Adjusting the support of configuration via web.config so that multiple providers can be configured

Author: Jeavon

src/UmbracoFileSystemProviders.Azure/AzureBlobFileSystem.cs

@@ -70,30 +70,31 @@ public AzureBlobFileSystem(string containerName, string rootUrl, string connecti
         /// Initializes a new instance of the <see cref="AzureBlobFileSystem"/> class
         /// from values in application settings.
         /// </summary>
-        public AzureBlobFileSystem()
+        /// <param name="alias">The alias of the provider</param>
+        public AzureBlobFileSystem(string alias)
         {
-            string connectionString = ConfigurationManager.AppSettings[ConnectionStringKey];
+            string connectionString = ConfigurationManager.AppSettings[$"{ConnectionStringKey}:{alias}"];
             if (!string.IsNullOrWhiteSpace(connectionString))
             {
-                string rootUrl = ConfigurationManager.AppSettings[RootUrlKey];
+                string rootUrl = ConfigurationManager.AppSettings[$"{RootUrlKey}:{alias}"];
                 if (string.IsNullOrWhiteSpace(rootUrl))
                 {
                     throw new InvalidOperationException("Azure Storage Root URL is not defined in application settings. The " + RootUrlKey + " property was not defined or is empty.");
                 }
 
-                string containerName = ConfigurationManager.AppSettings[ContainerNameKey];
+                string containerName = ConfigurationManager.AppSettings[$"{ContainerNameKey}:{alias}"];
                 if (string.IsNullOrWhiteSpace(containerName))
                 {
                     containerName = "media";
                 }
 
-                string maxDays = ConfigurationManager.AppSettings[MaxDaysKey];
+                string maxDays = ConfigurationManager.AppSettings[$"{MaxDaysKey}:{alias}"];
                 if (string.IsNullOrWhiteSpace(maxDays))
                 {
                     maxDays = "365";
                 }
 
-                string useDefaultRoute = ConfigurationManager.AppSettings[UseDefaultRootKey];
+                string useDefaultRoute = ConfigurationManager.AppSettings[$"{UseDefaultRootKey}:{alias}"];
                 if (string.IsNullOrWhiteSpace(useDefaultRoute))
                 {
                     useDefaultRoute = "true";