Implement basic JsonRPC Handler

pkg/jsonrpc/register.go

@@ -0,0 +1,46 @@
+package jsonrpc
+
+import (
+	"context"
+	"fmt"
+	"reflect"
+)
+
+func (h *Handler) Register(subSystemName string, s any) {
+	subSystem := reflect.ValueOf(s)
+
+	for i := 0; i < subSystem.NumMethod(); i++ {
+		m := subSystem.Type().Method(i)
+
+		funcType := m.Func.Type()
+
+		if funcType.NumIn() != 3 {
+			panic(fmt.Errorf("2 parameters are required %v", funcType.NumIn()))
+		}
+		if funcType.In(1) != reflect.TypeOf(new(context.Context)).Elem() {
+			panic(fmt.Errorf("the first argument needs to be a context.Context instead of %v ", funcType.In(1)))
+		}
+		if funcType.In(2).Kind() != reflect.Struct {
+			panic("the second argument needs to be a struct")
+		}
+
+		if funcType.NumOut() != 2 {
+			panic("2 return types are required")
+		}
+		if reflect.TypeOf(new(error)).Implements(funcType.Out(1)) {
+			panic("the second return type needs to be a error")
+		}
+
+		name := m.Name
+		if subSystemName != "" {
+			name = subSystemName + "." + name
+		}
+
+		h.methods[name] = method{
+			handlerFunc: m.Func,
+			subSystem:   subSystem,
+			inType:      funcType.In(2),
+			outType:     funcType.Out(0),
+		}
+	}
+}