Add JSON Marshalling support to device and entity

spine/device.go

@@ -1,6 +1,10 @@
 package spine
 
-import "github.com/enbility/spine-go/model"
+import (
+	"encoding/json"
+
+	"github.com/enbility/spine-go/model"
+)
 
 type Device struct {
 	address    *model.AddressDeviceType
@@ -33,6 +37,26 @@ func (r *Device) Address() *model.AddressDeviceType {
 	return r.address
 }
 
+// Add support for JSON Marshalling
+//
+// Instances of EntityInterface are used as arguments and return values in various API calls,
+// therefor it is helpfull to be able to marshal them to JSON and thus make the API calls
+// usable with various communication interfaces
+func (r *Device) MarshalJSON() ([]byte, error) {
+	var tempAddress string
+
+	if r.address != nil {
+		tempAddress = string(*r.address)
+	}
+
+	bytes, err := json.Marshal(tempAddress)
+	if err != nil {
+		return nil, err
+	}
+
+	return bytes, nil
+}
+
 func (r *Device) DeviceType() *model.DeviceTypeType {
 	return r.dType
 }

spine/device_test.go

@@ -0,0 +1,35 @@
+package spine
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/enbility/spine-go/model"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/suite"
+)
+
+func TestDeviceSuite(t *testing.T) {
+	suite.Run(t, new(DeviceTestSuite))
+}
+
+type DeviceTestSuite struct {
+	suite.Suite
+}
+
+func (s *DeviceTestSuite) Test_Device() {
+	deviceAddress := model.AddressDeviceType("test")
+	device := NewDevice(&deviceAddress, nil, nil)
+
+	value, err := json.Marshal(device)
+	assert.Nil(s.T(), err)
+	assert.NotNil(s.T(), value)
+	assert.Equal(s.T(), `"test"`, string(value))
+
+	device = NewDevice(nil, nil, nil)
+
+	value, err = json.Marshal(device)
+	assert.Nil(s.T(), err)
+	assert.NotNil(s.T(), value)
+	assert.Equal(s.T(), `""`, string(value))
+}

spine/entity.go

@@ -1,6 +1,7 @@
 package spine
 
 import (
+	"encoding/json"
 	"sync"
 
 	"github.com/ahmetb/go-linq/v3"
@@ -32,7 +33,7 @@ func NewEntity(eType model.EntityTypeType, deviceAddress *model.AddressDeviceTyp
 			Entity: entityAddress,
 		},
 	}
-	if entityAddress[0] == 0 {
+	if entityAddress != nil && entityAddress[0] == 0 {
 		// Entity 0 Feature addresses start with 0
 		entity.fIdGenerator = newFeatureIdGenerator(0)
 	} else {
@@ -47,6 +48,33 @@ func (r *Entity) Address() *model.EntityAddressType {
 	return r.address
 }
 
+// Add support for JSON Marshalling
+//
+// Instances of EntityInterface are used as arguments and return values in various API calls,
+// therefor it is helpfull to be able to marshal them to JSON and thus make the API calls
+// usable with various communication interfaces
+func (r *Entity) MarshalJSON() ([]byte, error) {
+	// we do not want to omit address fields, if they are nil
+	// and field names should not be lowercased
+	type tempAddressType struct {
+		Device model.AddressDeviceType
+		Entity []model.AddressEntityType
+	}
+	var tempAddress tempAddressType
+
+	if r.address.Device != nil {
+		tempAddress.Device = *r.address.Device
+	}
+	tempAddress.Entity = r.address.Entity
+
+	bytes, err := json.Marshal(tempAddress)
+	if err != nil {
+		return nil, err
+	}
+
+	return bytes, nil
+}
+
 func (r *Entity) EntityType() model.EntityTypeType {
 	return r.eType
 }

spine/entity_test.go

@@ -0,0 +1,42 @@
+package spine
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/enbility/spine-go/model"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/suite"
+)
+
+func TestEntitySuite(t *testing.T) {
+	suite.Run(t, new(EntityTestSuite))
+}
+
+type EntityTestSuite struct {
+	suite.Suite
+}
+
+func (s *EntityTestSuite) Test_Entity() {
+	deviceAddress := model.AddressDeviceType("test")
+	entity := NewEntity(model.EntityTypeTypeCEM, &deviceAddress, NewAddressEntityType([]uint{1, 1}))
+
+	value, err := json.Marshal(entity)
+	assert.Nil(s.T(), err)
+	assert.NotNil(s.T(), value)
+	assert.Equal(s.T(), `{"Device":"test","Entity":[1,1]}`, string(value))
+
+	entity = NewEntity(model.EntityTypeTypeCEM, &deviceAddress, nil)
+
+	value, err = json.Marshal(entity)
+	assert.Nil(s.T(), err)
+	assert.NotNil(s.T(), value)
+	assert.Equal(s.T(), `{"Device":"test","Entity":null}`, string(value))
+
+	entity = NewEntity(model.EntityTypeTypeCEM, nil, nil)
+
+	value, err = json.Marshal(entity)
+	assert.Nil(s.T(), err)
+	assert.NotNil(s.T(), value)
+	assert.Equal(s.T(), `{"Device":"","Entity":null}`, string(value))
+}