[包计划] requests

requests

Python 中一个易用的网络请求库

来源

• 官方文档
• 中文文档
• GitHub

使用

发送请求

r = requests.get('https://api.github.com/events')
r = requests.post('http://httpbin.org/post', data = {'key':'value'})
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')

传递 URL 参数

# 字典里值为 None 的键都不会被添加到 URL 的查询字符串里
payload = {'key1': 'value1', 'key2': 'value2'}
r = requests.get("http://httpbin.org/get", params=payload)

响应内容

import requests
r = requests.get('https://api.github.com/events')
print(r.text)  # [{"id":"8462576403"}]
print(r.encoding)  # utf-8

二进制响应内容

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

JSON 响应内容

import requests
r = requests.get('https://api.github.com/events')
print(r.json())  # [{'id': '8462617752'}]

原始响应内容

import requests
r = requests.get('https://api.github.com/events', stream=True)
print(r.raw)  # <urllib3.response.HTTPResponse object at 0x10c813550>

定制请求头

import requests
url = 'https://api.github.com/some/endpoint'
headers = {'user-agent': 'my-app/0.0.1'}
r = requests.get(url, headers=headers)
print(r)  # <Response [404]>

复杂的 POST 请求

import requests
import json

# 表单
payload = {'key1': 'value1', 'key2': 'value2'}
r = requests.post("http://httpbin.org/post", data=payload)
print(r.text)

# JSON
url = 'https://api.github.com/some/endpoint'
payload = {'some': 'data'}
r = requests.post(url, data=json.dumps(payload))
print(r.text)

# JSON   2.4.2 版的新加功能
url = 'https://api.github.com/some/endpoint'
payload = {'some': 'data'}
r = requests.post(url, json=payload)
print(r.text)

POST一个多部分编码(Multipart-Encoded)的文件

import requests

url = 'http://httpbin.org/post'
files = {'file': open('test.txt', 'rb')}

r = requests.post(url, files=files)
print(r.text)

响应状态码

import requests

r = requests.get('http://httpbin.org/get')
print(r.status_code)  # 200

print(requests.codes.ok)  # 常量，代表 200
print(requests.codes.not_found)  # 常量，代表 404


bad_r = requests.get('http://httpbin.org/status/404')
print(bad_r.status_code)  # 404
bad_r.raise_for_status()  # 错误请求 抛出异常

响应头

import requests

r = requests.get('http://httpbin.org/get')
print(r.headers)
print(r.headers['Content-Type'])  # application/json
print(r.headers['content-type'])  # application/json

Cookie

import requests

#  获取 cookie
url = 'http://httpbin.org/cookies'
r = requests.get(url)
print(r.cookies)

#  设置 cookie
url = 'http://httpbin.org/cookies'
cookies = dict(cookies_are='working')
r = requests.get(url, cookies=cookies)
print(r.text)

重定向与请求历史

import requests
# 追踪重定向
r = requests.get('http://github.com')
print(r.history)  # [<Response [301]>]

# 禁用重定向
r = requests.get('http://github.com', allow_redirects=False)
print(r.status_code)  # 301

超时

import requests
r = requests.get('http://github.com', timeout=0.001)

错误与异常

• 遇到网络问题时，Requests 会抛出一个 ConnectionError 异常。
• 如果 HTTP 请求返回了不成功的状态码， Response.raise_for_status() 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 。