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For our new friends:

Logto is an Auth0 alternative designed for modern apps and SaaS products. It offers both Cloud and Open-source services to help you quickly launch your identity and management (IAM) system. Enjoy authentication, authorization, and multi-tenant management all in one.

We recommend starting with a free development tenant on Logto Cloud. This allows you to explore all the features easily.

In this article, we will go through the steps to quickly build the Hugging Face sign-in experience (user authentication) with Python and Logto.

Prerequisites

  • A running Logto instance. Check out the introduction page to get started.
  • Basic knowledge of Python.
  • A usable Hugging Face account.

Create an application in Logto​

Logto is based on OpenID Connect (OIDC) authentication and OAuth 2.0 authorization. It supports federated identity management across multiple applications, commonly called Single Sign-On (SSO).

To create your Traditional web application, simply follow these steps:

  1. Open the Logto Console. In the "Get started" section, click the "View all" link to open the application frameworks list. Alternatively, you can navigate to Logto Console > Applications, and click the "Create application" button. Get started
  2. In the opening modal, click the "Traditional web" section or filter all the available "Traditional web" frameworks using the quick filter checkboxes on the left. Click the "Flask" framework card to start creating your application. Frameworks
  3. Enter the application name, e.g., "Bookstore," and click "Create application".

πŸŽ‰ Ta-da! You just created your first application in Logto. You'll see a congrats page which includes a detailed integration guide. Follow the guide to see what the experience will be in your application.

Integrate Flask SDK​

tip:
  • The example uses Flask, but the concepts are the same for other frameworks.
  • The Python sample project is available on our Python SDK repo.
  • Logto SDK leverages coroutines, remember to use await when calling async functions.

Installation​

Execute in the project root directory:

pip install logto # or `poetry add logto` or whatever you use

Init LogtoClient​

First, create a Logto config:

client.py
from logto import LogtoClient, LogtoConfig

client = LogtoClient(
LogtoConfig(
endpoint="https://you-logto-endpoint.app", # Replace with your Logto endpoint
appId="replace-with-your-app-id",
appSecret="replace-with-your-app-secret",
),
)
tip:

You can find and copy "App Secret" from application details page in Admin Console:

App Secret

Also replace the default memory storage with a persistent storage, for example:

client.py
from logto import LogtoClient, LogtoConfig, Storage
from flask import session
from typing import Union

class SessionStorage(Storage):
def get(self, key: str) -> Union[str, None]:
return session.get(key, None)

def set(self, key: str, value: Union[str, None]) -> None:
session[key] = value

def delete(self, key: str) -> None:
session.pop(key, None)

client = LogtoClient(
LogtoConfig(...),
storage=SessionStorage(),
)

See Storage for more details.

Implement sign-in and sign-out​

In your web application, add a route to properly handle the sign-in request from users. Let's use /sign-in as an example:

flask.py
@app.route("/sign-in")
async def sign_in():
# Get the sign-in URL and redirect the user to it
return redirect(await client.signIn(
redirectUri="http://localhost:3000/callback",
))

Replace http://localhost:3000/callback with the callback URL you set in your Logto Console for this application.

If you want to show the sign-up page on the first screen, you can set interactionMode to signUp:

flask.py
@app.route("/sign-in")
async def sign_in():
return redirect(await client.signIn(
redirectUri="http://localhost:3000/callback",
interactionMode="signUp", # Show the sign-up page on the first screen
))

Now, whenever your users visit http://localhost:3000/sign-in, it will start a new sign-in attempt and redirect the user to the Logto sign-in page.

Note Creating a sign-in route isn't the only way to start a sign-in attempt. You can always use the signIn method to get the sign-in URL and redirect the user to it.

After the user makes a signing-out request, Logto will clear all user authentication information in the session.

To clean up the Python session and Logto session, a sign-out route can be implemented as follows:

flask.py
@app.route("/sign-out")
async def sign_out():
return redirect(
# Redirect the user to the home page after a successful sign-out
await client.signOut(postLogoutRedirectUri="http://localhost:3000/")
)

Handle authentication status​

In Logto SDK, we can use client.isAuthenticated() to check the authentication status, if the user is signed in, the value will be true, otherwise, the value will be false.

Here we also implement a simple home page for demonstration:

  • If the user is not signed in, show a sign-in button;
  • If the user is signed in, show a sign-out button.
@app.route("/")
async def home():
if client.isAuthenticated() is False:
return "Not authenticated <a href='/sign-in'>Sign in</a>"
return "Authenticated <a href='/sign-out'>Sign out</a>"

Checkpoint: Test your application​

Now, you can test your application:

  1. Run your application, you will see the sign-in button.
  2. Click the sign-in button, the SDK will init the sign-in process and redirect you to the Logto sign-in page.
  3. After you signed in, you will be redirected back to your application and see the sign-out button.
  4. Click the sign-out button to clear token storage and sign out.

Add Hugging Face connector​

To enable quick sign-in and improve user conversion, connect with Flask as an identity provider. The Logto social connector helps you establish this connection in minutes by allowing several parameter inputs.

To add a social connector, simply follow these steps:

  1. Navigate to Console > Connectors > Social Connectors.
  2. Click "Add social connector" and select "Hugging Face".
  3. Follow the README guide and complete required fields and customize settings.

Connector tab

note:

If you are following the in-place Connector guide, you can skip the next section.

Set up Hugging Face OAuth app​

Sign in with Hugging Face account​

Go to the Hugging Face website and sign in with your Hugging Face account. You may register a new account if you don't have one.

Create an OAuth app in the Hugging Face​

Follow the Creating an oauth app guide, and register a new application.

In the creation process, you will need to provide the following information:

  • Application Name: The name of your application.
  • Homepage URL: The URL of your application's homepage or landing page.
  • Logo URL: The URL of your application's logo.
  • Scopes: The scopes allowed for the OAuth app. For Hugging Face connector, usually use profile to get the user's profile information and email to get the user's email address. Ensure these scopes are allowed in your Hugging Face OAuth app if you want to use them.
  • Redirect URI: The URL to redirect the user to after they have authenticated. You can find the redirect URI in the Logto Admin Console when you're creating a Hugging Face connector or in the created Hugging Face connector details page.

Managing Hugging Face OAuth apps​

Go to the Connected Applications page, you can add, edit or delete existing OAuth apps. You can also find Client ID and generate App secrets in corresponding OAuth app settings pages.

Configure your connector​

Fill out the clientId and clientSecret field with Client ID and App Secret you've got from OAuth app detail pages mentioned in the previous section.

scope is a space-delimited list of Hugging Face supported scopes. If not provided, scope defaults to be profile. For Hugging Face connector, the scope you may want to use is profile and email. profile scope is required to get the user's profile information, and email scope is required to get the user's email address. Ensure you have allowed these scopes in your Hugging Face OAuth app (configured in Create an OAuth app in the Hugging Face section).

Config types​

NameType
clientIdstring
clientSecretstring
scopestring

Save your configuration​

Double check you have filled out necessary values in the Logto connector configuration area. Click "Save and Done" (or "Save changes") and the Hugging Face connector should be available now.

Enable Hugging Face connector in Sign-in Experience​

Once you create a social connector successfully, you can enable it as a "Continue with Hugging Face" button in Sign-in Experience.

  1. Navigate to Console > Sign-in experience > Sign-up and sign-in.
  2. (Optional) Choose "Not applicable" for sign-up identifier if you need social login only.
  3. Add configured Hugging Face connector to the "Social sign-in" section.

Sign-in Experience tab

Testing and Validation​

Return to your Python app. You should now be able to sign in with Hugging Face. Enjoy!

Further readings​

End-user flows: Logto provides a out-of-the-box authentication flows including MFA and enterprise SSO, along with powerful APIs for flexible implementation of account settings, security verification, and multi-tenant experience.

Authorization: Authorization defines the actions a user can do or resources they can access after being authenticated. Explore how to protect your API for native and single-page applications and implement Role-based Access Control (RBAC).

Organizations: Particularly effective in multi-tenant SaaS and B2B apps, the organization feature enable tenant creation, member management, organization-level RBAC, and just-in-time-provisioning.

Customer IAM series Our serial blog posts about Customer (or Consumer) Identity and Access Management, from 101 to advanced topics and beyond.