Python requests库(一)

1.Requests 库介绍

• Requests是一个Python HTTP库，在Apache 2许可证下发布。该项目的目标是使HTTP请求更简单，更人性化。

2.安装方式

• 直接使用pip安装

  pip install requests

• 验证是否安装成功,如果可以正常导入，则说明成功

  Python 3.7.5 (default, Nov 29 2019, 14:32:46)
  [Clang 9.0.0 (clang-900.0.39.2)] on darwin
  Type "help", "copyright", "credits" or "license" for more information.
  >>> import requests
  >>>

  3.简单的例子

• 进入python命令行模式

  ➜  ~ source yiluo/bin/activate
  (yiluo) ➜  ~ python
  Python 3.7.5 (default, Nov 29 2019, 14:32:46)
  [Clang 9.0.0 (clang-900.0.39.2)] on darwin
  Type "help", "copyright", "credits" or "license" for more information.
  >>>

• 请求下简书的首页先

  >>> import requests
  >>> r =requests.get('https://www.jianshu.com/')
  >>> print(r.status_code)
  403
  >>>

  很不幸返回的状态码不是 200

• 加个header再尝试一下

  >>> import requests
  >>> headers = {'User-Agent':'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.108 Safari/537.36'}
  >>> r = requests.get('https://www.jianshu.com', headers = headers)
  >>> print(r.status_code)
  200

  这次请求成功了，上面代码中 r 是 Response对象，可以在这个对象中获取到我们想要的信息, 我们再输出些其他的响应内容看下

  >>> import requests
  >>> headers = {'User-Agent':'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.108 Safari/537.36'}
  >>> r = requests.get('https://www.jianshu.com', headers = headers)
  >>> print(type(r))
  <class 'requests.models.Response'>
  >>> print(type(r.text))
  <class 'str'>
  >>> print(r.cookies)
  <RequestsCookieJar[<Cookie locale=zh-CN for www.jianshu.com/>]>

  如上输出了响应的类型，响应体类型，响应的cookies

• 其他 HTTP 请求类型 PUT，DELETE，HEAD 以及 OPTIONS

  >>> r = requests.put('http://httpbin.org/put', data = {'key':'value'})
  >>> r = requests.delete('http://httpbin.org/delete')
  >>> r = requests.head('http://httpbin.org/get')
  >>> r = requests.options('http://httpbin.org/get')

  4.经常使用的请求

• requests 构建GET请求的方法

  >>> import requests
  >>> r = requests.get('http://httpbin.org/get')
  >>> print(r.text)
  {
    "args": {},
    "headers": {
      "Accept": "*/*",
      "Accept-Encoding": "gzip, deflate",
      "Host": "httpbin.org",
      "User-Agent": "python-requests/2.22.0"
    },
    "origin": "116.25.147.198, 116.25.147.198",
    "url": "https://httpbin.org/get"
  }

• GET请求传递参数

  >>> import requests
  >>> data = {'name':'Tom', 'age':18}
  >>> r = requests.get("http://httpbin.org/get", params=data)
  >>> print(r.text)
  {
    "args": {
      "age": "18",
      "name": "Tom"
    },
    "headers": {
      "Accept": "*/*",
      "Accept-Encoding": "gzip, deflate",
      "Host": "httpbin.org",
      "User-Agent": "python-requests/2.22.0"
    },
    "origin": "116.25.147.198, 116.25.147.198",
    "url": "https://httpbin.org/get?name=Tom&age=18"
  }

• requests 构建POST请求的方法

  >>> import requests
  >>> data = {'name':'Tom', 'age':'18'}
  >>> r = requests.post('http://httpbin.org/post', data = data)
  >>> print(r.text)
  {
    "args": {},
    "data": "",
    "files": {},
    "form": {
      "age": "18",
      "name": "Tom"
    },
    "headers": {
      "Accept": "*/*",
      "Accept-Encoding": "gzip, deflate",
      "Content-Length": "15",
      "Content-Type": "application/x-www-form-urlencoded",
      "Host": "httpbin.org",
      "User-Agent": "python-requests/2.22.0"
    },
    "json": null,
    "origin": "116.25.147.198, 116.25.147.198",
    "url": "https://httpbin.org/post"
  }

  5.具体的一些使用方式

• 传递URL参数
  Requests 允许你使用 params 关键字参数，以一个字符串字典来提供这些参数

  >>> import requests
  >>> payload = {'key1': 'value1', 'key2': 'value2'}
  >>> r = requests.get("http://httpbin.org/get", params=payload)
  >>> print(r.url)
  http://httpbin.org/get?key1=value1&key2=value2

• JSON 响应内容
  Requests 内置的 JSON 解码器，处理 JSON 数据：

  >>> import requests
  >>> r = requests.get('https://api.github.com/events')
  >>> r.json()

• 定制请求头
  为请求添加 HTTP 头部，只要传递一个 dict 给 headers 参数就可以

  >>> import requests
  >>> url = 'https://api.github.com/some/endpoint'
  >>> headers = {'user-agent': 'my-app/0.0.1'}
  >>> r = requests.get(url, headers=headers)

……待续

)

享受每一天，Just Enjoy !

---