General: Allow direct linking to self-registering courses

[pal03377]

Checklist

General

• I tested all changes and their related features with all corresponding user types on a test server.

• Language: I followed the guidelines for inclusive, diversity-sensitive, and appreciative language.
• I chose a title conforming to the naming conventions for pull requests.

Server

• I followed the coding and design guidelines.
• I added multiple integration tests (Spring) related to the features (with a high test coverage).
• I added pre-authorization annotations according to the guidelines and checked the course groups for all new REST Calls (security).
• I implemented the changes with a good performance and prevented too many database calls.
• I documented the Java code using JavaDoc style.

Client

• I followed the coding and design guidelines and ensured that the layout is responsive.
• Following the theming guidelines, I specified colors only in the theming variable files and checked that the changes look consistent in both the light and the dark theme.
• I added multiple integration tests (Jest) related to the features (with a high test coverage), while following the test guidelines.
• I added authorities to all new routes and checked the course groups for displaying navigation elements (links, buttons).
• I documented the TypeScript code using JSDoc style.
• I added multiple screenshots/screencasts of my UI changes.
• I translated all newly inserted strings into English and German.

Motivation and Context

This PR implements the suggested change from #6171.
In short, it provides a way to link to self-registration course even if students are not yet registered. Previously, Artemis would show an error message. Now, this PR provides a registration page.

Description

• Changed the behavior of the /api/courses/{courseId}/for-dashboard endpoint in case of an authentication error: If the user could self-register, but is not registered yet, this endpoint now 302-redirects to /api/courses/{courseId}/for-registration.
• Added a new endpoint /api/courses/{courseId}/for-registration, which returns reduced information about the course. The endpoint is only accessible for students (and higher roles) who are allowed to self-register in the respective course. The endpoint redirects to /api/courses/{courseId}/for-dashboard if the user is already registered.
• Refactored the check whether a student can register for a course. Now it's included in the CourseService and more thoroughly tested.
• Added a registration page for a single course.

• Refactored the client-side code for course registration: Now the actual registration isn't coupled to the course registration overview page anymore, but to the registration button.
• Added new redirects:
  • From /courses/{courseId} and /courses/{courseId}/* to /courses/{courseId}/register, if the user can register, but is not yet registered.
  • From /courses/{courseId}/register to /courses/{courseId}, if the user is already registered.

Steps for Testing

Prerequisites:

• 1 Course with self-registration enabled

• 1 Student who is not yet registered in that course

Suggestion: Use course with ID 117 "6.0 Testing Session Course 1" on TS1 and your personal TUM login to test. Usually, the course should have self-registration enabled and you probably are not registered with your personal login yet.

1. Log in to Artemis
2. Navigate to https:///courses/{courseId}, e.g. https://artemis-test1.artemis.in.tum.de/courses/117
3. Note that you are being redirected to https:///courses/{courseId}/register

4. Click the Register button on the page.
5. Note that a confirmation dialog opens up and that dialog includes the registration confirmation message from the course settings.

6. Cancel and re-open the dialog to verify that this works as well.
7. Confirm the registration in the dialog.
8. Note that you are redirected to the actual course page and that you get a "Registration successful" message.

9. Now go to the registration page explicitly: Enter https:///courses/{courseId}/register, e.g. https://artemis-test1.artemis.in.tum.de/courses/117/register, in the URL bar of your browser.
10. Note that you are being redirected to the course page again, as you are already registered.

New Testing Steps: Online Courses

Prerequisites:

• An Online Course (e.g. https://artemis-test2.artemis.in.tum.de/course-management/8563). Make sure that the Online Course checkmark is checked in the Edit configuration of the course (also disables the Self-Registration checkbox).
• An instructor of that course (e.g. artemis_test_user_11)
• A student (e.g. artemis_test_user_1)

Steps:

• Ensure that the student is not registered to the online course (e.g. on https://artemis-test2.artemis.in.tum.de/course-management/8563/groups/students)
• With the student, go to artemisUrl/courses/<your-course-id> (e.g. https://artemis-test2.artemis.in.tum.de/courses/8563).
• Verify that an error message is shown. If you see two alerts, you are observing Development: Course access authorization alert sometimes appears twice #6382, which is not part of this PR.
• Go to artemisUrl/courses/<your-course-id>/register (e.g. https://artemis-test2.artemis.in.tum.de/courses/8563/register).
• Verify that an error message is shown.
• Manually register the student to the course.
• Verify that the error messages from before do not appear.

Review Progress

Code Review

• Review 1
• Review 2
• Review 3

Manual Tests

• Test 1
• Test 2
• Test 3

Test Coverage

File	Line %	Confirmation
alert.service.ts	72.64%
AuthorizationCheckService.java	75.56%	✅
course-overview.component.ts	75.52%	✅
course-prerequisites-button.component.ts	100.00%	✅
course-registration-button.component.ts	92.31%	✅
course-registration-detail.component.ts	88.46%	✅
course-registration.component.ts	86.67%	✅
Course.java	84.55%
CourseResource.java	91.18%	✅ (CourseTestService)

Screenshots

Registration for course with prerequisites:

[laadvo]

Reapprove code.

[julian-christl]

Reapprove code

[Strohgelaender]

re-aprove

[simon-hng]

Tested additional steps on TS1

[frederik-kt]

Tested additional steps for online courses on TS2. Works as expected.

[FelixTJDietrich]

Tested again on ts1, also with the additional testing steps. Works as expected.