session_test.py

"""
http://docs.python-requests.org/en/master/user/advanced/#session-objects
When your app makes a connection to a server using a Session,
it keeps that connection around in a connection pool.
When your app wants to connect to the same server again,
it will reuse a connection from the pool rather than establishing a new one.
"""

import requests

s = requests.Session()
s.auth = ('user', 'pass')  # session-level的dict会被session persist
s.headers.update({'x-test': 'true'})  # session-level的dict会被session persist

# both 'x-test' and 'x-test2' are sent
resp = s.get('https://httpbin.org/headers', headers={'x-test2': 'true'})
resp2 = s.get('https://httpbin.org/headers')
s.headers['x-test'] = None
resp3 = s.get('https://httpbin.org/headers')
s.auth = None
resp4 = s.get('https://httpbin.org/headers')

print(resp.request.headers)
print(resp2.request.headers)
print(resp3.request.headers)
print(resp4.request.headers)

s = requests.Session()
resp5 = s.get('https://httpbin.org/headers', auth=('yangkai', 'pass'))  # method-level的dict不会被session persist
print(resp5.request.headers)
resp6 = s.get('https://httpbin.org/headers')
print(resp6.request.headers)

print()
with requests.Session() as s:
    jar = requests.cookies.RequestsCookieJar()
    jar.set('tasty_cookie', 'yum')
    s.cookies = jar
    resp7 = s.get("http://httpbin.org/cookies")
    s.cookies.clear()
    resp8 = s.get("http://httpbin.org/cookies")
    print(resp7.request.headers)
    print(resp8.request.headers)
    print(resp7.text)
    print(resp8.text)

输出结果为

{'User-Agent': 'python-requests/2.21.0', 'Accept-Encoding': 'gzip, deflate', 'Accept': '*/*', 'Connection': 'keep-alive', 'x-test': 'true', 'x-test2': 'true', 'Authorization': 'Basic dXNlcjpwYXNz'}
{'User-Agent': 'python-requests/2.21.0', 'Accept-Encoding': 'gzip, deflate', 'Accept': '*/*', 'Connection': 'keep-alive', 'x-test': 'true', 'Authorization': 'Basic dXNlcjpwYXNz'}
{'User-Agent': 'python-requests/2.21.0', 'Accept-Encoding': 'gzip, deflate', 'Accept': '*/*', 'Connection': 'keep-alive', 'Authorization': 'Basic dXNlcjpwYXNz'}
{'User-Agent': 'python-requests/2.21.0', 'Accept-Encoding': 'gzip, deflate', 'Accept': '*/*', 'Connection': 'keep-alive'}
{'User-Agent': 'python-requests/2.21.0', 'Accept-Encoding': 'gzip, deflate', 'Accept': '*/*', 'Connection': 'keep-alive', 'Authorization': 'Basic eWFuZ2thaTpwYXNz'}
{'User-Agent': 'python-requests/2.21.0', 'Accept-Encoding': 'gzip, deflate', 'Accept': '*/*', 'Connection': 'keep-alive'}

{'User-Agent': 'python-requests/2.21.0', 'Accept-Encoding': 'gzip, deflate', 'Accept': '*/*', 'Connection': 'keep-alive', 'Cookie': 'tasty_cookie=yum'}
{'User-Agent': 'python-requests/2.21.0', 'Accept-Encoding': 'gzip, deflate', 'Accept': '*/*', 'Connection': 'keep-alive'}
{
  "cookies": {
    "tasty_cookie": "yum"
  }
}

{
  "cookies": {}
}