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python: how to redirect from desktop app to url, wait user to accept the authorization and get authorization code

I'm working on an app using the Spotify API but I'm a bit new to all of this. I'm trying to get the Authorization Code with Proof Key for Code Exchange (PKCE) (https://developer.spotify.com/documentation/general/guides/authorization-guide/#authorization-code-flow-with-proof-key-for-code-exchange-pkce)
My problem is how do I redirect the user to the query where he has to ACCEPT the authorization and make my app to wait until the user clicks on ACCEPT. When he does this, the user will be redirected and that new URL (as the docs said) will contain the authorization code that I need to then exchange it for an authorization token.
This is my function so far to get that authorization code:
def get_auth_code(self):
code_challenge = self.get_code_challenge_PKCE()
scopes_needed = "user-read-email%20user-read-private%20playlist-read-collaborative%20playlist-modify-public%20playlist-read-private%20playlist-modify-private%20user-library-modify%20user-library-read"
endpoint = "https://accounts.spotify.com/authorize"
query = f"{endpoint}?client_id={self.client_ID}&response_type=code&redirect_uri={self.redirect_uri}&scope={scopes_needed}&code_challenge_method=S256&code_challenge={code_challenge}"
webbrowser.open(query)

Set up a web server.
To programmatially extract the access tokens you need a web server to handle the redirection after the user logs in on Spotify (which you redirected them to). Now this server can be the user pasting the URI to an input field on a terminal, but obviously this isn't ideal for user experience. It leaves room for lots of mistakes.
I've authored a Spotify Web API client, whose internals might be useful for you to examine. For example, you can use Flask to construct the server. The main principle is using one endpoint (i.e. /login) to redirect (code 307 worked for me browsers won't remember it) the user to a callback (i.e. /callback) which recieves the code parameter with which you can request an access token.
OAuth2 can be a bit of a pain to implement locally, I know. In my library I also made a similar function that you are constructing using webbrowser, but it does have the manual copy-pasting quirk. To use functions you can define yourself for brevity, the gist of it is:
verifier = secrets.token_urlsafe(32) # for PKCE, not in my library yet
url = user_authorisation_url(scope, state, verifier)
# Communicate with the user
print('Opening browser for Spotify login...')
webbrowser.open(url)
redirected = input('Please paste redirect URL: ').strip()
code = parse_code_from_url(redirected)
state_back = parse_state_from_url(redirected)
assert state == state_back # For that added security juice
token = request_user_token(code, verifier)

Implementing Google Directory API users watch with Python

I'm having some trouble understanding and implementing the Google Directory API's users watch function and push notification system (https://developers.google.com/admin-sdk/reports/v1/guides/push#creating-notification-channels) in my Python GAE app. What I'm trying to achieve is that any user (admin) who uses my app would be able to watch user changes within his own domain.
I've verified the domain I want to use for notifications and implemented the watch request as follows:
directoryauthdecorator = OAuth2Decorator(
approval_prompt='force',
client_id='my_client_id',
client_secret='my_client_secret',
callback_path='/oauth2callback',
scope=['https://www.googleapis.com/auth/admin.directory.user'])
class PushNotifications(webapp.RequestHandler):
#directoryauthdecorator.oauth_required
def get(self):
auth_http = directoryauthdecorator.http()
service = build("admin", "directory_v1", http=auth_http)
uu_id=str(uuid.uuid4())
param={}
param['customer']='my_customer'
param['event']='add'
param['body']={'type':'web_hook','id':uu_id,'address':'https://my-domain.com/pushNotifications'}
watchUsers = service.users().watch(**param).execute()
application = webapp.WSGIApplication(
[
('/pushNotifications',PushNotifications),
(directoryauthdecorator.callback_path, directoryauthdecorator.callback_handler())],
debug=True)
Now, the receiving part is what I don't understand. When I add a user on my domain and check the app's request logs I see some activity, but there's no usable data. How should I approach this part?
Any help would be appreciated. Thanks.

The problem
It seems like there's been some confusion in implementing the handler. Your handler actually sets up the notifications channel by sending a POST request to the Reports API endpoint. As the docs say:
To set up a notification channel for messages about changes to a particular resource, send a POST request to the watch method for the resource.
source
You should only need to send this request one time to set up the channel, and the "address" parameter should be the URL on your app that will receive the notifications.
Also, it's not clear what is happening with the following code:
param={}
param['customer']='my_customer'
param['event']='add'
Are you just breaking the code in order to post it here? Or is it actually written that way in the file? You should actually preserve, as much as possible, the code that your app is running so that we can reason about it.
The solution
It seems from the docs you linked - in the "Receiving Notifications" section, that you should have code inside the "address" specified to receive notifications that will inspect the POST request body and headers on the notification push request, and then do something with that data (like store it in BigQuery or send an email to the admin, etc.)

Managed to figure it out. In the App Engine logs I noticed that each time I make a change, which is being 'watched', on my domain I get a POST request from Google's API, but with a 302 code. I discovered that this was due to the fact I had login: required configured in my app.yaml for the script, which was handling the requests and the POST request was being redirected to the login page, instead of the processing script.

How to detect url callback request

I have a locally-run app that makes API calls to a website (tumblr.com). This involves setting some OAuth credentials; one step along the way requires extracting a key from a callback url that the server directs the browser to. So what I currently have the user do is:
Open an authorization link in a browser, which prompts them to authorize the OAuth application on the website
Click through the authorization page on the website (“Yes, I allow xxxxx app to access certain info associated with my account”)
Clicking Authorize app makes a request to the localhost which includes a parameter in the url. Meaning that tumblr will redirect the browser to the page http://localhost/?oauth_token={TOKEN}&oauth_verifier={VERIFIER}#_=_. I assume that causes a request to be made to the local machine when it does that.
The user is expected to isolate the key parameter in the url from the browser’s navigation bar, and paste it in the application.
So is there any way I can bypass steps 3 and 4 and simply have the app pick up the callback request instead of expecting the user to copy and paste it from the browser? I’m afraid I don’t know much about how to handle network requests in python.
To be clear, what I need to do is get the {VERIFIER} string.

okay first thing first, for http requests, a good python module is requests
http://docs.python-requests.org/en/master/
Then, your app gives a callback address to tumblr so that tumblr can tell to your app client info, or login error.
Now, your point 3 isn't clear.
"Clicking authorize app makes a request to localhost"
Actually clicking "authorize app" for the user makes a request to tumblr saying he accepts.
Then tumblr makes a request to your callback url passing the infos.
The callback url should probably be your server address, there you must have a script listening for tumblr, which will give you your special parameter to call their api...
In addition :
So when the users click "authorize app" there is a request to tumblr, which redirects the user to the callback url (adding oauth token and verifier).
Now, obviously, you can't ask for every user to have an http server running on their computer.
So you must set the callback url to your server.
So if you set it to "myserver.com/tumblr" for instance, the user will get redirected to your webpage, and you'll get on your server, and for that user session, the oauths token and verifier.
and...
Assuming your app is client only I'd say there are two options.
Either have your users enter manually their API keys.
Or either embed a webserver into your app.
In the case of the embedded webserver, I'd suggest flask for its simplicity.
Simply have your webserver listen on a given port and set the callback url to that server:port.
This way you'll get the client tokens directly.

401 Unauthorized making REST Call to Azure API App using Bearer token

I created 2 applications in my Azure directory, 1 for my API Server and one for my API client. I am using the Python ADAL Library and can successfully obtain a token using the following code:
tenant_id = "abc123-abc123-abc123"
context = adal.AuthenticationContext('https://login.microsoftonline.com/' + tenant_id)
token = context.acquire_token_with_username_password(
'https://myapiserver.azurewebsites.net/',
'myuser',
'mypassword',
'my_apiclient_client_id'
)
I then try to send a request to my API app using the following method but keep getting 'unauthorized':
at = token['accessToken']
id_token = "Bearer {0}".format(at)
response = requests.get('https://myapiserver.azurewebsites.net/', headers={"Authorization": id_token})
I am able to successfully login using myuser/mypass from the loginurl. I have also given the client app access to the server app in Azure AD.

Although the question was posted a long time ago, I'll try to provide an answer. I stumbled across the question because we had the exact same problem here. We could successfully obtain a token with the adal library but then we were not able to access the resource I obtained the token for.
To make things worse, we sat up a simple console app in .Net, used the exact same parameters, and it was working. We could also copy the token obtained through the .Net app and use it in our Python request and it worked (this one is kind of obvious, but made us confident that the problem was not related to how I assemble the request).
The source of the problem was in the end in the oauth2_client of the adal python package. When I compared the actual HTTP requests sent by the .Net and the python app, a subtle difference was that the python app sent a POST request explicitly asking for api-version=1.0.
POST https://login.microsoftonline.com/common//oauth2/token?api-version=1.0
Once I changed the following line in oauth2_client.py in the adal library, I could access my resource.
Changed
return urlparse('{}?{}'.format(self._token_endpoint, urlencode(parameters)))
in the method _create_token_url, to
return urlparse(self._token_endpoint)
We are working on a pull request to patch the library in github.

For the current release of Azure Python SDK, it support authentication with a service principal. It does not support authentication using an ADAL library yet. Maybe it will in future releases.
See https://azure-sdk-for-python.readthedocs.io/en/latest/resourcemanagement.html#authentication for details.
See also Azure Active Directory Authentication Libraries for the platforms ADAL is available on.

#Derek,
Could you set your Issue URL on Azure Portal? If I set the wrong Issue URL, I could get the same error with you. It seems that your code is right.
Base on my experience, you need add your application into Azure AD and get a client ID.(I am sure you have done this.) And then you can get the tenant ID and input into Issue URL textbox on Azure portal.
NOTE:
On old portal(manage.windowsazure.com),in the bottom command bar, click View Endpoints, and then copy the Federation Metadata Document URL and download that document or navigate to it in a browser.
Within the root EntityDescriptor element, there should be an entityID attribute of the form https://sts.windows.net/ followed by a GUID specific to your tenant (called a "tenant ID"). Copy this value - it will serve as your Issuer URL. You will configure your application to use this later.
My demo is as following:
import adal
import requests
TenantURL='https://login.microsoftonline.com/*******'
context = adal.AuthenticationContext(TenantURL)
RESOURCE = 'http://wi****.azurewebsites.net'
ClientID='****'
ClientSect='7****'
token_response = context.acquire_token_with_client_credentials(
RESOURCE,
ClientID,
ClientSect
)
access_token = token_response.get('accessToken')
print(access_token)
id_token = "Bearer {0}".format(access_token)
response = requests.get(RESOURCE, headers={"Authorization": id_token})
print(response)
Please try to modified it. Any updates, please let me know.

Flask-Login + Flask-Sockets = Chaos

I have installed Flask-Login and Flask-Sockets. Both of them work fine HOWEVER when I try to get the current user (using g.user), I get an AttributeError: '_AppCtxGlobals' object has no attribute 'user'
#sockets.route('/echo')
def echo_socket(ws):
with app.app_context():
user = current_user #This causes problems, just like basically anything else that uses something that is not provided in this function
while True:
message = ws.receive()
ws.send("lol")
I am still new with Flask, any help would be super appreciated.

The problem is that you are treating your socket functions as if they were regular requests, which they are not.
In a regular (i.e. non-socket) situation the client sends requests to the server. Each request contains a cookie that was set at login time by Flask-Login. This cookie contains the user that is logged in. Flask-Login has a before_request handler that reads this cookie, loads the user and then exposes it through current_user, so that by the time your function runs you have access to this information.
Socket connections are nothing like the above. For a socket connection the client opens a socket to a route and that establishes a permanent connection with the server. The concept of a request does not exist here, it's just two machines sending and receiving data using their own protocol. Because there are no HTTP requests there is also no cookies, no before_request handlers, no application and request contexts pushed and no current_user from Flask-Login. The socket routes really function outside of the Flask application.
If you need to know the user you will need to have the client send credentials through the socket interface, and you will need to authenticate those credentials in your socket route on your own, since Flask-Login cannot work in the socket environment due to the lack of requests, cookies, etc. A significant difference between sockets and regular routes is that the socket connection is permanent, so you only need to authenticate the user when the connection is established.
I hope this helps. Sorry I don't have a quick and easy solution for you.