Overview

Casdoor is a UI-first centralized authentication / Single-Sign-On (SSO) platform based on OAuth 2.0 / OIDC.

Casdoor serves both the web UI and the login requests from the application users.

Casdoor features:

1. Front-end and back-end separate architecture, developed by Golang, Casdoor supports high concurrency, provides web-based managing UI and supports multiple languages(Chinese, English).

2. Casdoor supports Github, Google, QQ, WeChat third-party applications login, and support the extension of third-party login with plugins.

3. With Casbin based authorization management, Casdoor supports ACL, RBAC, ABAC, RESTful accessing control models.

4. Phone verification code, email verification code and forget password features.

5. Accessing logs auditing and recording.

6. Alibaba Cloud, Tencent Cloud, Qiniu Cloud image CDN cloud storage.

7. Customizable register, login, and forget password pages.

8. Casdoor supports integration with existing systems using db sync method, users can transition to Casdoor smoothly.

9. Casdoor supports mainstream databases: MySQL, PostgreSQL, SQL Server etc, and support the extension of new database with plugins.

How it works:

Step 0 (Pre-knowledge)

1. Casdoor’s authorization process is built upon the OAuth 2.0 protocol, therefore it’s highly recommended to take a brief look at how indeed does OAuth 2.0 works. An introduction of OAuth 2.0.

Step 1 (Authorization Request)

Your Application (could be a website or whatever) should compose an URL in this format endpoint/login/oauth/authorize?client_id=xxx&response_type=code&redirect_uri=xxx&scope=read&state=xxx. In the URL replace endpoint with your Casdoor’s host URL, and replace xxx with your own info.

Hints

How to fill out the xxx parts?

• For client_id: you can find this under each single Application

• For redirect_uri: you should set this to your own Application’s callback URL, with this info, Casdoor can know where to send info back after authorization

• For state: you should fill this out with your Application name

The Application will speak to the user: “Hey, now I need some resources and I need your permission to take these resources, you mind go to this URL and fill out your username and password for me?”

With the correctly composed URL, your Application will make a user launch a request to this URL, and the Authorization Request is done.

Step 2 (Authorization Grant)

This step is straightforward: the user is redirected to the URL composed above, and the user should see the login page from Casdoor.
By typing the correct username and credential into the login form, Casdoor now knows the identity of the user, and is about to send two keywords: code and state back to the callback URL set in Step 1.

The user opens the URL and provides the credentials to Casdoor. Casdoor will say: “Looking good ~ this is the user (who is authorizing the Application to get the code and state) I know in my database, and I will send the code and state back to the Application using the callback URL (redirect_uri)”

With these two keywords send back to your Application, the authrization is now granted to the app, and thus Authorization Grant is completed.

tip

Casdoor also provides third-party login, in this case, you will not see the credentials enter page but a list of third-party providers. You can login to your app using these providers, with Casdoor as a middle layer (middleware).

Step 3 (Authorization Grant)

In this step, your Application already has the code in hand from Step 2, and it will speak to Casdoor: “Hey, now the user agreed to give me the code, you wanna check this code out and give me the access_token?”

Step 4 (Access Token)

In this step, Casdoor speaks back to the Application: “You know what, this code seems legit, you must be the right Application. Come, here’s the access_token.”
With this code, that Casdoor knows that it is an authorized Application (authorization given by the correct user in Step 2) trying to get the access_token (will be used later to get more useful things).

Step 5 (Access Token)

In this step, your Application says: “Nice one, just got the fresh-and-tasty access_token, I can now use it to get something more valuable from the Resource Server!”

And your Application turns to the Resource Server: “Hey buddy, wanna check this access_token out? I got this from Casdoor and you want to see if this is the correct one you had with Casdoor?”

Step 6 (Protected Resource)

The Resource Server speaks back to your Application: “Not bad ~ it seems just like the one I had with Casdoor, and Casdoor says whoever hold this access_token can have these Protected Resource. Now, you take it!”

And this is basically how Casdoor works with your Application.

Hint

Casdoor can play both Authorization Server and Resource Server parts, i.e. Casdoor authorizes our Application to get resources (e.g. usually the current logged in user’s info) from Casdoor’s database.

Online demo

Casdoor

Here is an online demo deployed by Casbin.

• Casdoor official demo

Global admin login:

• Username: admin
• Password: 123

Casbin-OA

Casbin-OA is one of Casbin web apps. It uses Casdoor as authentication.

• Casbin-OA
• Source code: https://github.com/casbin/casbin-oa

Casnode

Casnode is the official forum developed by Casbin community.

It uses Casdoor as authentication platform and manage members.

• Casnode
• Source code: https://github.com/casbin/casnode

Architecture

Casdoor contains 2 parts: