Make resource lookup behavior overridable (#266)

.gitignore

@@ -30,4 +30,5 @@ nuget.exe
 *.*sdf
 *.ipch
 *.sln.ide
-*launchSettings.json
+*launchSettings.json
+**/Resources/*.Designer.cs

Localization.sln

@@ -1,6 +1,6 @@
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 14
-VisualStudioVersion = 14.0.23107.0
+VisualStudioVersion = 14.0.25420.1
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "src", "src", "{FB313677-BAB3-4E49-8CDB-4FA4A9564767}"
 EndProject

samples/LocalizationSample/Startup.cs

@@ -37,7 +37,8 @@ namespace LocalizationSample
 #if !NETCOREAPP1_0
             supportedCultures.Add(new CultureInfo("zh-CHT"));
 #endif
-            var options = new RequestLocalizationOptions {
+            var options = new RequestLocalizationOptions
+            {
                 DefaultRequestCulture = new RequestCulture("en-US"),
                 SupportedCultures = supportedCultures,
                 SupportedUICultures = supportedCultures

src/Microsoft.Extensions.Localization/ResourceManagerStringLocalizerFactory.cs

@@ -50,6 +50,70 @@ namespace Microsoft.Extensions.Localization
             }
         }
 
+        /// <summary>
+        /// Gets the resource prefix used to look up the resource.
+        /// </summary>
+        /// <param name="typeInfo">The type of the resource to be looked up.</param>
+        /// <returns>The prefix for resource lookup.</returns>
+        protected virtual string GetResourcePrefix(TypeInfo typeInfo)
+        {
+            if (typeInfo == null)
+            {
+                throw new ArgumentNullException(nameof(typeInfo));
+            }
+
+            return GetResourcePrefix(typeInfo, _hostingEnvironment.ApplicationName, _resourcesRelativePath);
+        }
+
+        /// <summary>
+        /// Gets the resource prefix used to look up the resource.
+        /// </summary>
+        /// <param name="typeInfo">The type of the resource to be looked up.</param>
+        /// <param name="baseNamespace">The base namespace of the application.</param>
+        /// <param name="resourcesRelativePath">The folder containing all resources.</param>
+        /// <returns>The prefix for resource lookup.</returns>
+        /// <remarks>
+        /// For the type "Sample.Controllers.Home" if there's a resourceRelativePath return
+        /// "Sample.Resourcepath.Controllers.Home" if there isn't one then it would return "Sample.Controllers.Home".
+        /// </remarks>
+        protected virtual string GetResourcePrefix(TypeInfo typeInfo, string baseNamespace, string resourcesRelativePath)
+        {
+            if (typeInfo == null)
+            {
+                throw new ArgumentNullException(nameof(typeInfo));
+            }
+
+            if (string.IsNullOrEmpty(baseNamespace))
+            {
+                throw new ArgumentNullException(nameof(baseNamespace));
+            }
+
+            return string.IsNullOrEmpty(resourcesRelativePath)
+                ? typeInfo.FullName
+                : baseNamespace + "." + resourcesRelativePath + TrimPrefix(typeInfo.FullName, baseNamespace + ".");
+        }
+
+        /// <summary>
+        /// Gets the resource prefix used to look up the resource.
+        /// </summary>
+        /// <param name="baseResourceName">The name of the resource to be looked up</param>
+        /// <param name="baseNamespace">The base namespace of the application.</param>
+        /// <returns>The prefix for resource lookup.</returns>
+        protected virtual string GetResourcePrefix(string baseResourceName, string baseNamespace)
+        {
+            if (string.IsNullOrEmpty(baseResourceName))
+            {
+                throw new ArgumentNullException(nameof(baseResourceName));
+            }
+
+            var locationPath = baseNamespace == _hostingEnvironment.ApplicationName ?
+                baseNamespace + "." + _resourcesRelativePath :
+                baseNamespace + ".";
+            baseResourceName = locationPath + TrimPrefix(baseResourceName, baseNamespace + ".");
+
+            return baseResourceName;
+        }
+
         /// <summary>
         /// Creates a <see cref="ResourceManagerStringLocalizer"/> using the <see cref="Assembly"/> and
         /// <see cref="Type.FullName"/> of the specified <see cref="Type"/>.
@@ -67,10 +131,7 @@ namespace Microsoft.Extensions.Localization
             var assembly = typeInfo.Assembly;
 
             // Re-root the base name if a resources path is set
-            var baseName = string.IsNullOrEmpty(_resourcesRelativePath)
+            var baseName = GetResourcePrefix(typeInfo);
-                ? typeInfo.FullName
-                : _hostingEnvironment.ApplicationName + "." + _resourcesRelativePath
-                    + TrimPrefix(typeInfo.FullName, _hostingEnvironment.ApplicationName + ".");
 
             return _localizerCache.GetOrAdd(baseName, _ =>
                 new ResourceManagerStringLocalizer(
@@ -96,7 +157,7 @@ namespace Microsoft.Extensions.Localization
 
             location = location ?? _hostingEnvironment.ApplicationName;
 
-            baseName = location + "." + _resourcesRelativePath + TrimPrefix(baseName, location + ".");
+            baseName = GetResourcePrefix(baseName, location);
 
             return _localizerCache.GetOrAdd($"B={baseName},L={location}", _ =>
             {