Change preview URL generation to happen at preview time based on provider alias

Author: kjac

src/Umbraco.Cms.Api.Management/Controllers/Document/DocumentPreviewUrlController.cs

@@ -1,6 +1,7 @@
 using Asp.Versioning;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
+using Umbraco.Cms.Api.Common.Builders;
 using Umbraco.Cms.Api.Management.Factories;
 using Umbraco.Cms.Api.Management.ViewModels.Document;
 using Umbraco.Cms.Core.Models;
@@ -23,12 +24,30 @@ public DocumentPreviewUrlController(
     }
 
     [MapToApiVersion("1.0")]
-    [HttpGet("preview-urls")]
-    [ProducesResponseType(typeof(IEnumerable<DocumentUrlInfoResponseModel>), StatusCodes.Status200OK)]
-    public async Task<IActionResult> GetPreviewUrls([FromQuery(Name = "id")] HashSet<Guid> ids)
+    [HttpGet("{id:guid}/preview-url")]
+    [ProducesResponseType(typeof(DocumentUrlInfo), StatusCodes.Status200OK)]
+    [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status400BadRequest)]
+    [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status404NotFound)]
+    public async Task<IActionResult> GetPreviewUrl(Guid id, string providerAlias, string? culture, string? segment)
     {
-        IEnumerable<IContent> items = _contentService.GetByIds(ids);
+        IContent? content = _contentService.GetById(id);
+        if (content is null)
+        {
+            return NotFound(new ProblemDetailsBuilder()
+                .WithTitle("Document not found")
+                .WithDetail("The requested document did not exist.")
+                .Build());
+        }
 
-        return Ok(await _documentUrlFactory.CreatePreviewUrlSetsAsync(items));
+        DocumentUrlInfo? previewUrlInfo = await _documentUrlFactory.GetPreviewUrlAsync(content, providerAlias, culture, segment);
+        if (previewUrlInfo is null)
+        {
+            return BadRequest(new ProblemDetailsBuilder()
+                .WithTitle("No preview URL for document")
+                .WithDetail("Failed to produce a preview URL for the requested document.")
+                .Build());
+        }
+
+        return Ok(previewUrlInfo);
     }
 }

src/Umbraco.Cms.Api.Management/Controllers/Preview/EnterPreviewController.cs

@@ -7,6 +7,7 @@
 namespace Umbraco.Cms.Api.Management.Controllers.Preview;
 
 [ApiVersion("1.0")]
+[Obsolete("Do not use this. Preview state is initiated implicitly by the preview URL generation. Scheduled for removal in V18.")]
 public class EnterPreviewController : PreviewControllerBase
 {
     private readonly IPreviewService _previewService;

src/Umbraco.Cms.Api.Management/Factories/DocumentUrlFactory.cs

@@ -1,24 +1,46 @@
+using Microsoft.Extensions.Logging;
+using Umbraco.Cms.Api.Management.Routing;
 using Umbraco.Cms.Api.Management.ViewModels.Document;
 using Umbraco.Cms.Core.Models;
+using Umbraco.Cms.Core.Models.Membership;
 using Umbraco.Cms.Core.Routing;
+using Umbraco.Cms.Core.Security;
+using Umbraco.Cms.Core.Services;
+using Umbraco.Extensions;
 
 namespace Umbraco.Cms.Api.Management.Factories;
 
 public class DocumentUrlFactory : IDocumentUrlFactory
 {
     private readonly IPublishedUrlInfoProvider _publishedUrlInfoProvider;
     private readonly UrlProviderCollection _urlProviders;
+    private readonly IPreviewService _previewService;
+    private readonly IBackOfficeSecurityAccessor _backOfficeSecurityAccessor;
+    private readonly IAbsoluteUrlBuilder _absoluteUrlBuilder;
+    private readonly ILogger<DocumentUrlFactory> _logger;
 
-    public DocumentUrlFactory(IPublishedUrlInfoProvider publishedUrlInfoProvider, UrlProviderCollection urlProviders)
+    public DocumentUrlFactory(
+        IPublishedUrlInfoProvider publishedUrlInfoProvider,
+        UrlProviderCollection urlProviders,
+        IPreviewService previewService,
+        IBackOfficeSecurityAccessor backOfficeSecurityAccessor,
+        IAbsoluteUrlBuilder absoluteUrlBuilder,
+        ILogger<DocumentUrlFactory> logger)
     {
         _publishedUrlInfoProvider = publishedUrlInfoProvider;
         _urlProviders = urlProviders;
+        _previewService = previewService;
+        _backOfficeSecurityAccessor = backOfficeSecurityAccessor;
+        _absoluteUrlBuilder = absoluteUrlBuilder;
+        _logger = logger;
     }
 
     public async Task<IEnumerable<DocumentUrlInfo>> CreateUrlsAsync(IContent content)
     {
         ISet<UrlInfo> urlInfos = await _publishedUrlInfoProvider.GetAllAsync(content);
-        return CreateDocumentUrlInfos(urlInfos);
+        return urlInfos
+            .Select(urlInfo => CreateDocumentUrlInfo(urlInfo, false))
+            .ToArray();
     }
 
     public async Task<IEnumerable<DocumentUrlInfoResponseModel>> CreateUrlSetsAsync(IEnumerable<IContent> contentItems)
@@ -34,28 +56,53 @@ public async Task<IEnumerable<DocumentUrlInfoResponseModel>> CreateUrlSetsAsync(
         return documentUrlInfoResourceSets;
     }
 
-    public Task<IEnumerable<DocumentUrlInfoResponseModel>> CreatePreviewUrlSetsAsync(IEnumerable<IContent> contentItems)
+    public async Task<DocumentUrlInfo?> GetPreviewUrlAsync(IContent content, string providerAlias, string? culture, string? segment)
     {
-        DocumentUrlInfoResponseModel[] documentUrlInfoResourceSets = contentItems.Select(content =>
+        IUrlProvider? provider = _urlProviders.FirstOrDefault(provider => provider.Alias.InvariantEquals(providerAlias));
+        if (provider is null)
+        {
+            _logger.LogError("Could not resolve the URL provider requested for preview: {providerAlias}",  providerAlias);
+            return null;
+        }
+
+        UrlInfo? previewUrlInfo = await provider.GetPreviewUrlAsync(content, culture, segment);
+        if (previewUrlInfo is null)
+        {
+            _logger.LogError("The URL provider: {providerAlias} could not generate a preview URL for content with key: {contentKey}",  providerAlias, content.Key);
+            return null;
+        }
+
+        // must initiate preview state for internal preview URLs
+        if (previewUrlInfo.Url is not null && previewUrlInfo.IsExternal is false)
+        {
+            IUser? currentUser = _backOfficeSecurityAccessor.BackOfficeSecurity?.CurrentUser;
+            if (currentUser is null)
             {
-                IEnumerable<UrlInfo> previewUrls = _urlProviders.SelectMany(provider => provider.GetPreviewUrls(content));
-                return new DocumentUrlInfoResponseModel(content.Key, CreateDocumentUrlInfos(previewUrls));
-            })
-            .ToArray();
+                _logger.LogError("Could not access the current backoffice user while attempting to authenticate for preview.");
+                return null;
+            }
 
-        return Task.FromResult<IEnumerable<DocumentUrlInfoResponseModel>>(documentUrlInfoResourceSets);
+            if (await _previewService.TryEnterPreviewAsync(currentUser) is false)
+            {
+                _logger.LogError("A server error occured, could not initiate an authenticated preview state for the current user.");
+                return null;
+            }
+        }
+
+        return CreateDocumentUrlInfo(previewUrlInfo, previewUrlInfo.IsExternal is false);
     }
 
-    private IEnumerable<DocumentUrlInfo> CreateDocumentUrlInfos(IEnumerable<UrlInfo> urlInfos)
-        => urlInfos
-            .Where(urlInfo => urlInfo.Url is not null)
-            .Select(urlInfo => new DocumentUrlInfo
-            {
-                Culture = urlInfo.Culture,
-                Url = urlInfo.Url!.ToString(),
-                Message = urlInfo.Message,
-                IsExternal = urlInfo.IsExternal,
-                Provider = urlInfo.Provider,
-            })
-            .ToArray();
+    private DocumentUrlInfo CreateDocumentUrlInfo(UrlInfo urlInfo, bool ensureAbsoluteUrl)
+    {
+        var url = urlInfo.Url?.ToString();
+        return new DocumentUrlInfo
+        {
+            Culture = urlInfo.Culture,
+            Url = ensureAbsoluteUrl && url is not null
+                ? _absoluteUrlBuilder.ToAbsoluteUrl(url).ToString()
+                : url,
+            Message = urlInfo.Message,
+            Provider = urlInfo.Provider,
+        };
+    }
 }

src/Umbraco.Cms.Api.Management/Factories/IDocumentUrlFactory.cs

@@ -9,5 +9,5 @@ public interface IDocumentUrlFactory
 
     Task<IEnumerable<DocumentUrlInfoResponseModel>> CreateUrlSetsAsync(IEnumerable<IContent> contentItems);
 
-    Task<IEnumerable<DocumentUrlInfoResponseModel>> CreatePreviewUrlSetsAsync(IEnumerable<IContent> contentItems);
+    Task<DocumentUrlInfo?> GetPreviewUrlAsync(IContent content, string providerAlias, string? culture, string? segment);
 }

src/Umbraco.Cms.Api.Management/Factories/MediaUrlFactory.cs

@@ -40,7 +40,6 @@ public IEnumerable<MediaUrlInfo> CreateUrls(IMedia media) =>
             {
                 Culture = null,
                 Url = _absoluteUrlBuilder.ToAbsoluteUrl(mediaUrl).ToString(),
-                IsExternal = false,
             })
             .ToArray();
 

src/Umbraco.Cms.Api.Management/Factories/ReziseImageUrlFactory.cs

@@ -53,7 +53,6 @@ private IEnumerable<MediaUrlInfo> CreateThumbnailUrls(IEnumerable<string> urls,
                     {
                         Culture = null,
                         Url = _absoluteUrlBuilder.ToAbsoluteUrl(url).ToString(),
-                        IsExternal = false,
                     };
                 }
 
@@ -77,7 +76,6 @@ private IEnumerable<MediaUrlInfo> CreateThumbnailUrls(IEnumerable<string> urls,
             {
                 Culture = null,
                 Url = _absoluteUrlBuilder.ToAbsoluteUrl(relativeUrl).ToString(),
-                IsExternal = false,
             };
         }
     }