python-requests保持函数之间的会话

Question

i use requests to login to a website and keep session active

def test():

s = requests.session()

but how can use the variable "s" in another function and keep it alive to perform other post on the current session ? Because the variable is private to the function. I'm tempted to make it global but i read everywhere that it's not a good practice. I'm new to Python and i want to code clean.

Answer 1

You'll need to either return it from the function or pass it in to the function in the first place.

def do_something_remote():
    s = requests.session()
    blah = s.get('http://www.example.com/')
    return s

def other_function():
    s = do_something_remote()
    something_else_with_same_session = s.get('http://www.example.com/')

A better pattern is for a more 'top-level' function to be responsible for creating the session and then having sub functions use that session.

def master():
    s = requests.session()

    # we're now going to use the session in 3 different function calls
    login_to_site(s)
    page1 = scrape_page(s, 'page1')
    page2 = scrape_page(s, 'page2')

    # once this function ends we either need to pass the session up to the
    # calling function or it will be gone forever

def login_to_site(s):
    s.post('http://www.example.com/login')

def scrape_page(s, name):
    page = s.get('http://www.example.com/secret_page/{}'.format(name))
    return page

EDIT In python a function can actually have multiple return values:

def doing_something():
   s = requests.session()
   # something here.....
   # notice we're returning 2 things
   return some_result, s

def calling_it():
   # there's also a syntax for 'unpacking' the result of calling the function
   some_result, s = doing_something()