How to set Typo3 v10 site config for the equivalent of wildcards but with one exception? - configuration

Question

How can I set the Typo3 V10 Site Configuration to do this:
Everything incoming go to one site root page:
Except this one subdomain, which goes to a separate root page:
I have a web app based on Typo3 8.7 that I'm trying to upgrade to v10. In the 8.7 app, each customer organisation has a unique subdomain - school1.webapp.com, anotherschool.webapp.com etc., all pointing to the same typo3 site root page. Each time I need to create a new customer, all I have to do is to add a new sys_domain record and a custom plugin picks up the current sys_domain record as the means to separate customer data. A wildcard sys_domain record of *.webapp.com the picks up any misspellings and redirects to a separate page.
The one exception is auth.webapp.com which handles oauth authentication for all customers and goes to a different site root page.
This allows me to add new customers with just a simple form, which adds a new sys_domain record and job finished.
I now need to upgrade to Typo3 v10. I can detect the incoming subdomain to split between customer data easily enough, but I'm having problems with the new Site Configuration tool. All I need is to route auth.webapp.com to one site root page and everything else incoming to another.
My current setup seems to work for getting everything to route to the site root
- Entry point /
- Variant Base: https://%env(HTTP_HOST)%/
Condition: getenv("HTTP_HOST") == "*"
But if I create a second site entry for the auth.webapp.com domain, I just get an FE error of
"Page Not Found - The page did not exist or was inaccessible. Reason: The requested page does not exist"
Entry point https://auth.webapp.com
An entry point of /auth.webapp.com/ results in this subdomain going to the main customers entry point, even though the yaml entry says its pointed to the correct start point.
MAIN SITE - All incoming subdomains except auth.webapp.com
base: /
baseVariants:
-
base: 'https://%env(HTTP_HOST)%/'
condition: 'getenv("HTTP_HOST") == "*"'
errorHandling:
-
errorCode: 404
errorHandler: Page
errorContentSource: 't3://page?uid=13'
-
errorCode: 403
errorHandler: Page
errorContentSource: 't3://page?uid=1'
-
errorCode: 500
errorHandler: Page
errorContentSource: 't3://page?uid=14'
flux_content_types: ''
flux_page_templates: ''
languages:
-
title: English
enabled: true
base: /
typo3Language: default
locale: en_GB.UTF-8
iso-639-1: en
websiteTitle: 'Website Title Name'
navigationTitle: ''
hreflang: en-GB
direction: ''
flag: gb
languageId: 0
rootPageId: 1
websiteTitle: 'Website Title Name'
AUTHENTICATION SITE - just auth.webapp.com
base: 'https://auth.webapp.com/'
flux_content_types: ''
flux_page_templates: ''
languages:
-
title: English
enabled: true
base: /
typo3Language: default
locale: en_GB.UTF-8
iso-639-1: en
websiteTitle: ''
navigationTitle: ''
hreflang: ''
direction: ''
flag: gb-eng
languageId: 0
rootPageId: 11
websiteTitle: 'Website Title'

Answer 1

You should make use of environment variables provided by your webserver in this case.
Setting i.e. AUTHENTICATED as an indicator for anything else than auth.webapp.com would help to filter the base variants for the common configuration condition and make sure that auth.webapp.com would be skipped there.

Answer 2

Jo's answer did the job. I'm posting a little more here to help others.
==============
.htaccess file
==============
<If "%{HTTP_HOST} != 'unique\.domain\.com'">
SetEnv SPECIALNAME_ALLOW allow
</If>
<If "%{HTTP_HOST} == 'unique\.domain\.com'">
SetEnv SPECIALNAME_ALLOW skip
</If>
==============
Typo3 SITE entry for the unique domain
==============
Entry Point - https://unique.domain.com/
Variant Base - https://unique.domain.com/
Variant Condition - getenv("SPECIALNAME_ALLOW ") == "skip"
==============
Typo3 SITE entry for everything else
==============
Entry Point - /
Variant Base - /
Variant Condition - getenv("SPECIALNAME_ALLOW ") == "allow"