Description

URL Shortener is an open-source web service for shortening URLs and based on .NET 6 and Blazor Server techologies.

URL shortener consist of two parts:

• User area
• Admin area

User area is a simple page that working as redirection mechanism.

• User type shortened link in browser
• Goes to the redirector's page (file Redirector.razor)
• Redirector.razor redirect user to target URL

Admin area has functionality described bellow:

• Authentication flow using Auth0
• Reducing links into short link wit 7-simbolic auto-generated or predefined alias
• Editing target URL in created short link
• Support multilanguage interface (English, Russian, Belarusian)

Also Shortener collect data about rederections for each link: count of redirections, agent info etc.

Interface of application

Settigs-up and Run local instance

1. Prepare a SQL-like database.
   • Setup an SQL Server or any other SQL-like database (for example Azure SQL Edge good one for ARM processers and so on)
   • Create the database with pds (or any other name on your choise).
   • Update the database connection string in theConnectionStrings:DefaultConnection field of shortener/Shortener/Itbeard.Shortener/appsettings.json file.
   • Migration of the database to the current state will occur automatically the first time you run the project.
2. Set up authentication via Auth0.
   • Register an account on Auth0 service.
   • Create application Application with type Single Page Application
   • Update shortener settings in shortener/Shortener/Itbeard.Shortener/appsettings.json file:
     • Auth0:Domain = value of Domain field from Auth0 application
     • Auth0:ClientId = value of Client ID field from Auth0 application
     • Auth0:ClientSecret = value of Client Secret field from Auth0 application
   • Update settings of Auth0 application:
     • In field Allowed Callback URLs set https://localhost:5001//admin/callback.
     • In field Allowed Logout URLs set https://localhost:5001.
   • In Auth0, delete the database on the Authentication - Database tab or remove your Application link to this database, so that you only authenticate through Google. You can control the login methods on the Connections tab of your application in Auth0.
   • Add a Rule in which you explicitly specify which emails have access to authorization in the application:
     • Go to Auth Pipeline - Rules menu.
     • Add rule in accordance with Whitelist template and update rule by emails that are allowed to access the authorization.
     • Or create a rule with the following code (if the Whitelist template is suddenly not founded in Auth0):

function userWhitelist(user, context, callback) {

  // Access should only be granted to verified users.
  if (!user.email || !user.email_verified) {
    return callback(new UnauthorizedError('Access denied.'));
  }

  const whitelist = [ 'user1@example.com', 'user2@example.com' ]; //authorized users
  const userHasAccess = whitelist.some(
    function (email) {
      return email === user.email;
    });

  if (!userHasAccess) {
    return callback(new UnauthorizedError('Access denied.'));
  }

  callback(null, user, context);
}

3. Add URL of your Shortener instanse in to field AppUrl in shortener/Shortener/Itbeard.Shortener/appsettings.json file.
4. Build and run project Itbeard.Shortener.
5. Open https://localhost:5001/admin in your browser - this URL is the entry point to the admin interface of the Shortener.

Useful links

• Instructions of how to setting up Auth0 in Blazor: https://auth0.com/blog/securing-blazor-webassembly-apps/