Fix loading additional Handlebars.Net.Helpers dll's when running application from commandline using 'dotnet run' (#97)

* Fix loading additional Handlebars.Net.Helpers dll's when running application from commandline using 'dotnet run'

* .

* var paths = options.CustomHelperPaths ?? new List<string>

* ...

* fix

Author: StefH

src/Handlebars.Net.Helpers/Compatibility/AppContextHelper.cs

@@ -0,0 +1,16 @@
+using System;
+using System.IO;
+
+namespace HandlebarsDotNet.Helpers.Compatibility;
+
+internal static class AppContextHelper
+{
+    public static string GetBaseDirectory()
+    {
+#if NETSTANDARD1_3_OR_GREATER || NET6_0_OR_GREATER
+        return AppContext.BaseDirectory.TrimEnd(Path.DirectorySeparatorChar);
+#else
+        return AppDomain.CurrentDomain.BaseDirectory.TrimEnd(Path.DirectorySeparatorChar);
+#endif
+    }
+}

src/Handlebars.Net.Helpers/HandlebarsHelpers.cs

@@ -13,6 +13,10 @@
 using HandlebarsDotNet.Helpers.Utils;
 using Stef.Validation;
 using HandlebarsDotNet.Helpers.Models;
+using System.Diagnostics;
+using HandlebarsDotNet.Helpers.Compatibility;
+
+
 #if NETSTANDARD1_3_OR_GREATER || NET46_OR_GREATER || NET6_0_OR_GREATER
 using System.Threading;
 #else
@@ -78,7 +82,36 @@ public static void Register(IHandlebars handlebarsContext, Action<HandlebarsHelp
             { Category.Xslt, "XsltHelpers" }
         };
 
-        var paths = options.CustomHelperPaths ?? new List<string> { Directory.GetCurrentDirectory() };
+
+
+        List<string> paths;
+        if (options.CustomHelperPaths != null)
+        {
+            paths = options.CustomHelperPaths.ToList();
+        }
+        else
+        {
+            paths = new List<string>
+            {
+                Directory.GetCurrentDirectory(),
+                AppContextHelper.GetBaseDirectory(),
+            };
+
+#if !NETSTANDARD1_3_OR_GREATER
+            void Add(string? path, ICollection<string> customHelperPaths)
+            {
+                if (!string.IsNullOrEmpty(path))
+                {
+                    customHelperPaths.Add(path!);
+                }
+            }
+            Add(Path.GetDirectoryName(Assembly.GetEntryAssembly()?.Location), paths);
+            Add(Path.GetDirectoryName(Assembly.GetCallingAssembly().Location), paths);
+            Add(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location), paths);
+            Add(Path.GetDirectoryName(Process.GetCurrentProcess().MainModule?.FileName), paths);
+#endif
+        }
+
         var extraHelpers = PluginLoader.Load(paths, extra, handlebarsContext);
 
         foreach (var item in extraHelpers)

src/Handlebars.Net.Helpers/Options/HandlebarsHelpersOptions.cs

@@ -1,5 +1,4 @@
 using System.Collections.Generic;
-using System.IO;
 using HandlebarsDotNet.Helpers.Enums;
 using HandlebarsDotNet.Helpers.Helpers;
 using HandlebarsDotNet.Helpers.Utils;
@@ -36,20 +35,20 @@ public class HandlebarsHelpersOptions
     /// <summary>
     /// The categories to register. By default all categories are registered. See the WIKI for details.
     /// </summary>
-    public Category[]? Categories { get; set; } = null;
+    public Category[]? Categories { get; set; }
 
     /// <summary>
     /// Used for unit-testing DateTime related functionality.
     /// </summary>
-    public IDateTimeService? DateTimeService { get; set; } = null;
+    public IDateTimeService? DateTimeService { get; set; }
 
     /// <summary>
     /// A Dictionary with additional Custom Helpers (Key = CategoryPrefix, Value = IHelpers)
     /// </summary>
-    public IDictionary<string, IHelpers>? CustomHelpers { get; set; } = null;
+    public IDictionary<string, IHelpers>? CustomHelpers { get; set; }
 
     /// <summary>
-    /// The paths to search for additional helpers. If null, the CurrentDirectory is used.
+    /// The paths to search for additional helpers. If null, the CurrentDirectory and BaseDirectory are used.
     /// </summary>
-    public IReadOnlyList<string>? CustomHelperPaths = new List<string> { Directory.GetCurrentDirectory() };
+    public IReadOnlyList<string>? CustomHelperPaths;
 }

src/Handlebars.Net.Helpers/Plugin/PluginLoader.cs

@@ -6,54 +6,55 @@
 using HandlebarsDotNet.Helpers.Enums;
 using HandlebarsDotNet.Helpers.Helpers;
 
-namespace HandlebarsDotNet.Helpers.Plugin
+namespace HandlebarsDotNet.Helpers.Plugin;
+
+internal static class PluginLoader
 {
-    internal static class PluginLoader
+    public static IDictionary<Category, IHelpers> Load(IEnumerable<string> paths, IDictionary<Category, string> items, params object[] args)
     {
-        public static IDictionary<Category, IHelpers> Load(IEnumerable<string> paths, IDictionary<Category, string> items, params object[] args)
+        var helpers = new Dictionary<Category, IHelpers>();
+
+        var pluginTypes = new List<Type>();
+        try
         {
-            var pluginTypes = new List<Type>();
-            try
+            foreach (var file in paths.Distinct().SelectMany(path => Directory.GetFiles(path, "Handlebars*dll")).Distinct())
             {
-                foreach (var file in paths.SelectMany(path => Directory.GetFiles(path, "*.dll")))
+                try
                 {
-                    try
-                    {
-                        var assembly = Assembly.Load(new AssemblyName
-                        {
-                            Name = Path.GetFileNameWithoutExtension(file)
-                        });
-
-                        pluginTypes.AddRange(GetImplementationTypeByInterface(assembly));
-                    }
-                    catch
+                    var assembly = Assembly.Load(new AssemblyName
                     {
-                        // no-op: just try next .dll
-                    }
-                }
-            }
-            catch
-            {
-                // no-op: file system access possibly denied, don't search for files
-            }
-
+                        Name = Path.GetFileNameWithoutExtension(file)
+                    });
 
-            var helpers = new Dictionary<Category, IHelpers>();
-            foreach (var item in items)
-            {
-                var matchingType = pluginTypes.FirstOrDefault(pt => pt.Name == item.Value);
-                if (matchingType is { })
+                    pluginTypes.AddRange(GetImplementationTypeByInterface(assembly));
+                }
+                catch
                 {
-                    helpers.Add(item.Key, (IHelpers)Activator.CreateInstance(matchingType, args)!);
+                    // Just try next .dll
                 }
             }
-
+        }
+        catch
+        {
+            // File system access possibly denied, don't search for any more files
             return helpers;
         }
 
-        private static IEnumerable<Type> GetImplementationTypeByInterface(Assembly assembly)
+
+        foreach (var item in items)
         {
-            return assembly.GetTypes().Where(t => typeof(IHelpers).IsAssignableFrom(t) && !t.GetTypeInfo().IsInterface);
+            var matchingType = pluginTypes.FirstOrDefault(pt => pt.Name == item.Value);
+            if (matchingType is not null)
+            {
+                helpers.Add(item.Key, (IHelpers)Activator.CreateInstance(matchingType, args)!);
+            }
         }
+
+        return helpers;
+    }
+
+    private static IEnumerable<Type> GetImplementationTypeByInterface(Assembly assembly)
+    {
+        return assembly.GetTypes().Where(t => typeof(IHelpers).IsAssignableFrom(t) && !t.GetTypeInfo().IsInterface);
     }
 }