Add/Edit dashlet not possible

[staypekos]

Describe the bug

The add form ends with failure "The url must not be external." no matter what is used as url. Same as update form even without any change.

The problem is probably in InternalUrlValidator#21.

As I remember the relative url (e.g. monitoring/tactical; without initial /) worked to add dashlet (was also possible to finish with full url, but the dashlet does not work after that). AFAIK relative url does not have the scheme so it's not good idea to compare it with app scheme.
Tested scenarios (URL -> result):
monitoring/tactical -> fail on second part (scheme is NULL)
/monitoring/tactical -> fail on first part (relativeUrl is empty string)
https://monitoring/tactical -> "works" - add new dashlet which is not working, because getRelativeUrl() returns only "tactical"
https://icinga.company.my/monitoring/tactical -> still fail on first part (relativeUrl is empty string) (maybe here is the mistake for much longer time?)

To Reproduce

1. Go to Dashboard -> Add Dashlet
2. Fill required fields
3. Push "Add To Dashboard" button

or

1. Go to Dashboard -> Settings
2. Select dashlet to edit
3. Push "Update Dashlet" button

Expected behavior

The form accepts some relative or absolute url.

Screenshots

Your Environment

• Icinga Web 2 version and modules (System - About): 2.11.3
• Web browser used: Google Chrome 108
• Icinga 2 version used (icinga2 --version): r2.13.6-1
• PHP version used (php --version): 7.4.33
• Server operating system and version: Debian 11

[ValeDaRold]

Hi!
We encountered the same problem also with Icingaweb2 version 2.10.4.

[tbauriedel]

ref/NC/773400