Implemented template renderer.

framework/src/Volo.Abp.Core/Volo/Abp/Localization/CultureHelper.cs

@@ -29,5 +29,12 @@ namespace Volo.Abp.Localization
                 CultureInfo.CurrentUICulture = currentUiCulture;
             });
         }
+
+        public static string GetBaseCultureName(string cultureName)
+        {
+            return cultureName.Contains("-")
+                ? cultureName.Left(cultureName.IndexOf("-", StringComparison.Ordinal))
+                : cultureName;
+        }
     }
 }

framework/src/Volo.Abp.Localization/Volo/Abp/Localization/AbpDictionaryBasedStringLocalizer.cs

@@ -104,7 +104,7 @@ namespace Volo.Abp.Localization
             //Try to get from same language dictionary (without country code)
             if (cultureName.Contains("-")) //Example: "tr-TR" (length=5)
             {
-                var strLang = Resource.Contributors.GetOrNull(GetBaseCultureName(cultureName), name);
+                var strLang = Resource.Contributors.GetOrNull(CultureHelper.GetBaseCultureName(cultureName), name);
                 if (strLang != null)
                 {
                     return strLang;
@@ -168,7 +168,7 @@ namespace Volo.Abp.Localization
                 //Overwrite all strings from the language based on country culture
                 if (cultureName.Contains("-"))
                 {
-                    Resource.Contributors.Fill(GetBaseCultureName(cultureName), allStrings);
+                    Resource.Contributors.Fill(CultureHelper.GetBaseCultureName(cultureName), allStrings);
                 }
             }
 
@@ -178,12 +178,7 @@ namespace Volo.Abp.Localization
             return allStrings.Values.ToImmutableList();
         }
 
-        protected virtual string GetBaseCultureName(string cultureName)
-        {
-            return cultureName.Contains("-")
-                ? cultureName.Left(cultureName.IndexOf("-", StringComparison.Ordinal))
-                : cultureName;
-        }
+        
 
         public class CultureWrapperStringLocalizer : IStringLocalizer, IStringLocalizerSupportsInheritance
         {

framework/src/Volo.Abp.TextTemplating/Volo/Abp/TextTemplating/ITemplateContentProvider.cs

@@ -1,9 +1,13 @@
 using System.Threading.Tasks;
+using JetBrains.Annotations;
 
 namespace Volo.Abp.TextTemplating
 {
     public interface ITemplateContentProvider
     {
-        Task<string> GetContentOrNullAsync(string templateName, string cultureName);
+        Task<string> GetContentOrNullAsync(
+            [NotNull] string templateName,
+            [CanBeNull] string cultureName = null
+        );
     }
 }

framework/src/Volo.Abp.TextTemplating/Volo/Abp/TextTemplating/TemplateContentProvider.cs

@@ -1,4 +1,5 @@
 using System.Threading.Tasks;
+using JetBrains.Annotations;
 using Volo.Abp.DependencyInjection;
 
 namespace Volo.Abp.TextTemplating
@@ -14,7 +15,9 @@ namespace Volo.Abp.TextTemplating
             _templateDefinitionManager = templateDefinitionManager;
         }
 
-        public async Task<string> GetContentOrNullAsync(string templateName, string cultureName)
+        public async Task<string> GetContentOrNullAsync(
+            [NotNull] string templateName, 
+            [CanBeNull] string cultureName = null)
         {
             var template = _templateDefinitionManager.Get(templateName);
 

framework/src/Volo.Abp.TextTemplating/Volo/Abp/TextTemplating/VirtualFiles/VirtualFileTemplateContributor.cs

@@ -1,14 +1,18 @@
 using System;
 using System.Collections.Generic;
+using System.Globalization;
 using JetBrains.Annotations;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.FileProviders;
+using Volo.Abp.Localization;
 using Volo.Abp.VirtualFileSystem;
 
 namespace Volo.Abp.TextTemplating.VirtualFiles
 {
     public class VirtualFileTemplateContributor : ITemplateContributor
     {
+        public TemplateDefinition TemplateDefinition { get; private set; }
+
         private readonly string _virtualPath;
         private IVirtualFileProvider _virtualFileProvider;
         private volatile Dictionary<string, string> _templateDictionary;
@@ -23,21 +27,46 @@ namespace Volo.Abp.TextTemplating.VirtualFiles
         public void Initialize(TemplateContributorInitializationContext context)
         {
             _virtualFileProvider = context.ServiceProvider.GetRequiredService<IVirtualFileProvider>();
+            TemplateDefinition = context.TemplateDefinition;
         }
 
         public string GetOrNull([CanBeNull] string cultureName = null)
         {
-            var dictionary = GetTemplateDictionary();
+            //TODO: Refactor: Split implementation based on single file or dictionary of culture-specific contents
 
             if (cultureName == null)
             {
-                return dictionary.GetOrDefault("__default");
+                cultureName = CultureInfo.CurrentUICulture.Name;
+            }
+
+            var dictionary = GetTemplateDictionary();
+
+            var content = dictionary.GetOrDefault(cultureName);
+            if (content != null)
+            {
+                return content;
+            }
+
+            if (cultureName.Contains("-"))
+            {
+                var baseCultureName = CultureHelper.GetBaseCultureName(cultureName);
+                content = dictionary.GetOrDefault(baseCultureName);
+                if (content != null)
+                {
+                    return content;
+                }
             }
-            else
+
+            if (TemplateDefinition.DefaultCultureName != null)
             {
-                return dictionary.GetOrDefault(cultureName) ??
-                       dictionary.GetOrDefault("__default");
+                content = dictionary.GetOrDefault(TemplateDefinition.DefaultCultureName);
+                if (content != null)
+                {
+                    return content;
+                }
             }
+
+            return dictionary.GetOrDefault("__default");
         }
 
         private Dictionary<string, string> GetTemplateDictionary()

framework/test/Volo.Abp.TextTemplating.Tests/Volo/Abp/TextTemplating/SampleTemplates/WelcomeEmail/en.tpl

@@ -1 +1 @@
-Welcome to the abp.io!
+Welcome {{name}} to the abp.io!

framework/test/Volo.Abp.TextTemplating.Tests/Volo/Abp/TextTemplating/SampleTemplates/WelcomeEmail/tr.tpl

@@ -1 +1 @@
-abp.io'ya hoşgeldiniz!
+Merhaba {{name}}, abp.io'ya hoşgeldiniz!

framework/test/Volo.Abp.TextTemplating.Tests/Volo/Abp/TextTemplating/TemplateRenderer_Tests.cs

@@ -1,4 +1,5 @@
-using System.Threading.Tasks;
+using System.Collections.Generic;
+using System.Threading.Tasks;
 using Shouldly;
 using Xunit;
 
@@ -19,7 +20,85 @@ namespace Volo.Abp.TextTemplating
             var content = await _templateRenderer.RenderAsync(
                 TestTemplates.ForgotPasswordEmail
             );
+
             content.ShouldBe("Please click to the following link to get an email to reset your password!");
         }
+
+        [Fact]
+        public async Task Should_Get_Rendered_Localized_Template_Content_With_Different_Cultures()
+        {
+            (await _templateRenderer.RenderAsync(
+                TestTemplates.WelcomeEmail,
+                model: new
+                {
+                    name = "John"
+                },
+                cultureName: "en"
+            )).ShouldBe("Welcome John to the abp.io!");
+
+            (await _templateRenderer.RenderAsync(
+                TestTemplates.WelcomeEmail,
+                model: new
+                {
+                    name = "John"
+                },
+                cultureName: "tr"
+            )).ShouldBe("Merhaba John, abp.io'ya hoşgeldiniz!");
+
+            //"en-US" fallbacks to "en" since "en-US" doesn't exists and "en" is the fallback culture
+            (await _templateRenderer.RenderAsync(
+                TestTemplates.WelcomeEmail,
+                model: new
+                {
+                    name = "John"
+                },
+                cultureName: "en-US"
+            )).ShouldBe("Welcome John to the abp.io!");
+
+            //"fr" fallbacks to "en" since "fr" doesn't exists and "en" is the default culture
+            (await _templateRenderer.RenderAsync(
+                TestTemplates.WelcomeEmail,
+                model: new
+                {
+                    Name = "John" //Intentionally written as PascalCase since Scriban supports it
+                },
+                cultureName: "fr"
+            )).ShouldBe("Welcome John to the abp.io!");
+        }
+
+        [Fact]
+        public async Task Should_Get_Rendered_Localized_Template_Content_With_Stronly_Typed_Model()
+        {
+            (await _templateRenderer.RenderAsync(
+                TestTemplates.WelcomeEmail,
+                model: new WelcomeEmailModel("John"),
+                cultureName: "en"
+            )).ShouldBe("Welcome John to the abp.io!");
+        }
+
+        [Fact]
+        public async Task Should_Get_Rendered_Localized_Template_Content_With_Dictionary_Model()
+        {
+            (await _templateRenderer.RenderAsync(
+                TestTemplates.WelcomeEmail,
+                model: new Dictionary<string, object>() { { "name", "John" } },
+                cultureName: "en"
+            )).ShouldBe("Welcome John to the abp.io!");
+        }
+
+        private class WelcomeEmailModel
+        {
+            public string Name { get; set; }
+
+            public WelcomeEmailModel()
+            {
+
+            }
+
+            public WelcomeEmailModel(string name)
+            {
+                Name = name;
+            }
+        }
     }
 }

framework/test/Volo.Abp.TextTemplating.Tests/Volo/Abp/TextTemplating/TestTemplateDefinitionProvider.cs

@@ -6,7 +6,8 @@
         {
             context.Add(
                 new TemplateDefinition(
-                    TestTemplates.WelcomeEmail
+                    TestTemplates.WelcomeEmail,
+                    defaultCultureName: "en"
                 ).AddVirtualFiles("/SampleTemplates/WelcomeEmail")
             );
 

framework/test/Volo.Abp.TextTemplating.Tests/Volo/Abp/TextTemplating/VirtualFiles/VirtualFileTemplateContributor_Tests.cs

@@ -21,11 +21,11 @@ namespace Volo.Abp.TextTemplating.VirtualFiles
 
             contributor
                 .GetOrNull("en")
-                .ShouldBe("Welcome to the abp.io!");
+                .ShouldBe("Welcome {{name}} to the abp.io!");
 
             contributor
                 .GetOrNull("tr")
-                .ShouldBe("abp.io'ya hoşgeldiniz!");
+                .ShouldBe("Merhaba {{name}}, abp.io'ya hoşgeldiniz!");
         }
 
         [Fact]