Removed duplicate code and add note for obsolete method

[sofietoft]

Description

Removed duplicate code.
Added a note about the obsolete GetAll() method on the _domainService.

Type of suggestion

• Typo/grammar fix
• Updated outdated content
• New content
• Updates related to a new version
• Other

Product & version (if relevant)

15.0.0

[bergmania]

That entire example should be updated to something like

using Umbraco.Cms.Core.PublishedCache;
using Umbraco.Cms.Core.Routing;
using Umbraco.Cms.Core.Services;

namespace RoutingDocs.ContentFinders;

public class My404ContentFinder : IContentLastChanceFinder
{
    private readonly IDomainService _domainService;
    private readonly IPublishedContentCache _publishedContentCache;

    public My404ContentFinder(
        IDomainService domainService,
        IPublishedContentCache publishedContentCache)
    {
        _domainService = domainService;
        _publishedContentCache = publishedContentCache;
    }

    public async Task<bool> TryFindContent(IPublishedRequestBuilder contentRequest)
    {
        // Find the root node with a matching domain to the incoming request
        var allDomains = (await _domainService.GetAllAsync(true)).ToList();
        var domain = allDomains
            .FirstOrDefault(f => f.DomainName == contentRequest.Uri.Authority
                                    || f.DomainName == $"https://{contentRequest.Uri.Authority}"
                                    || f.DomainName == $"http://{contentRequest.Uri.Authority}");

        var siteId = domain != null ? domain.RootContentId : allDomains.Any() ? allDomains.FirstOrDefault()?.RootContentId : null;


        var siteRoot = _publishedContentCache.GetById(false, siteId ?? -1);

        if (siteRoot is null)
        {
            return false;
        }

        // Assuming the 404 page is in the root of the language site with alias fourOhFourPageAlias
        var notFoundNode = siteRoot.Children()?.FirstOrDefault(f => f.ContentType.Alias == "fourOhFourPageAlias");

        if (notFoundNode is not null)
        {
            contentRequest.SetPublishedContent(notFoundNode);
        }

        // Return true or false depending on whether our custom 404 page was found
        return contentRequest.PublishedContent is not null;
    }
}