Fix BodyAsFile to also allow relative paths (#244)

* Read only .json files as static mapping files and fix current folder for BodyAsFile

* include .json again

* LocalFileSystemHandler_ReadResponseBodyAsFile_Throws

* Read array from static mappings folder

* xml soap example

src/WireMock.Net/Handlers/IFileSystemHandler.cs

@@ -10,7 +10,7 @@ namespace WireMock.Handlers
         /// <summary>
         /// Gets the folder where the static mappings are located. For local file system, this would be `{CurrentFolder}/__admin/mappings`.
         /// </summary>
-        /// <returns>The foldername.</returns>
+        /// <returns>The folder name.</returns>
         string GetMappingFolder();
 
         /// <summary>
@@ -37,6 +37,7 @@ namespace WireMock.Handlers
         /// Read a static mapping file as text.
         /// </summary>
         /// <param name="path">The path (folder + filename with .json extension).</param>
+        /// <returns>The file content as text.</returns>
         string ReadMappingFile(string path);
 
         /// <summary>
@@ -45,5 +46,12 @@ namespace WireMock.Handlers
         /// <param name="path">The path (folder + filename with .json extension).</param>
         /// <param name="text">The text.</param>
         void WriteMappingFile(string path, string text);
+
+        /// <summary>
+        /// Read a response body file as text.
+        /// </summary>
+        /// <param name="path">The path or filename from the file to read.</param>
+        /// <returns>The file content as bytes.</returns>
+        byte[] ReadResponseBodyAsFile(string path);
     }
 }

src/WireMock.Net/Handlers/LocalFileSystemHandler.cs

@@ -1,6 +1,6 @@
-using System.Collections.Generic;
+using JetBrains.Annotations;
+using System.Collections.Generic;
 using System.IO;
-using JetBrains.Annotations;
 using WireMock.Validation;
 
 namespace WireMock.Handlers
@@ -58,5 +58,15 @@ namespace WireMock.Handlers
 
             File.WriteAllText(path, text);
         }
+
+        /// <inheritdoc cref="IFileSystemHandler.ReadResponseBodyAsFile"/>
+        public byte[] ReadResponseBodyAsFile(string path)
+        {
+            Check.NotNullOrEmpty(path, nameof(path));
+
+            // In case the path is a filename, the path will be adjusted to the MappingFolder.
+            // Else the path will just be as-is.
+            return File.ReadAllBytes(Path.GetFileName(path) == path ? Path.Combine(GetMappingFolder(), path) : path);
+        }
     }
 }