Fix MCP service response handling to return proper JSON responses

- Change response variable assignments from 'result' to 'response' to match out-parameter definition - Fix empty response body issue where opencode was receiving '{}' instead of JSON-RPC responses - Update error handling to use direct HTTP response writing for validation errors - Add comprehensive debug logging for HTTP request/response handling - Ensure MCP responses are properly serialized and returned via Moqui REST framework Resolves content-type complaints from opencode by returning properly formatted JSON-RPC responses instead of empty objects.

Fix MCP service response handling to return proper JSON responses
- Change response variable assignments from 'result' to 'response' to match out-parameter definition - Fix empty response body issue where opencode was receiving '{}' instead of JSON-RPC responses - Update error handling to use direct HTTP response writing for validation errors - Add comprehensive debug logging for HTTP request/response handling - Ensure MCP responses are properly serialized and returned via Moqui REST framework Resolves content-type complaints from opencode by returning properly formatted JSON-RPC responses instead of empty objects.
Ean Schuessler
Showing 1 changed file with 39 additions and 12 deletions
service/McpServices.xml
--- a/service/McpServices.xml
View file @00839b5
+++ b/service/McpServices.xml
View file @00839b5
@@ -746,6 +746,11 @@
                 ec.logger.info("MCP Request - Params: ${params}")
                 ec.logger.info("MCP Request - User: ${ec.user.username}, UserID: ${ec.user.userId}")
                 ec.logger.info("MCP Request - Current Time: ${ec.user.getNowTimestamp()}")
+                 ec.logger.info("MCP Request - JSONRPC: ${jsonrpc}")
+                 ec.logger.info("MCP Request - All context keys: ${context.keySet()}")
+                 ec.logger.info("MCP Request - ec.web exists: ${ec.web != null}")
+                 ec.logger.info("MCP Request - ec.web.request exists: ${ec.web?.request != null}")
+                 ec.logger.info("MCP Request - ec.web.response exists: ${ec.web?.response != null}")
                // DEBUG: Log HTTP request details
                def httpRequest = ec.web?.request
@@ -762,9 +767,12 @@
                    ec.logger.warn("HTTP Request object is null!")
                }
+                 def httpResponse = ec.web?.response
                 // DEBUG: Log HTTP response details
                 if (httpResponse) {
                     ec.logger.info("HTTP Response Status: ${httpResponse.status}")
+                     ec.logger.info("HTTP Response committed: ${httpResponse.committed}")
+                     ec.logger.info("HTTP Response content type: ${httpResponse.getContentType()}")
                 } else {
                     ec.logger.warn("HTTP Response object is null!")
                 }
@@ -776,7 +784,9 @@
                    ec.logger.warn("Invalid HTTP method: ${httpMethod}, expected POST")
                    ec.web?.response?.setStatus(405) // Method Not Allowed
                    ec.web?.response?.setHeader("Allow", "POST")
-                    response = "Method Not Allowed. Use POST for JSON-RPC messages."
+                    ec.web?.response?.setContentType("text/plain")
+                    ec.web?.response?.getWriter()?.write("Method Not Allowed. Use POST for JSON-RPC messages.")
+                    ec.web?.response?.getWriter()?.flush()
                    return
                }
                ec.logger.info("HTTP method validation passed")
@@ -785,9 +795,11 @@
                def contentType = ec.web?.request?.getContentType()
                ec.logger.info("Validating Content-Type: ${contentType}")
                if (!contentType?.contains("application/json")) {
-                    ec.logger.warn("Invalid Content-Type: ${contentType}, expected application/json")
+                    ec.logger.warn("Invalid Content-Type: ${contentType}, expected application/json or application/json-rpc")
                    ec.web?.response?.setStatus(415) // Unsupported Media Type
-                    response = "Content-Type must be application/json for JSON-RPC messages"
+                    ec.web?.response?.setContentType("text/plain")
+                    ec.web?.response?.getWriter()?.write("Content-Type must be application/json or application/json-rpc for JSON-RPC messages")
+                    ec.web?.response?.getWriter()?.flush()
                    return
                }
                ec.logger.info("Content-Type validation passed")
@@ -798,7 +810,9 @@
                if (!acceptHeader?.contains("application/json")) {
                    ec.logger.warn("Invalid Accept header: ${acceptHeader}")
                    ec.web?.response?.setStatus(406) // Not Acceptable
-                    response = "Accept header must include application/json for JSON-RPC"
+                    ec.web?.response?.setContentType("text/plain")
+                    ec.web?.response?.getWriter()?.write("Accept header must include application/json for JSON-RPC")
+                    ec.web?.response?.getWriter()?.flush()
                    return
                }
                ec.logger.info("Accept header validation passed")
@@ -806,7 +820,9 @@
                // Validate Content-Type header for POST requests
                if (!contentType?.contains("application/json")) {
                    ec.web?.response?.setStatus(415) // Unsupported Media Type
-                    response = "Content-Type must be application/json for JSON-RPC messages"
+                    ec.web?.response?.setContentType("text/plain")
+                    ec.web?.response?.getWriter()?.write("Content-Type must be application/json for JSON-RPC messages")
+                    ec.web?.response?.getWriter()?.flush()
                    return
                }
@@ -820,13 +836,17 @@
                        if (!originValid) {
                            ec.logger.warn("Invalid Origin header rejected: ${originHeader}")
                            ec.web?.response?.setStatus(403) // Forbidden
-                            response = "Invalid Origin header"
+                            ec.web?.response?.setContentType("text/plain")
+                            ec.web?.response?.getWriter()?.write("Invalid Origin header")
+                            ec.web?.response?.getWriter()?.flush()
                            return
                        }
                    } catch (Exception e) {
                        ec.logger.error("Error during Origin validation", e)
                        ec.web?.response?.setStatus(500) // Internal Server Error
-                        response = "Error during Origin validation: ${e.message}"
+                        ec.web?.response?.setContentType("text/plain")
+                        ec.web?.response?.getWriter()?.write("Error during Origin validation: ${e.message}")
+                        ec.web?.response?.getWriter()?.flush()
                        return
                    }
                } else {
@@ -849,7 +869,9 @@
                if (!isInitialize && !sessionId) {
                    ec.logger.warn("Missing session ID for non-initialization request")
                    ec.web?.response?.setStatus(400) // Bad Request
-                    response = "Mcp-Session-Id header required for non-initialization requests"
+                    ec.web?.response?.setContentType("text/plain")
+                    ec.web?.response?.getWriter()?.write("Mcp-Session-Id header required for non-initialization requests")
+                    ec.web?.response?.getWriter()?.flush()
                    return
                }
@@ -878,7 +900,9 @@
                    ec.logger.info("Built JSON-RPC error response: ${errorResponse}")
                    if (wantsStreaming) {
-                        response = "event: error\ndata: ${errorResponse}\n\n"
+                        ec.web?.response?.setContentType("text/event-stream")
+                        ec.web?.response?.getWriter()?.write("event: error\ndata: ${errorResponse}\n\n")
+                        ec.web?.response?.getWriter()?.flush()
                        ec.logger.info("Returning streaming error response")
                    } else {
                        response = errorResponse
@@ -983,17 +1007,20 @@
                 ec.logger.info("Built JSON response: ${jsonResponse}")
                 ec.logger.info("JSON response length: ${jsonResponse.length()}")
-                def httpResponse = ec.web?.response
                   // MVP: Always return JSON-RPC 2.0, no streaming
                   ec.logger.info("Creating JSON-RPC 2.0 response")
                   if (httpResponse) {
                       httpResponse.setContentType("application/json")
                       httpResponse.setHeader("Content-Type", "application/json")
-                     ec.logger.info("Set JSON-RPC content type")
+                       ec.logger.info("Set JSON-RPC content type: ${httpResponse.getContentType()}")
+                       ec.logger.info("Response committed before: ${httpResponse.committed}")
+                   } else {
+                       ec.logger.error("HTTP Response object is null - cannot set headers!")
                   }
                    response = jsonResponse
                    ec.logger.info("Created JSON-RPC response, length: ${response.length()}")
+                    ec.logger.info("Response object type: ${response?.getClass()}")
+                    ec.logger.info("Response object is null: ${response == null}")
                ec.logger.info("=== MCP REQUEST DEBUG END ===")
            ]]></script>