python requests模块使用
python的网络编程能力十分强大,其中python中的requests库宣言:HTTP for Humans (给人用的 HTTP 库)
在网络编程中,最基本的任务包含:
- 发送请求
- 登录
- 获取数据
- 解析数据
- 反序列化打印内容
目录:
一、安装
pip install requests
二、基本用法
import requests cs_url = 'http://httpbin.org' r = requests.get("%s/%s" % (cs_url, 'get')) r = requests.post("%s/%s" % (cs_url, 'post')) r = requests.put("%s/%s" % (cs_url, 'put')) r = requests.delete("%s/%s" % (cs_url, 'delete')) r = requests.patch("%s/%s" % (cs_url, 'patch')) r = requests.options("%s/%s" % (cs_url, 'get'))
三、URL传参/获取请求的URL/POST表单
#!/usr/bin/env python # -*- coding: utf-8 -*- import requests payload = {'key1': 'value1', 'key2': 'value2'} # URL 传参 r = requests.get("http://httpbin.org/get", params=payload) # 获取请求的 URL print "GET URL:", r.url # POST 发送编码为表单形式的数据,requests 会自动将 Python 字典序列化为实际的表单内容 r = requests.post("http://httpbin.org/post", data=payload) # 获取响应内容,string print "POST Response:\n", r.content if r.headers.get("content-type") == "application/json": # 获取响应内容,dict类型 print "r.json:\n", r.json() print "form:\n", r.json().get("form")
输出结果:
GET URL: http://httpbin.org/get?key2=value2&key1=value1 POST Response: { "args": {}, "data": "", "files": {}, "form": { "key1": "value1", "key2": "value2" }, "headers": { "Accept": "*/*", "Accept-Encoding": "gzip, deflate", "Content-Length": "23", "Content-Type": "application/x-www-form-urlencoded", "Host": "httpbin.org", "User-Agent": "python-requests/2.11.1" }, "json": null, "origin": "124.250.131.130", "url": "http://httpbin.org/post" } r.json: {u'files': {}, u'origin': u'124.250.131.130', u'form': {u'key2': u'value2', u'key1': u'value1'}, u'url': u'http://httpbin.org/post', u'args': {}, u'headers': {u'Content-Length': u'23', u'Accept-Encoding': u'gzip, deflate', u'Accept': u'*/*', u'User-Agent': u'python-requests/2.11.1', u'Host': u'httpbin.org', u'Content-Type': u'application/x-www-form-urlencoded'}, u'json': None, u'data': u''} form: {u'key2': u'value2', u'key1': u'value1'}
四、HTTP状态码/重定向跳转/请求历史
#!/usr/bin/env python # -*- coding: utf-8 -*- import requests url = "http://github.com" # requests 默认自动地处理了 301/302 跳转。在经过跳转的请求中,返回的 URL 和状态码都是跳转之后的信息;唯独在 history 中,用 Python 列表记录了跳转情况 r = requests.get("http://github.com") print "request URL:", url print "*"*60 print "默认情况,response url:", r.url print "默认情况,response status code:", r.status_code print "默认情况,response history:", r.history print "*"*60 # 有时候我们也想单步追踪页面跳转情况。此时,可以给请求加上 allow_redirects = False 参数。 r = requests.get("http://github.com", allow_redirects=False) print "禁止自动跳转后,response Uurl:", r.url print "禁止自动跳转后,response status code:", r.status_code print "禁止自动跳转后,response history:", r.history
五、请求头
#!/usr/bin/env python # -*- coding: utf-8 -*- import requests cs_url = 'http://httpbin.org/get' r = requests.get(cs_url) # 查看请求头 print "定制前:\n", r.request.headers # 定制请求头,HTTP 头部是大小写不敏感的,如下,User-Agent或user-agent均可 header = { # 微信UA 'User-Agent': 'Mozilla/5.0 (Linux; Android 4.1.1; MI 2 Build/JRO03L) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/37.0.0.0 Mobile MQQBrowser/6.8 TBS/036887 Safari/537.36 MicroMessenger/6.3.27.880 NetType/WIFI Language/zh_CN', # 用户cookie 'Cookie': 'gr_user_id=2e25dc22-6d3a-4190-86ce-2f0a04f357f5;PHPSESSID=786dcb5b1233dadc80817ea0e58a5de0', 'Accept-Encoding': 'gzip', } r = requests.get(cs_url, headers=header) # 查看请求头 print "定制后:\n", r.request.headers
输出结果:
定制前: {'Connection': 'keep-alive', 'Accept-Encoding': 'gzip, deflate', 'Accept': '*/*', 'User-Agent': 'python-requests/2.11.1'} 定制后: {'Connection': 'keep-alive', 'Cookie': 'gr_user_id=2e25dc22-6d3a-4190-86ce-2f0a04f357f5;PHPSESSID=786dcb5b1233dadc80817ea0e58a5de0', 'Accept-Encoding': 'gzip', 'Accept': '*/*', 'User-Agent': 'Mozilla/5.0 (Linux; Android 4.1.1; MI 2 Build/JRO03L) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/37.0.0.0 Mobile MQQBrowser/6.8 TBS/036887 Safari/537.36 MicroMessenger/6.3.27.880 NetType/WIFI Language/zh_CN'}
六、响应头
#!/usr/bin/env python # -*- coding: utf-8 -*- import requests cs_url = 'http://httpbin.org/get' r = requests.get(cs_url) print r.headers
输出结果:
{'Content-Length': '240', 'Server': 'nginx', 'Connection': 'keep-alive', 'Access-Control-Allow-Credentials': 'true', 'Date': 'Wed, 07 Dec 2016 06:22:51 GMT', 'Access-Control-Allow-Origin': '*', 'Content-Type': 'application/json'}
七、响应内容
#!/usr/bin/env python # -*- coding: utf-8 -*- import requests cs_url = 'http://httpbin.org/get' r = requests.get(cs_url) if r.status_code == requests.codes.ok: print "以字节形式返回:\n", r.content print " Unicode编码的文本信息返回:\n", r.text
八、反序列JSON数据
#!/usr/bin/env python # -*- coding: utf-8 -*- import requests r = requests.get("http://httpbin.org/get") if r.headers.get("content-type") == "application/json": # 获取响应内容,dict类型 print "r.json:\n", r.json() print "origin:", r.json().get("origin") else: print r.content
九、Cookie
HTTP 协议是无状态的。因此,若不借助其他手段,远程的服务器就无法知道以前和客户端做了哪些通信.Cookie就是「其他手段」之一。
Cookie 一个典型的应用场景,就是用于记录用户在网站上的登录状态。
1.用户登录成功后,服务器下发一个(通常是加密了的)Cookie 文件。
2.客户端(通常是网页浏览器)将收到的 Cookie 文件保存起来。
3.下次客户端与服务器连接时,将 Cookie 文件发送给服务器,由服务器校验其含义,恢复登录状态(从而避免再次登录)
为了演示该实例,提供服务端简单接口实例代码如下:
# 使用cookie演示登录功能接口 def cookie(request): username = request.GET.get("user") password = request.GET.get("pwd") cookie_content = request.COOKIES login_flag = cookie_content.get("is_login") if login_flag=="True" or (username == "qa" and password == "4399"): msg = { "msg": "login success! Welcome~~", "recive_cookie": cookie_content } response = JsonResponse(msg) response.set_cookie("is_login", True) else: msg = { "msg": "username or password error,please try again!", "recive_cookie": cookie_content } response = JsonResponse(msg) response.set_cookie("is_login", False) return response
cookie示例代码如下,cookie既可通过requests的cookies参数传递,也可以在requests的headers参数传递。(同时存在headers和cookies参数时,headers中的cookie会覆盖cookies参数中的cookie)
#!/usr/bin/env python # -*- coding: utf-8 -*- import requests url = "http://10.1.102.75:8000/cookie" r = requests.get(url) print "没有发送cookie时,服务端返回内容为:", r.content print "获取服务端设置的cookie,cookie为:", r.cookies print "*" * 100 cookies = { "is_login": "True" } r = requests.get(url, cookies=cookies) print "发送cookie时,服务端返回内容为:", r.content print "获取服务端设置的cookie,cookie为:", r.cookies print "*" * 100 headers = { 'cookie': 'send_headers=send cookie form client headers' } r = requests.get(url, headers=headers) print "发送cookie时,服务端返回内容为:", r.content print "获取服务端设置的cookie,cookie为:", r.cookies print "*" * 100
输出结果如:
十、会话对象
会话对象让你能够跨请求保持某些参数。它也会在同一个 Session 实例发出的所有请求之间保持 cookie,所以如果你向同一主机发送多个请求,底层的 TCP 连接将会被重用,从而带来显著的性能提升。看本实例之前请先阅读cookie章节
#!/usr/bin/env python # -*- coding: utf-8 -*- import requests login_url = "http://10.1.102.75:8000/cookie?user=qa&pwd=4399" access_url = "http://10.1.102.75:8000/cookie" s = requests.Session() r = s.get(login_url) print "传入正确账号与密码正确登录后,服务端返回内容为:", r.content print "获取服务端设置的cookie,cookie为:", r.cookies print "*" * 100 r = s.get(access_url) print "已登录后,不发送已登录cookie时或登录账号,访问首页时,服务端返回内容为:", r.content print "获取服务端设置的cookie,cookie为:", r.cookies print "*" * 100 cookies = { "other_cookie": "test send order cookie" } r = s.get(access_url, cookies=cookies) print "已登录后,添加发送非登录cookie,访问首页时服务端返回内容为:", r.content print "获取服务端设置的cookie,cookie为:", r.cookies print "*" * 100
输出结果如下:
十一、超时设置
为防止服务器不能及时响应,大部分发至外部服务器的请求都应该带着 timeout 参数。如果没有 timeout,你的代码可能会挂起若干分钟甚至更长时间。
>>> r = requests.get('https://github.com', timeout=5) >>> r = requests.get('https://github.com', timeout=None) >>>
十二、SSL证书验证
Requests 可以为 HTTPS 请求验证 SSL 证书,就像 web 浏览器一样。要想检查某个主机的 SSL 证书,你可以使用 verify 参数:
>>> requests.get('https://github.com', verify=True) <Response [200]>
默认情况下, verify 是设置为 True 的,如果SSL认证失败,可以尝试将verify验证关闭,verify=False
更多高级使用,请查看 http://docs.python-requests.org/zh_CN/latest/user/advanced.html
1 #!/usr/bin/env python 2 # -*- coding: utf-8 -*- 3 4 """ 5 微信端抽奖活动 6 多线程抽奖,测试前提:去掉一个用户只能参与一次的限制 7 """ 8 import requests 9 from time import ctime 10 import threading 11 12 13 def draw_lottery(): 14 lottery_url = "http://10.1.102.75:8000/activity/gsdzzlottery/lottery" 15 headers = { 16 # 微信UA 17 'user-agent': 'Mozilla/5.0 (Linux; Android 4.1.1; MI 2 Build/JRO03L) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/37.0.0.0 Mobile MQQBrowser/6.8 TBS/036887 Safari/537.36 MicroMessenger/6.3.27.880 NetType/WIFI Language/zh_CN', 18 # 用户cookie 19 'cookie': 'gr_user_id=2e25dc22-6d3a-4190-86ce-2f0a04f357f5; Hm_lvt_0d8e9cf3502496036a00d10b24863c6d=1478072857,1480158524; PHPSESSID=786dcb5b1233dadc80817ea0e58a5de0' 20 } 21 try: 22 conn = requests.get(lottery_url, headers=headers, verify=False) 23 print conn.text 24 except Exception, e: 25 print e 26 27 28 if __name__ == '__main__': 29 print 'start:', ctime() 30 for j in range(2): 31 threads = 300 32 threads_list = [] 33 for i in range(threads): 34 t = threading.Thread(target=draw_lottery, args=()) 35 threads_list.append(t) 36 for i in range(threads): 37 threads_list[i].start() 38 # keep thread 39 for i in range(threads): 40 threads_list[i].join() 41 42 print 'end:', ctime()
#!/usr/bin/env python # -*- coding: utf-8 -*- """ 使用装饰器,并发请求 """ import requests from time import ctime import threading def thread_request(count, loop): """并发请求装饰器,count: 线程数 ; loop: 循环次数 """ def outer(main_func): def inner(): # print "before %s" % main_func for j in range(loop): threads_list = [] for i in range(count): t = threading.Thread(target=main_func, args=()) threads_list.append(t) for th in threads_list: th.start() # keep thread for th in threads_list: th.join() # print "after %s" % main_func return inner return outer @thread_request(count=2, loop=2) def get_result(): url = "http://a.demo.4399th.com/eventapi/base/get_result" data = {"hd_id": 1} headers = { # 微信UA # 'user-agent': 'Mozilla/5.0 (Linux; Android 4.1.1; MI 2 Build/JRO03L) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/37.0.0.0 Mobile MQQBrowser/6.8 TBS/036887 Safari/537.36 MicroMessenger/6.3.27.880 NetType/WIFI Language/zh_CN', # 用户cookie 'cookie': 'a_demo_4399th_com=60a78048563a4b58e5d27d45390be36c' } try: conn = requests.post(url, data=data, headers=headers, verify=False) print conn.text except Exception, e: print e @thread_request(count=2, loop=1) def login(): print "do login" if __name__ == '__main__': print 'start:', ctime() get_result() print 'end:', ctime()
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