问题
I'm building a website + backend with the FLask Framework in which I use Flask-OAuthlib to authenticate with google. After authentication, the backend needs to regularly scan the user his Gmail. So currently users can authenticate my app and I store the access_token and the refresh_token. The access_token expires after one hour, so within that one hour I can get the userinfo like so:
google = oauthManager.remote_app(
'google',
consumer_key='xxxxxxxxx.apps.googleusercontent.com',
consumer_secret='xxxxxxxxx',
request_token_params={
'scope': ['https://www.googleapis.com/auth/userinfo.email', 'https://www.googleapis.com/auth/gmail.readonly'],
'access_type': 'offline'
},
base_url='https://www.googleapis.com/oauth2/v1/',
request_token_url=None,
access_token_method='POST',
access_token_url='https://accounts.google.com/o/oauth2/token',
authorize_url='https://accounts.google.com/o/oauth2/auth'
)
token = (the_stored_access_token, '')
userinfoObj = google.get('userinfo', token=token).data
userinfoObj['id'] # Prints out my google id
Once the hour is over, I need to use the refresh_token (which I've got stored in my database) to request a new access_token. I tried replacing the_stored_access_token with the_stored_refresh_token, but this simply gives me an Invalid Credentials-error.
In this github issue I read the following:
regardless of how you obtained the access token / refresh token (whether through an authorization code grant or resource owner password credentials), you exchange them the same way, by passing the refresh token as refresh_token and grant_type set to 'refresh_token'.
From this I understood I had to create a remote app like so:
google = oauthManager.remote_app(
'google',
# also the consumer_key, secret, request_token_params, etc..
grant_type='refresh_token',
refresh_token=u'1/xK_ZIeFn9quwvk4t5VRtE2oYe5yxkRDbP9BQ99NcJT0'
)
But this leads to a TypeError: __init__() got an unexpected keyword argument 'refresh_token'. So from here I'm kinda lost.
Does anybody know how I can use the refresh_token to get a new access_token? All tips are welcome!
回答1:
This is how I get a new access_token for google:
from urllib2 import Request, urlopen, URLError
from webapp2_extras import json
import mimetools
BOUNDARY = mimetools.choose_boundary()
def refresh_token()
url = google_config['access_token_url']
headers = [
("grant_type", "refresh_token"),
("client_id", <client_id>),
("client_secret", <client_secret>),
("refresh_token", <refresh_token>),
]
files = []
edata = EncodeMultiPart(headers, files, file_type='text/plain')
headers = {}
request = Request(url, headers=headers)
request.add_data(edata)
request.add_header('Content-Length', str(len(edata)))
request.add_header('Content-Type', 'multipart/form-data;boundary=%s' % BOUNDARY)
try:
response = urlopen(request).read()
response = json.decode(response)
except URLError, e:
...
EncodeMultipart function is taken from here: https://developers.google.com/cloud-print/docs/pythonCode
Be sure to use the same BOUNDARY
回答2:
Looking at the source code for OAuthRemoteApp. The constructor does not take a keyword argument called refresh_token. It does however take an argument called access_token_params which is an optional dictionary of parameters to forward to the access token url.
Since the url is the same, but the grant type is different. I imagine a call like this should work:
google = oauthManager.remote_app(
'google',
# also the consumer_key, secret, request_token_params, etc..
grant_type='refresh_token',
access_token_params = {
refresh_token=u'1/xK_ZIeFn9quwvk4t5VRtE2oYe5yxkRDbP9BQ99NcJT0'
}
)
回答3:
flask-oauthlib.contrib contains an parameter named auto_refresh_url / refresh_token_url in the remote_app which does exactely what you wanted to wanted to do. An example how to use it looks like this:
app= oauth.remote_app(
[...]
refresh_token_url='https://www.douban.com/service/auth2/token',
authorization_url='https://www.douban.com/service/auth2/auth',
[...]
)
However I did not manage to get it running this way. Nevertheless this is possible without the contrib package. My solution was to catch 401 API calls and redirect to a refresh page if a refresh_token is available. My code for the refresh endpoint looks as follows:
@app.route('/refresh/')
def refresh():
data = {}
data['grant_type'] = 'refresh_token'
data['refresh_token'] = session['refresh_token'][0]
data['client_id'] = CLIENT_ID
data['client_secret'] = CLIENT_SECRET
# make custom POST request to get the new token pair
resp = remote.post(remote.access_token_url, data=data)
# checks the response status and parses the new tokens
# if refresh failed will redirect to login
parse_authorized_response(resp)
return redirect('/')
def parse_authorized_response(resp):
if resp is None:
return 'Access denied: reason=%s error=%s' % (
request.args['error_reason'],
request.args['error_description']
)
if isinstance(resp, dict):
session['access_token'] = (resp['access_token'], '')
session['refresh_token'] = (resp['refresh_token'], '')
elif isinstance(resp, OAuthResponse):
print(resp.status)
if resp.status != 200:
session['access_token'] = None
session['refresh_token'] = None
return redirect(url_for('login'))
else:
session['access_token'] = (resp.data['access_token'], '')
session['refresh_token'] = (resp.data['refresh_token'], '')
else:
raise Exception()
return redirect('/')
Hope this will help. The code can be enhanced of course and there surely is a more elegant way than catching 401ers but it's a start ;)
One other thing: Do not store the tokens in the Flask Session Cookie. Rather use Server Side Sessions from "Flask Session" which I did in my code!
来源：https://stackoverflow.com/questions/27146469/how-to-use-a-refresh-token-to-get-a-new-access-token-using-flask-oauthlib