[包計劃] requests

requests

Python 中一個易用的網絡請求庫

來源

• 官方文檔
• 中文文檔
• GitHub

使用

發送請求

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')

傳遞 URL 參數

# 字典裏值爲 None 的鍵都不會被添加到 URL 的查詢字符串裏
payload = {'key1': 'value1', 'key2': 'value2'}
r = requests.get("http://httpbin.org/get", params=payload)

響應內容

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

二進制響應內容

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

JSON 響應內容

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

原始響應內容

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

定製請求頭

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]>

複雜的 POST 請求

import requests
import json

# 表單
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一個多部分編碼(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)

響應狀態碼

import requests

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

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


bad_r = requests.get('http://httpbin.org/status/404')
print(bad_r.status_code)  # 404
bad_r.raise_for_status()  # 錯誤請求 拋出異常

響應頭

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

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

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

重定向與請求歷史

import requests
# 追蹤重定向
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

超時

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

錯誤與異常

• 遇到網絡問題時，Requests 會拋出一個 ConnectionError 異常。
• 若是 HTTP 請求返回了不成功的狀態碼， Response.raise_for_status() 會拋出一個 HTTPError 異常。
• 若請求超時，則拋出一個 Timeout 異常。
• 若請求超過了設定的最大重定向次數，則會拋出一個 TooManyRedirects 異常。
• 全部 Requests 顯式拋出的異常都繼承自 requests.exceptions.RequestException 。