JSON RPC2 implementation

README.md

@@ -24,6 +24,7 @@ The supported functionality contains:
 ## Packages
 
 - `api`: global API interface definitions and eebus service configuration
+- `com/jsonrpc2`: provides an JSON RPC2 implementation, to communicate with systems not written in Golang
 - `features/client`: provides feature helpers with the local SPINE feature having the client role and the remote SPINE feature being the server for easy access to commonly used functions
 - `features/server`: provides feature helpers with the local SPINE feature having the server role for easy access to commonly used functions
 - `service`: central package which provides access to SHIP and SPINE. Use this to create the EEBUS service, its configuration and connect to remote EEBUS services
@@ -42,7 +43,7 @@ Services with implemented use cases will be implemented in different repositorie
 #### First Run
 
 ```sh
-go run cmd/hems/main.go 4715
+go run examples/hems/main.go 4715
 ```
 
 `4715` is the example server port that this process should use
@@ -52,7 +53,7 @@ The certificate and key and the local SKI will be generated and printed. You sho
 #### General Usage
 
 ```sh
-Usage: go run cmd/hems/main.go <serverport> <remoteski> <certfile> <keyfile>
+Usage: go run examples/hems/main.go <serverport> <remoteski> <certfile> <keyfile>
 ```
 
 - `remoteski` is the SKI of the remote device or service you want to connect to
@@ -64,7 +65,7 @@ Usage: go run cmd/hems/main.go <serverport> <remoteski> <certfile> <keyfile>
 #### First Run
 
 ```sh
-go run cmd/hems/main.go 4715
+go run examples/hems/main.go 4715
 ```
 
 `4715` is the example server port that this process should use
@@ -74,7 +75,7 @@ The certificate and key and the local SKI will be generated and printed. You sho
 #### General Usage
 
 ```sh
-Usage: go run cmd/evse/main.go <serverport> <remoteski> <certfile> <keyfile>
+Usage: go run examples/evse/main.go <serverport> <remoteski> <certfile> <keyfile>
 ```
 
 - `remoteski` is the SKI of the remote device or service you want to connect to

com/README.md

@@ -0,0 +1,3 @@
+# Overview
+
+This folder contains multiple communication APIs for services that are not written in Golang and need to communicate with a Go service running this stack and use the public API for interaction.

com/jsonrpc2/README.md

@@ -0,0 +1 @@
+This is currently a placeholder file as this folder will host the jsonrpc2 API interface and implementation

examples/remote/util.go

@@ -25,11 +25,23 @@ func isExportedOrBuiltinType(t reflect.Type) bool {
 	return token.IsExported(t.Name()) || t.PkgPath() == ""
 }
 
+// json.Marshall won't marshall error types, marshall as string
+func errorAsJson(v reflect.Value) interface{} {
+	if v.IsNil() {
+		// passthrough nil as nil, otherwise nil.(error) will panic
+		return nil
+	} else {
+		return v.Interface().(error).Error()
+	}
+}
+
 func transformReturnValues(values []reflect.Value) []interface{} {
 	result := make([]interface{}, len(values))
 
 	for i, e := range values {
-		switch e.Type() {
+		valueType := e.Type()
+
+		switch valueType {
 		case reflect.TypeFor[spineapi.DeviceRemoteInterface]():
 			result[i] = e.Interface().(spineapi.DeviceRemoteInterface).Address()
 		case reflect.TypeFor[[]spineapi.DeviceRemoteInterface]():
@@ -51,12 +63,18 @@ func transformReturnValues(values []reflect.Value) []interface{} {
 			}
 			result[i] = transformedValues
 		default:
-			result[i] = e.Interface()
+			switch {
+			case valueType.Implements(reflect.TypeFor[error]()):
+				result[i] = errorAsJson(e)
+			default:
+				result[i] = e.Interface()
+			}
 		}
 	}
 
 	return result
 }
+
 func WriteKey(cert tls.Certificate, path string) error {
 	file, err := os.Create(path)
 	if err != nil {