如何在 Laravel 中自动创建子域

Question

I am creating a SaaS app using Laravel and I am trying to create subdomains for each user signup. For example,

1. User comes to www.somewebsite.com and signs up
2. During the signup, the user provides their business name eg mybiz
3. I want my Laravel app to dynamically create a dynamic subdomain mybiz.somewebsite.com
4. Whenever user logs into the website they are automatically redirected to mybiz.somewebsite.com and they stay on this URL during the entire session.

At no time I as an admin would like to create a subdomain manually. I am using Apache on Ubuntu for my Laravel install.

Answer 1

First create a wildcard subdomain on your server so your laravel app handles all subdomain requests. Then create a global Middleware for your app which extracts the subdomain from the request url and process as appropriate. That way, both https://example.com and https://{username}.example.com is processed by your app and you can do what you wish with the {username}

Answer 2

There are many ways to do it, a lot depends on what you are trying to achieve here.

I assume you don't want to dynamically create and give away real host names/subdomains, so I would go with creating wildcard DNS record pointing to the machine. Single A record pointing to IP address will do the trick, simply add asterisk "*" in front instead of specifying a hostname.

Domain records would then look like this:

┌──────────────────────────────┬─────────────┬──────────────────────────────────┐
│    HOSTNAME                  │    TYPE     │    POINT TO                      │
│──────────────────────────────│─────────────│──────────────────────────────────│
│    some-domain.com           │      A      │    SERVER IP ADDRESS             │
│    *.some-domain.com         │      A      │    SERVER IP ADDRESS             │
│    wwww.some-domain.com      │    CNAME    │    some-domain.com               │

With that you basically redirect all traffic from any variation of the hostname to single address and allow it to manage it. Wildcard record like that can be overriden only by another more specific record, so it will identify as whatever.some-domain.com and anything.some-domain.com and allow you to fully manage it virtually without the need to add any more records.

Now you want to tell your web server to take control over all those possible addresses. With Apache you can do that by adding new virtual hosts to configuration, as many as you like and need, or you can add just one general and route everything to your Laravel application and let it handle it all on it's own. Something like that would work:

 <VirtualHost *:80>
   ServerName your-domain.com
   ServerAlias *.your-domain.com
   DocumentRoot /var/www/laravel/app
 </VirtualHost>

At this point you can do whatever you like - because you handle all the traffic you can route visitors to any subdomain. You can setup some environmental variables in Apache to know exactly what subdomain was used when someone visit the app, or use PHP built-ins and read the address with globals like $_SERVER['HTTP_HOST'] .

I am sure Laravel provides more than enough utilities to handle everything out of the box, but there is no need to depend on frameworks, handling the traffic can be done even with pseudo-code like this:

<?php
if ($_SERVER['HTTP_HOST'] !== CurrentUser::get_personal_subdomain()) {
  http_response_code(301);
  header('Location: '. Router::random_address());
  exit;
}