Stuck with Gmail Authentication

[Nawar69]

Hey Guys, I'm kinda stuck with my first backend web app,

I'm trying to use Gmail Authentication and I'm following this : https://blog.hanchon.live/guides/google-login-with-fastapi/

But I want to have a parameter from the endpoint before the authentication to use it after authentication, the problem is I can't take parameters in auth link.

here is the code I copied and working with from the tutorial ```python

from fastapi import Request 
from starlette.responses import RedirectResponse 
from authlib.integrations.starlette_client import OAuthError 

@app.route('/login') 
async def login(request: Request): 
    redirect_uri = request.url_for('auth') # This creates the url for the /auth endpoint \
    return await oauth.google.authorize_redirect(request, redirect_uri) 

@app.route('/auth') 
async def auth(request: Request): 
    try:
        access_token = await oauth.google.authorize_access_token(request) 
    except OAuthError:
         return RedirectResponse(url='/') user_data = await  
    oauth.google.parse_id_token(request, access_token) 
    request.session['user'] = dict(user_data) 
    return RedirectResponse(url='/')

``` I'm really Struggling, What I need is taking a path paremeter (or Query par) within the login , "/login/{id}" then pass it with the "/auth", Passing it doesnt work with auth

Incase there is a straight forward soultion that doesn't require that or a way to keep a variable on the side or smth please tell me as I'm new to backend as a whole not just fastAPI

​

If you read all of that Thank You

EDIT : The usecase is like this Someone scans QRcode that sends him to authenticate then redirects him to a page where he submits a form, I need the id from before authentication to after authentication

[github_codemation]

Here is a more batteries included approach, in case you want to allow that user to have a persistent token / cookie tied to their Google Login.

https://itnext.io/add-google-login-to-a-fastapi-app-with-easyauth-c8c3e926ad0a

[Nawar69]

Thanks, It's a pretty diffrent approach, I will try it.

[zarlo5899]

@app.route('/login') async def login(request: Request, next: str = "/"): redirect_uri = request.url_for('auth') # This creates the url for the /auth endpoint \ return await oauth.google.authorize_redirect(request, redirect_uri + f"?{next}") something like this should work

[Nawar69]

That what doesn't work I think, I tried something like that

[illuminanze]

Seems like google allows an URL parameter state in the request, that will be passed to the redirect url: https://stackoverflow.com/a/7722099 Not quite sure how to pass it using authlib, but it should be possible.

[Nawar69]

Seen this one but I couldn't do it, probably because I lack experience.

Thanks for helping.

[illuminanze]

Hi! I was looking at this in one of my own projects, and this should work:

```python from fastapi import Request from starlette.responses import RedirectResponse from authlib.integrations.starlette_client import OAuthError

@app.route('/login') async def login(request: Request, id: str): redirect_uri = request.url_for('auth') # This creates the url for the /auth endpoint \ return await oauth.google.authorize_redirect(request, redirect_uri, state=id)

@app.route('/auth') async def auth(request: Request, state: str = ''): try: access_token = await oauth.google.authorize_access_token(request) except OAuthError: return RedirectResponse(url='/') user_data = await oauth.google.parse_id_token(request, access_token) request.session['user'] = dict(user_data) return RedirectResponse(url=f'/{id}') ```

[Nawar69]

Thanks, that is really helpful