Dynamic Token Algorithm

You can specify which algorithm you would like to use to sign the JWT by using the algorithm parameter in create_access_token() or create_refresh_token(). Also you need to specify which algorithms you would like to permit when validating in protected endpoint by settings authjwt_decode_algorithms which take a sequence. If the JWT doesn't have algorithm in authjwt_decode_algorithms the token will be rejected.

from fastapi import FastAPI, HTTPException, Depends, Request
from fastapi.responses import JSONResponse
from fastapi_jwt_auth import AuthJWT
from fastapi_jwt_auth.exceptions import AuthJWTException
from pydantic import BaseModel

app = FastAPI()

class User(BaseModel):
    username: str
    password: str

class Settings(BaseModel):
    authjwt_secret_key: str = "secret"
    # Configure algorithms which is permit
    authjwt_decode_algorithms: set = {"HS384","HS512"}

@AuthJWT.load_config
def get_config():
    return Settings()

@app.exception_handler(AuthJWTException)
def authjwt_exception_handler(request: Request, exc: AuthJWTException):
    return JSONResponse(
        status_code=exc.status_code,
        content={"detail": exc.message}
    )

@app.post('/login')
def login(user: User, Authorize: AuthJWT = Depends()):
    if user.username != "test" or user.password != "test":
        raise HTTPException(status_code=401,detail="Bad username or password")

    # You can define different algorithm when create a token
    access_token = Authorize.create_access_token(subject=user.username,algorithm="HS384")
    refresh_token = Authorize.create_refresh_token(subject=user.username,algorithm="HS512")
    return {"access_token": access_token, "refresh_token": refresh_token}

# In protected route, automatically check incoming JWT
# have algorithm in your `authjwt_decode_algorithms` or not
@app.post('/refresh')
def refresh(Authorize: AuthJWT = Depends()):
    Authorize.jwt_refresh_token_required()

    current_user = Authorize.get_jwt_subject()
    new_access_token = Authorize.create_access_token(subject=current_user)
    return {"access_token": new_access_token}

# In protected route, automatically check incoming JWT
# have algorithm in your `authjwt_decode_algorithms` or not
@app.get('/protected')
def protected(Authorize: AuthJWT = Depends()):
    Authorize.jwt_required()

    current_user = Authorize.get_jwt_subject()
    return {"user": current_user}