Nima - When returning JSON as String assume the string is raw json

Author: rbygrave

http-generator-nima/src/main/java/io/avaje/http/generator/helidon/nima/ControllerMethodWriter.java

@@ -113,8 +113,12 @@ void writeHandler(boolean requestScoped) {
         final var uType = UType.parse(method.returnType());
         writer.append("    result.transferTo(res.outputStream());", uType.shortName()).eol();
       } else if (producesJson()) {
-        final var uType = UType.parse(method.returnType());
-        writer.append("    %sJsonType.toJson(result, JsonOutput.of(res));", uType.shortName()).eol();
+        if (returnTypeString()) {
+          writer.append("    res.send(result); // send raw JSON").eol();
+        } else {
+          final var uType = UType.parse(method.returnType());
+          writer.append("    %sJsonType.toJson(result, JsonOutput.of(res));", uType.shortName()).eol();
+        }
       } else {
         writer.append("    res.send(result);").eol();
       }
@@ -159,6 +163,10 @@ private boolean producesJson() {
         && (method.produces() == null || method.produces().toLowerCase().contains("json"));
   }
 
+  private boolean returnTypeString() {
+    return "java.lang.String".equals(method.returnType().toString());
+  }
+
   private boolean missingServerResponse(List<MethodParam> params) {
     return method.isVoid() && params.stream().noneMatch(p -> "ServerResponse".equals(p.shortType()));
   }