Azure Blog Storage: Support for nested containers to upload files (#391)

* Split containerName to get root and sub containers

* Update azure storage docs to point nested containers

Author: sa-es-ir

docs/Media/Readme.md

@@ -24,7 +24,7 @@ The following settings in `appsettings.json` control media upload functionality:
 | AuthenticationMode | string | Authentication method - either `Default` for Microsoft Entra ID or `ConnectionString` for connection string auth |
 | ConnectionString   | string | Azure Storage connection string (only used and mandatory when AuthenticationMode is `ConnectionString`)                          |
 | ServiceUrl         | string | Azure Blob Storage service URL (only used and mandatory when AuthenticationMode is `Default`)                                    |
-| ContainerName      | string | Name of the Azure Storage container to store uploaded files.                                                          |
+| ContainerName      | string | Name of the Azure Storage container to store uploaded files. It can be nested containers as well ``path/to/upload``                                                       |
 | CdnEndpoint | string | Optional CDN endpoint to use for uploaded images. If set, the blog will return this URL instead of the storage account URL for uploaded assets. |
 
 ## Authentication Methods

src/LinkDotNet.Blog.Web/Features/Services/FileUpload/AzureBlobStorageService.cs

@@ -1,10 +1,11 @@
-using System;
-using System.IO;
-using System.Threading.Tasks;
 using Azure.Identity;
 using Azure.Storage.Blobs;
 using Azure.Storage.Blobs.Models;
 using Microsoft.Extensions.Options;
+using System;
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
 
 namespace LinkDotNet.Blog.Web.Features.Services.FileUpload;
 
@@ -23,8 +24,10 @@ public async Task<string> UploadFileAsync(string fileName, Stream fileStream, Up
 
         var containerName = azureBlobStorageConfiguration.Value.ContainerName;
         var client = CreateClient(azureBlobStorageConfiguration.Value);
-        var blobContainerClient = client.GetBlobContainerClient(containerName);
-        var blobClient = blobContainerClient.GetBlobClient(fileName);
+
+        var (rootContainer, subContainer) = SplitContainerName(containerName);
+        var blobContainerClient = client.GetBlobContainerClient(rootContainer);
+        var blobClient = blobContainerClient.GetBlobClient($"{subContainer}/{fileName}");
 
         var blobOptions = new BlobUploadOptions();
         if (options.SetCacheControlHeader)
@@ -39,6 +42,18 @@ public async Task<string> UploadFileAsync(string fileName, Stream fileStream, Up
         return GetAssetUrl(blobClient.Uri.ToString(), azureBlobStorageConfiguration.Value);
     }
 
+    private static (string rootContainer, string subContainer) SplitContainerName(string containerName)
+    {
+        var containerNames = containerName.Split('/', StringSplitOptions.RemoveEmptyEntries);
+
+        if (containerNames.Length == 0)
+            return (string.Empty, string.Empty);
+
+        var rootContainer = containerNames[0];
+        var subContainer = string.Join("/", containerNames.Skip(1));
+        return (rootContainer, subContainer);
+    }
+
     private static BlobServiceClient CreateClient(UploadConfiguration configuration)
     {
         if (configuration.AuthenticationMode == AuthenticationMode.ConnectionString.Key)