Use fallback image for Og:Image

Author: linkdotnet

src/LinkDotNet.Blog.Web/Features/ShowBlogPost/ShowBlogPostPage.razor

@@ -16,7 +16,7 @@ else
 {
     <PageTitle>@BlogPost.Title</PageTitle>
     <OgData Title="@BlogPost.Title"
-            AbsolutePreviewImageUrl="@BlogPost.PreviewImageUrl"
+            AbsolutePreviewImageUrl="@OgDataImage"
             Description="@(Markdown.ToPlainText(BlogPost.ShortDescription))"
             Keywords="@Tags"></OgData>
     <div class="blog-outer-box">
@@ -53,6 +53,8 @@ else
     private string Tags => BlogPost?.Tags != null
         ? string.Join(",", BlogPost.Tags.Select(b => b.Content))
         : null;
+
+    private string OgDataImage => BlogPost.PreviewImageUrlFallback ?? BlogPost.PreviewImageUrl;
 
     private BlogPost BlogPost { get; set; }
 

tests/LinkDotNet.Blog.UnitTests/Web/Features/ShowBlogPost/ShowBlogPostPageTests.cs

@@ -61,4 +61,31 @@ public void ShouldSetTitleToTag()
         var pageTitle = Render(pageTitleStub.Instance.Parameters.Get(p => p.ChildContent));
         pageTitle.Markup.Should().Be("Title");
     }
+
+    [Theory]
+    [InlineData("url1", null, "url1")]
+    [InlineData("url1", "url2", "url2")]
+    public void ShouldUseFallbackAsOgDataIfAvailable(string preview, string fallback, string expected)
+    {
+        JSInterop.Mode = JSRuntimeMode.Loose;
+        var repositoryMock = new Mock<IRepository<BlogPost>>();
+        var blogPost = new BlogPostBuilder()
+            .WithPreviewImageUrl(preview)
+            .WithPreviewImageUrlFallback(fallback)
+            .Build();
+        repositoryMock.Setup(r => r.GetByIdAsync("1")).ReturnsAsync(blogPost);
+        Services.AddScoped(_ => repositoryMock.Object);
+        Services.AddScoped(_ => Mock.Of<IUserRecordService>());
+        Services.AddScoped(_ => Mock.Of<IToastService>());
+        Services.AddScoped(_ => Mock.Of<AppConfiguration>());
+        this.AddTestAuthorization();
+        ComponentFactories.AddStub<PageTitle>();
+        ComponentFactories.AddStub<Like>();
+        ComponentFactories.AddStub<CommentSection>();
+
+        var cut = RenderComponent<ShowBlogPostPage>(
+            p => p.Add(s => s.BlogPostId, "1"));
+
+        cut.FindComponent<OgData>().Instance.AbsolutePreviewImageUrl.Should().Be(expected);
+    }
 }