2308: Return server errors in json for API

[bahaaTuffaha]

Short description

The API should always return JSON, even if an error occurs.

Proposed changes

• Added an is_api_request helper that checks request.resolver_match.app_name against "api", falling back to a request.path prefix check when the URL couldn't be resolved.
• Added a render_error_response function that returns a JsonResponse for API requests and otherwise falls back to HttpResponse wrapping the existing render_error_template.
• Updated handler400, handler403, handler404, handler500, and csrf_failure to use render_error_response instead of constructing the response classes directly.
• Changed the return type for the handlers from HttpResponseBadRequest, HttpResponseForbidden, HttpResponseNotFound, and HttpResponseServerError to the generic HttpResponse.

Side effects

None.

Faithfulness to issue description and design

There are no intended deviations from the issue and design.

How to test

• Launch the server in non debug mode I used this command (Debug=0):

source .venv/bin/activate

DJANGO_SETTINGS_MODULE=integreat_cms.core.docker_settings \
INTEGREAT_CMS_DEBUG=0 \
INTEGREAT_CMS_SECRET_KEY=dummy \
DYLD_FALLBACK_LIBRARY_PATH=/opt/homebrew/lib \
integreat-cms-cli runserver --insecure localhost:8000

Note: DYLD_FALLBACK_LIBRARY_PATH is a macOS/Homebrew workaround for cairocffi skip it on Linux.

• Test non-existent url paths like:
  • For the Api : http://localhost:8000/api/v3/non-existing
  • For any other pages: http://localhost:8000/regions/foo

Resolved issues

Fixes: #2308

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Pull Request Review Guidelines

[MizukiTemma]

Looks good, thank you 😸