added description method and description tag

framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Basic/Themes/Basic/Layouts/Empty.cshtml

@@ -39,7 +39,10 @@
     <meta http-equiv="X-UA-Compatible" content="ie=edge">
 
     <title>@pageTitle</title>
-
+    @if (ViewBag.Description!=null)
+    {
+        <meta name="description" content="@ViewBag.Description" />
+    }
     <abp-style-bundle name="@BasicThemeBundles.Styles.Global" />
 
     @await Component.InvokeAsync(typeof(WidgetStylesViewComponent))

modules/docs/src/Volo.Docs.Web/Pages/Documents/Project/Index.cshtml

@@ -19,6 +19,7 @@
     ViewBag.FluidLayout = true;
     Layout = ThemeManager.CurrentTheme.GetEmptyLayout();
     PageLayout.Content.Title = Model.DocumentName?.Replace("-", " ");
+    ViewBag.Description = Model.GetDescription();
 }
 @section styles {
     <abp-style-bundle name="@typeof(IndexModel).FullName">

modules/docs/src/Volo.Docs.Web/Pages/Documents/Project/Index.cshtml.cs

@@ -2,7 +2,9 @@ using System;
 using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
+using System.Text.RegularExpressions;
 using System.Threading.Tasks;
+using System.Web;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.Rendering;
 using Microsoft.Extensions.Logging;
@@ -64,7 +66,7 @@ namespace Volo.Docs.Pages.Documents.Project
         public DocumentParametersDto DocumentPreferences { get; set; }
 
         public DocumentRenderParameters UserPreferences { get; set; } = new DocumentRenderParameters();
-        
+
         public bool FullSearchEnabled { get; set; }
 
         private readonly IDocumentAppService _documentAppService;
@@ -591,5 +593,17 @@ namespace Volo.Docs.Pages.Documents.Project
                 }
             }
         }
+
+        public string GetDescription()
+        {
+            var startIndex = Document.Content.IndexOf("<p>", StringComparison.Ordinal);
+            var lastIndex = Document.Content.IndexOf("</p>", StringComparison.Ordinal);
+            var description = Document.Content.Substring(startIndex,lastIndex);
+
+            Regex rx = new Regex("<[^>]*>");
+            description = rx.Replace(description, "");
+
+            return description.Truncate(200);
+        }
     }
 }