Added a template method to ResponseTemplateTransformer allowing a sub…

…class to supply extra model elements

src/main/java/com/github/tomakehurst/wiremock/extension/responsetemplating/ResponseTemplateTransformer.java

@@ -108,9 +108,12 @@ public String getName() {
     @Override
     public ResponseDefinition transform(Request request, ResponseDefinition responseDefinition, FileSource files, Parameters parameters) {
         ResponseDefinitionBuilder newResponseDefBuilder = ResponseDefinitionBuilder.like(responseDefinition);
+
         final ImmutableMap<String, Object> model = ImmutableMap.<String, Object>builder()
                 .put("parameters", firstNonNull(parameters, Collections.<String, Object>emptyMap()))
-                .put("request", RequestTemplateModel.from(request)).build();
+                .put("request", RequestTemplateModel.from(request))
+                .putAll(addExtraModelElements(request, responseDefinition, files, parameters))
+                .build();
 
         if (responseDefinition.specifiesTextBodyContent()) {
             Template bodyTemplate = uncheckedCompileTemplate(responseDefinition.getBody());
@@ -150,6 +153,13 @@ public String apply(String input) {
         return newResponseDefBuilder.build();
     }
 
+    /**
+     * Override this to add extra elements to the template model
+     */
+    protected Map<String, Object> addExtraModelElements(Request request, ResponseDefinition responseDefinition, FileSource files, Parameters parameters) {
+        return Collections.emptyMap();
+    }
+
     private void applyTemplatedResponseBody(ResponseDefinitionBuilder newResponseDefBuilder, ImmutableMap<String, Object> model, Template bodyTemplate) {
         String newBody = uncheckedApplyTemplate(bodyTemplate, model);
         newResponseDefBuilder.withBody(newBody);