Add CQRS marshalers (#78)

components/cqrs/marshaler_json.go

@@ -8,7 +8,8 @@ import (
 )
 
 type JSONMarshaler struct {
-	NewUUID func() string
+	NewUUID      func() string
+	GenerateName func(v interface{}) string
 }
 
 func (m JSONMarshaler) Marshal(v interface{}) (*message.Message, error) {
@@ -40,7 +41,11 @@ func (JSONMarshaler) Unmarshal(msg *message.Message, v interface{}) (err error)
 }
 
 func (m JSONMarshaler) Name(cmdOrEvent interface{}) string {
-	return ObjectName(cmdOrEvent)
+	if m.GenerateName != nil {
+		return m.GenerateName(cmdOrEvent)
+	}
+
+	return FullyQualifiedStructName(cmdOrEvent)
 }
 
 func (m JSONMarshaler) NameFromMessage(msg *message.Message) string {

components/cqrs/marshaler_protobuf.go

@@ -11,7 +11,8 @@ import (
 )
 
 type ProtobufMarshaler struct {
-	NewUUID func() string
+	NewUUID      func() string
+	GenerateName func(v interface{}) string
 }
 
 type NoProtoMessageError struct {
@@ -61,7 +62,11 @@ func (ProtobufMarshaler) Unmarshal(msg *message.Message, v interface{}) (err err
 }
 
 func (m ProtobufMarshaler) Name(cmdOrEvent interface{}) string {
-	return ObjectName(cmdOrEvent)
+	if m.GenerateName != nil {
+		return m.GenerateName(cmdOrEvent)
+	}
+
+	return FullyQualifiedStructName(cmdOrEvent)
 }
 
 func (m ProtobufMarshaler) NameFromMessage(msg *message.Message) string {

components/cqrs/name.go

@@ -0,0 +1,42 @@
+package cqrs
+
+import (
+	"fmt"
+	"strings"
+)
+
+// FullyQualifiedStructName name returns object name in format [package].[type name].
+// It ignores if the value is a pointer or not.
+func FullyQualifiedStructName(v interface{}) string {
+	s := fmt.Sprintf("%T", v)
+	s = strings.TrimLeft(s, "*")
+
+	return s
+}
+
+// StructName name returns struct name in format [type name].
+// It ignores if the value is a pointer or not.
+func StructName(v interface{}) string {
+	segments := strings.Split(fmt.Sprintf("%T", v), ".")
+
+	return segments[len(segments)-1]
+}
+
+type namedStruct interface {
+	Name() string
+}
+
+// NamedStruct returns the name from a message implementing the following interface:
+// 		type namedStruct interface {
+// 			Name() string
+// 		}
+// It ignores if the value is a pointer or not.
+func NamedStruct(fallback func(v interface{}) string) func(v interface{}) string {
+	return func(v interface{}) string {
+		if v, ok := v.(namedStruct); ok {
+			return v.Name()
+		}
+
+		return fallback(v)
+	}
+}

components/cqrs/name_test.go

@@ -0,0 +1,49 @@
+package cqrs_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/ThreeDotsLabs/watermill/components/cqrs"
+)
+
+func TestFullyQualifiedStructName(t *testing.T) {
+	type Object struct{}
+
+	assert.Equal(t, "cqrs_test.Object", cqrs.FullyQualifiedStructName(Object{}))
+	assert.Equal(t, "cqrs_test.Object", cqrs.FullyQualifiedStructName(&Object{}))
+}
+
+func BenchmarkFullyQualifiedStructName(b *testing.B) {
+	type Object struct{}
+	o := Object{}
+
+	for i := 0; i < b.N; i++ {
+		cqrs.FullyQualifiedStructName(o)
+	}
+}
+
+func TestStructName(t *testing.T) {
+	type Object struct{}
+
+	assert.Equal(t, "Object", cqrs.StructName(Object{}))
+	assert.Equal(t, "Object", cqrs.StructName(&Object{}))
+}
+
+func TestNamedStruct(t *testing.T) {
+	assert.Equal(t, "named object", cqrs.NamedStruct(cqrs.StructName)(namedObject{}))
+	assert.Equal(t, "named object", cqrs.NamedStruct(cqrs.StructName)(&namedObject{}))
+
+	// Test fallback
+	type Object struct{}
+
+	assert.Equal(t, "Object", cqrs.NamedStruct(cqrs.StructName)(Object{}))
+	assert.Equal(t, "Object", cqrs.NamedStruct(cqrs.StructName)(&Object{}))
+}
+
+type namedObject struct{}
+
+func (namedObject) Name() string {
+	return "named object"
+}

components/cqrs/object.go

@@ -1,9 +1,7 @@
 package cqrs
 
 import (
-	"fmt"
 	"reflect"
-	"strings"
 )
 
 func isPointer(v interface{}) error {
@@ -23,12 +21,3 @@ type NonPointerError struct {
 func (e NonPointerError) Error() string {
 	return "non-pointer command: " + e.Type.String() + ", handler.NewCommand() should return pointer to the command"
 }
-
-// ObjectName name returns object name in format [package].[type name].
-// It ignores if the value is a pointer or not.
-func ObjectName(v interface{}) string {
-	s := fmt.Sprintf("%T", v)
-	s = strings.TrimLeft(s, "*")
-
-	return s
-}