Request handling

src/main/java/dev/selimaj/session/Session.java

@@ -1,9 +1,12 @@
 package dev.selimaj.session;
 
 import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.TextNode;
 
+import dev.selimaj.session.types.SessionResult;
 import dev.selimaj.session.types.Message;
 import dev.selimaj.session.types.Method;
+import dev.selimaj.session.types.MethodHandler;
 
 import java.net.URI;
 import java.net.http.HttpClient;
@@ -52,6 +55,19 @@ public final class Session {
         return listener.request(ws, method.getName(), req, method.getResClass());
     }
 
+    <Req extends JsonNode, Res extends JsonNode, Err extends JsonNode> void onRequest(Method<Req, Res, Err> method,
+            MethodHandler<Req> handler) {
+        MethodHandler<JsonNode> wrapper = (id, value) -> {
+            try {
+                return handler.handle(id, listener.mapper.treeToValue(value, method.getReqClass()));
+            } catch (Exception e) {
+                return SessionResult.error(TextNode.valueOf(e.getMessage()));
+            }
+        };
+
+        this.listener.methods.put(method.getName(), wrapper);
+    }
+
     public void close() throws Exception {
         ws.sendClose(0, "Session closed");
     }