Module development and code questions

A quick demo using PHPOffice/PhpSpreadsheet. 

https://github.com/PHPOffice/PhpSpreadsheet

https://phpspreadsheet.readthedocs.io/en/develop/

I'd link to restrict character of username when register. I found module "username_validation". But it's can make only blacklist, while I want to make white list.

Please help. (I use drupal 8.5)

Hello,

i stop for a simple code, i think.
But i don't understand why i have the problem !

I send a message to user to send back a code to redirect after to a form where he have to put personal information.

In my x.routing.yml, he have :

"x.depot_lecode:
  path: '/depot_lecode/{code}'
  defaults:
    _controller: '\Drupal\x\Controller\XController::depot_lecode'
[...]
x.formulaire:
   path: '/formulaire/{nid}/{did}'
   defaults:
      _form: '\Drupal\x\Form\formulaire'
      did: 0
[..]"

First off, my apologies if this post is in the wrong forum.  I have a client that runs a separate section of their website on Drupal 8 and I'd like to be able to query an API on the Drupal site and pull the search results into their corporate search page, which is hosted on a different CMS platform.  I'm not the developer of the Drupal site and don't have experience developing for Drupal, I'm just wondering how difficult of a customization is this?  I'm well aware it would also depend on the skill level and experience of the developer, so this is just a general inquiry.

I am working on a custom module that has custom content types. The idea is that the content created within Drupal should be automatically sent to an external server via an API.

Let's say the module on install creates a content type "Service" with its own fields and all. When I create a new node of the type "Service" through the UI, I want to be able to listen to this event from the custom module code and execute a function that will retreive the data from the new node and send it over the API.

How can I "listen" to new specific content created?

Hey everybody,

is there a Module wich generates the weekday out of an date-field?

Fred-Eric