from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()

reusable_oauth2 = OAuth2(
    flows={
        "password": {
            "tokenUrl": "token",
            "scopes": {"read:users": "Read the users", "write:users": "Create users"},
        }
    },
    auto_error=False,
)


class User(BaseModel):
    username: str

from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()

reusable_oauth2 = OAuth2(
    flows={
        "password": {
            "tokenUrl": "token",
            "scopes": {"read:users": "Read the users", "write:users": "Create users"},
        }
    }
)


class User(BaseModel):
    username: str

from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()

reusable_oauth2 = OAuth2(
    flows={
        "password": {
            "tokenUrl": "token",
            "scopes": {"read:users": "Read the users", "write:users": "Create users"},
        }
    },
    description="OAuth2 security scheme",
    auto_error=False,
)


class User(BaseModel):

class OAuthFlowImplicit(OAuthFlow):
    authorizationUrl: str


class OAuthFlowPassword(OAuthFlow):
    tokenUrl: str


class OAuthFlowClientCredentials(OAuthFlow):
    tokenUrl: str


class OAuthFlowAuthorizationCode(OAuthFlow):
    authorizationUrl: str
    tokenUrl: str


class OAuthFlows(BaseModelWithConfig):
    implicit: Optional[OAuthFlowImplicit] = None

            }
        },
        "components": {
            "securitySchemes": {
                "OAuth2PasswordBearer": {
                    "type": "oauth2",
                    "flows": {"password": {"scopes": {}, "tokenUrl": "token"}},
                }
            },
        },

                },
            },
            "securitySchemes": {
                "OAuth2PasswordBearer": {
                    "type": "oauth2",
                    "flows": {"password": {"scopes": {}, "tokenUrl": "token"}},
                }
            },
        },

                                    "me": "Read information about the current user.",
                                    "items": "Read items.",
                                },
                                "tokenUrl": "token",
                            }
                        },
                    }
                },
            },
        }

                "OAuth2PasswordBearer": {
                    "type": "oauth2",
                    "flows": {
                        "password": {
                            "scopes": {},
                            "tokenUrl": "token",
                        }
                    },
                }
            },
        },

    * New docs about `root_path` and `servers` in [Additional Servers](https://fastapi.tiangolo.com/advanced/behind-a-proxy/#additional-servers).
    * Update OAuth2 examples to use a relative URL for `tokenUrl="token"` to make sure those examples keep working as-is even when behind a reverse proxy.
    * Initial PR [#1596](https://github.com/tiangolo/fastapi/pull/1596) by [@rkbeatss](https://github.com/rkbeatss).