Module development and code questions

Hello,

When a user navigates to /how I like to check if the user is logged in before displaying the content. I like to define _user_is_logged_in: 'TRUE' access requirement in the routing.yml file to check if the current user is logged in. But I am getting an error when clearing the cache. 

demo.routing.yml:

demo.how:

  path: /how

  defaults:

    _controller: Drupal\demo\Controller\HelloWorldController::how

    _title: 'How page!'

  requirements:

  _user_is_logged_in: 'TRUE'

Error:

 Hello,

[Sorry for my English]

I need to create pdf files from a full HTML to keep my CSS files. I use a template in my module. But if I clear cache on a admin page, my template use admin theme, whereas if I clear cache on a front page, this is the front theme that it used...

How can I choose the theme to use in my template to still have the same theme used by my pdf files?

I want to use my template only with my front theme, and I search a way to fix it.

My code with comments in my controller:

The `SYSTEM` table was deprecated in MYSQL 8.0.

'SYSTEM` table used in _OAUTH_COMMON_VERSION (OAUTH_COMMON.MODULE) in DRUPAL OAUTH 1.0.

Please help me what is the alternative way.

Hello,

I am new to module development. 

If the user is not logged in, I expect the user to redirect to the login page but it is not working. 

\web\modules\custom\demo\src\EventSubscriber:

Hello, 

I like to give content editors permission to promote content for basic page entities. 

Created a content editor user (people -> add user).

Created a yml file at the module base directory. 

touch demo.permissions.yml

can promote nodes:

  title: 'Can promote content'

  description: 'user can change promotion fields on content.'

demo.module file:

We changed the value of "temporary_maximum_age" set in config/default/system.file.yml as below.

temporary_maximum_age 21600 → 60

This is so that files in temporary state can be deleted immediately by running the "Deletes temporary files" cron.

What I want to ask is the scope of influence of this setting change.
Our understanding is that there is no impact other than the deletion time of temporary files, but is there any other impact?

I would appreciate it if you could answer. Thank you.