基本get请求
import requests
response = requests.get('http://httpbin.org/get')
print(response.text)显示结果如下：
{
“args”: {},
“headers”: {
“Accept”: “/“,
“Accept-Encoding”: “gzip, deflate”,
“Connection”: “close”,
“Host”: “httpbin.org”,
“User-Agent”: “python-requests/2.14.2”
},
“origin”: “49.80.114.107”,
“url”: “http://httpbin.org/get”
}
带参数的get请求
import requests
response = requests.get("http://httpbin.org/get?name=germey&age=22")
print(response.text)显示结果如下：
{
“args”: {
“age”: “22”,
“name”: “germey”
},
“headers”: {
“Accept”: “/“,
“Accept-Encoding”: “gzip, deflate”,
“Connection”: “close”,
“Host”: “httpbin.org”,
“User-Agent”: “python-requests/2.14.2”
},
“origin”: “49.80.114.107”,
“url”: “http://httpbin.org/get?name=germey&age=22”
}
更简便的方法是构造一个字典。传入参数，代码如下
import requests
data = {
'name': 'germey',
'age': 22
}
response = requests.get("http://httpbin.org/get", params=data)
print(response.text)结果和之前的一样。效果也一样的。
解析json
对于有ajax请求的网页一般解析json的方法。
import requests
import json
response = requests.get("http://httpbin.org/get")
print(type(response.text))
print(response.json())
print(json.loads(response.text))
print(type(response.json()))获取二进制数据
用response.content方法来获取。
import requests
response = requests.get("https://github.com/favicon.ico")
print(type(response.text), type(response.content))
print(response.text)
print(response.content)再写进文件。
import requests
response = requests.get("https://github.com/favicon.ico")
with open('favicon.ico', 'wb') as f:
f.write(response.content)
f.close()添加headers
如果不添加headers，一些网页会把你的访问禁掉，或者服务器没有响应。
例如下面我们不添加头信息访问知乎网的首页：
import requests
response = requests.get("https://www.zhihu.com/explore")
print(response.text)结果为:
<html><body><h1>500 Server Errorh1>
An internal server error occured.
body>html>可以看出并不能正确访问知乎网的主页。
但是加入头信息后，便能正确访问。
import requests
headers = {
'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'
}
response = requests.get("https://www.zhihu.com/explore", headers=headers)
print(response.text)便能够正确访问知乎网主页。
基本POST请求
data参数加进request。data类型可以为字典，会自动帮你转化成URL中的参数，因为自己写带参数的URL很繁琐。
import requests
data = {'name': 'germey', 'age': '22'}
response = requests.post("http://httpbin.org/post", data=data)
print(response.text)输出结果为
{
"args": {},
"data": "",
"files": {},
"form": {
"age": "22",
"name": "germey"
},
"headers": {
"Accept": "*/*",
"Accept-Encoding": "gzip, deflate",
"Connection": "close",
"Content-Length": "18",
"Content-Type": "application/x-www-form-urlencoded",
"Host": "httpbin.org",
"User-Agent": "python-requests/2.14.2"
},
"json": null,
"origin": "49.80.114.106",
"url": "http://httpbin.org/post"
}添加headers
和加入data方式一样。只要传入headers就行了。
import requests
data = {'name': 'germey', 'age': '22'}
headers = {
'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'
}
response = requests.post("http://httpbin.org/post", data=data, headers=headers)
print(response.json())综上，post和get使用起来并没有太大的差异。
响应
response的属性
import requests
response = requests.get('http://www.jianshu.com')
print(type(response.status_code), response.status_code)
print(type(response.headers), response.headers)
print(type(response.cookies), response.cookies)
print(type(response.url), response.url)
print(type(response.history), response.history)状态码的判断
请求成功返回的状态码为200:
import requests
response = requests.get('http://www.jianshu.com')
exit() if not response.status_code == 200 else print('Request Successfully')404 not found:
import requests
response = requests.get('http://www.jianshu.com/hello.html')
exit() if not response.status_code == requests.codes.not_found else print('404 Not Found')下面列出所有的状态码：
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'),高级操作
文件上传
基本使用方法：
import requests
files = {'file': open('favicon.ico', 'rb')}
response = requests.post("http://httpbin.org/post", files=files)
print(response.text)怎样获取cookies
import requests
response = requests.get("https://www.baidu.com")
print(response.cookies)
for key, value in response.cookies.items():
print(key + '=' + value)回话维持
用来做模拟登陆
import requests
requests.get('http://httpbin.org/cookies/set/number/123456789')
response = requests.get('http://httpbin.org/cookies')
print(response.text)通过session对象发起请求。
import requests
s = requests.Session()
s.get('http://httpbin.org/cookies/set/number/123456789')
response = s.get('http://httpbin.org/cookies')
print(response.text)证书验证
检测证书的合法性，如果证书不合法会中断程序：
import requests
response = requests.get('https://www.12306.cn')
print(response.status_code)结果会报SSL错误
---------------------------------------------------------------------------
SSLError Traceback (most recent call last)解决办法很简单：
import requests
from requests.packages import urllib3
urllib3.disable_warnings()
response = requests.get('https://www.12306.cn', verify=False)
print(response.status_code)只要get的时候把vertify改为false就好了。默认true。
代理设置
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)超时设置
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')认证设置
有些页面你登陆了才能看。解决方法如下：
import requests
r = requests.get('http://120.27.34.24:9001', auth=('user', '123'))
print(r.status_code)异常处理
import requests
from requests.exceptions import ReadTimeout, ConnectionError, RequestException
try:
response = requests.get("http://httpbin.org/get", timeout = 0.5)
print(response.status_code)
except ReadTimeout:
print('Timeout')
except ConnectionError:
print('Connection error')
except RequestException:
print('Error')