Configure JSON encoding format options (#21)

Author: mattt

Sources/MCP/Base/Messages.swift

@@ -1,4 +1,5 @@
-import Foundation
+import class Foundation.JSONDecoder
+import class Foundation.JSONEncoder
 
 private let jsonrpc = "2.0"
 
@@ -130,9 +131,12 @@ final class TypedRequestHandler<M: Method>: RequestHandlerBox, @unchecked Sendab
 
     override func callAsFunction(_ request: Request<AnyMethod>) async throws -> Response<AnyMethod>
     {
+        let encoder = JSONEncoder()
+        let decoder = JSONDecoder()
+
         // Create a concrete request from the type-erased one
-        let data = try JSONEncoder().encode(request.params)
-        let params = try JSONDecoder().decode(M.Parameters.self, from: data)
+        let data = try encoder.encode(request.params)
+        let params = try decoder.decode(M.Parameters.self, from: data)
         let typedRequest = Request<M>(id: request.id, method: M.name, params: params)
 
         // Handle with concrete type
@@ -141,8 +145,8 @@ final class TypedRequestHandler<M: Method>: RequestHandlerBox, @unchecked Sendab
         // Convert result to AnyMethod response
         switch response.result {
         case .success(let result):
-            let resultData = try JSONEncoder().encode(result)
-            let resultValue = try JSONDecoder().decode(Value.self, from: resultData)
+            let resultData = try encoder.encode(result)
+            let resultValue = try decoder.decode(Value.self, from: resultData)
             return Response(id: response.id, result: resultValue)
         case .failure(let error):
             return Response(id: response.id, error: error)

Sources/MCP/Base/Transports.swift

@@ -3,9 +3,6 @@ import Logging
 import SystemPackage
 
 import struct Foundation.Data
-import struct Foundation.Date
-import class Foundation.JSONDecoder
-import class Foundation.JSONEncoder
 
 /// Protocol defining the transport layer for MCP communication
 public protocol Transport: Actor {

Sources/MCP/Server/Server.swift

@@ -205,7 +205,8 @@ public actor Server {
                             "Error processing message", metadata: ["error": "\(error)"])
                         let response = AnyMethod.response(
                             id: requestID ?? .random,
-                            error: error as? Error ?? Error.internalError(error.localizedDescription)
+                            error: error as? Error
+                                ?? Error.internalError(error.localizedDescription)
                         )
                         try? await send(response)
                     }
@@ -260,7 +261,11 @@ public actor Server {
         guard let connection = connection else {
             throw Error.internalError("Server connection not initialized")
         }
-        let responseData = try JSONEncoder().encode(response)
+        let encoder = JSONEncoder()
+        encoder.outputFormatting = [.sortedKeys, .withoutEscapingSlashes]
+
+        let responseData = try encoder.encode(response)
+
         if let responseStr = String(data: responseData, encoding: .utf8) {
             try await connection.send(responseStr)
         }
@@ -271,7 +276,12 @@ public actor Server {
         guard let connection = connection else {
             throw Error.internalError("Server connection not initialized")
         }
-        let notificationData = try JSONEncoder().encode(notification)
+
+        let encoder = JSONEncoder()
+        encoder.outputFormatting = [.sortedKeys, .withoutEscapingSlashes]
+
+        let notificationData = try encoder.encode(notification)
+
         if let notificationStr = String(data: notificationData, encoding: .utf8) {
             try await connection.send(notificationStr)
         }