How to build Aliyun SMS passwordless sign-in with Python

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 Aliyun 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 Aliyun 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:

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.
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.
Enter the application name, e.g., "Bookstore," and click "Create application".

🎉 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 with Logto

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:

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.

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:

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

Add Aliyun connector

SMS connector is a method used to send one-time passwords (OTPs) for authentication. It enables Phone number verification to support passwordless authentication, including SMS-based registration, sign-in, two-factor authentication (2FA), and account recovery. You can easily connect Aliyun as your SMS provider. With the Logto SMS connector, you can set this up in just a few minutes.

To add a SMS connector, simply follow these steps:

Navigate to Console > Connector > Email and SMS connectors.
To add a new SMS connector, click the "Set up" button and select "Aliyun".
Review the README documentation for your selected provider.
Complete the configuration fields in the "Parameter Configuration" section.
Customize the SMS template using the JSON editor.
Test your configuration by sending a verification code to your Phone number.

note:

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

Set up Aliyun SMS connector

Set up a short message service in Aliyun SMS Console

Create an Aliyun account

Go to the Aliyun website and register your Aliyun account if you don't have one.

Enable and Configure Aliyun Short Message Service

Sign-in with your Aliyun account at the Aliyun website and go to the SMS service console page.
Click the "Open for free" (免费开通) button on the top left of the SMS service page and begin the configuration process.
Read and agree to the "SMS service activation Agreement" (短信服务开通条款) and click "Subscribe to a service" (开通服务) to move on.
You are now on the SMS service console page, go to either "Mainland China" (国内消息) or "Outside Mainland China" (国际/港澳台消息) button on the sidebar per your use case.
Add signature and template following the guidelines, and provide the materials or information required for review.
- Remember to select "Verification Code Message" (验证码) as "Scenario" (适用场景) when filling out the signature application and also "Verification Code Message" (验证码) for "Type" (模板类型) when applying for a template review because we are using these signatures and templates to send verification code. Currently, we do not support sending SMS messages other than verification-code-related text messages.
- Also, use {{code}} as a placeholder where you want to place your digital verification code in template contents.
After submitting your SMS signature and template application, you need to wait for it to take effect. At this point, we can go back to the SMS service console page and send a test SMS. If your signatures and templates are ready for use, you can try them directly; if they are not taking effect yet, Aliyun also provides test templates.
- You may need to recharge a small amount of money before sending test messages.
- You may also be asked to bind a test phone number before sending test messages. For more details, go to "Quick Start" (快速学习) tab from the sidebar of the SMS service console page.

Compose the connector JSON

From the SMS service console page, hover on your avatar in the top right corner and go to "AccessKey Management" (AccessKey 管理), and click "Create AccessKey" (创建 AccessKey). You will get an "AccessKey ID" and "AccessKey Secret" pair after finishing security verification. Please keep them properly.
Go to the "Mainland China" (国内消息) or "Outside Mainland China" (国际/港澳台消息) tab you just visited, you can find "Signature" (签名名称) and "Template Code" (模板 CODE) easily.
- If you want to use the test-only signature and template, go to the "Quick Start" (快速学习) tab instead, and you will find them below "Signature & Templates (For Test Only)".
Fill out the Aliyun SMS Connector settings:
- Fill out the accessKeyId and accessKeySecret fields with access key pairs you've got from step 1.
- Fill out the signName field with "Signature" (签名名称) which is mentioned in step 2. All templates will share this signature name.
- You can add multiple SMS connector templates for different cases. Here is an example of adding a single template:
  - Fill the templateCode field, which is how you can control SMS context, with "Template Code" (模板 CODE) from step 2.
  - Fill out usageType field with either Register, SignIn, ForgotPassword or Generic for different use cases. (usageType is a Logto property to identify the proper use case.) In order to enable full user flows, templates with usageType Register, SignIn, ForgotPassword and Generic are required.

Test Aliyun SMS connector

You can type in a phone number and click on "Send" to see whether the settings can work before "Save and Done".

That's it. Don't forget to Enable connector in sign-in experience.

Config types

Name	Type
accessKeyId	string
accessKeySecret	string
signName	string
templates	Template[]

Template Properties	Type	Enum values
templateCode	string	N/A
usageType	enum string	'Register' \| 'SignIn' \| 'ForgotPassword' \| 'Generic'

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 Aliyun connector should be available now.

Once you create a connector successfully, you can enable phone number-based passwordless login and registration.

Navigate to Console > Sign-in experience > Sign-up and sign-in.
Set up sign-up methods (Optional):
1. Select "Phone number" or "Email or phone number" as the sign-up identifier.
2. "Verify at sign-up" is forced to be enabled. You can also enable "Create a password" on registration.
Set up sign-in methods:
1. Select Phone number as one of sign-in identifiers. You can provide multiple available identifiers (email, phone number, and username).
2. Select "Verification code" and / or "Password" as the authentication factor.
Click "Save changes" and test it in "Live preview".

In addition to registration and login via OTPs, you can also have password recovery and -based security verification enabled, as well as linking Phone number to profile. See End-user flows for more details.

Testing and Validation

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

Create an application in Logto​

Integrate Flask with Logto​

Installation​

Init LogtoClient​

Implement sign-in and sign-out​

Handle authentication status​

Checkpoint: Test your application​

Add Aliyun connector​

Set up Aliyun SMS connector​

Set up a short message service in Aliyun SMS Console​

Create an Aliyun account​

Enable and Configure Aliyun Short Message Service​

Compose the connector JSON​

Test Aliyun SMS connector​

Config types​

Save your configuration​

Enable Aliyun connector in Sign-in Experience​

Testing and Validation​

Further readings​