fixed sort via pipeline

crud.go

@@ -176,13 +176,15 @@ func (db *MgoDatabase) ReadCollection(results interface{}, filter bson.M, select
 		}
 
 		if len(sort) > 0 {
-			sortM := bson.M{}
+			sortM := bson.D{}
 			for _, s := range sort {
 				if strings.HasPrefix(s, "-") {
 					s = s[1:]
-					sortM[s] = -1
+					sortM = append(sortM, bson.DocElem{Name: s, Value: -1})
+					// sortM[s] = -1
 				} else {
-					sortM[s] = 1
+					sortM = append(sortM, bson.DocElem{Name: s, Value: 1})
+					// sortM[s] = 1
 				}
 			}
 			// spew.Dump(sortM)

mgo.go

@@ -36,8 +36,13 @@ func (c *MgoConnection) Close() {
 }
 
 type MgoSession struct {
-	session *mgo.Session
-	closed  bool
+	connection *MgoConnection
+	session    *mgo.Session
+	closed     bool
+}
+
+func (s *MgoSession) Connection() Connection {
+	return s.connection
 }
 
 func (s *MgoSession) Close() {
@@ -49,7 +54,10 @@ func (s *MgoSession) Close() {
 }
 
 func (c *MgoConnection) NewSession() Session {
-	s := &MgoSession{session: c.connection.Copy()}
+	s := &MgoSession{
+		connection: c,
+		session:    c.connection.Copy(),
+	}
 	runtime.SetFinalizer(s, func(s *MgoSession) {
 		if !s.closed {
 			s.Close()
@@ -68,15 +76,23 @@ func (s *MgoSession) DB(name string) Database {
 }
 
 type MgoCollection struct {
+	database   *MgoDatabase
 	collection *mgo.Collection
 }
 
+func (c *MgoCollection) DB() Database {
+	return c.database
+}
+
 func (db *MgoDatabase) Session() Session {
 	return db.session
 }
 
 func (db *MgoDatabase) C(name string) Collection {
-	return &MgoCollection{collection: db.database.C(name)}
+	return &MgoCollection{
+		database:   db,
+		collection: db.database.C(name),
+	}
 }
 
 func (db *MgoDatabase) Name() string {

setup.go

@@ -9,10 +9,22 @@ import (
 )
 
 // EnsureIndex ensured mongodb index reflecting model struct index tag
-func (db *MgoDatabase) EnsureIndex(m ModelInterface) error {
+func (db *MgoDatabase) EnsureIndex(m ModelInterface, index ...Index) error {
 	colName := GetCollectionName(m)
 	col := db.C(colName)
 
+	if len(index) > 0 {
+		// only ensure given index
+		for _, i := range index {
+			err := col.EnsureIndex(i)
+			if err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+
+	// ensure index by struct fields
 	mType := reflect.TypeOf(m)
 
 	textFields := []string{}

types.go

@@ -16,16 +16,16 @@ type Connection interface {
 }
 
 type Session interface {
+	Connection() Connection
 	Close()
 	DB(name string) Database
 }
 
 type Database interface {
 	Session() Session
-	C(name string) Collection
+	// C(name string) Collection
 	Name() string
-	EnsureIndex(m ModelInterface) error
-	ValidateObject(m ModelInterface, changes bson.M) error
+	EnsureIndex(m ModelInterface, index ...Index) error
 	ReadDocument(m ModelInterface, selector bson.M) error
 	CreateDocument(m ModelInterface) error
 	ReadCollection(results interface{}, filter bson.M, selector bson.M, offset int, limit int, sort []string, pipelineModifier PipelineModifierFunction) error
@@ -37,6 +37,7 @@ type Database interface {
 }
 
 type Collection interface {
+	DB() Database
 	Insert(docs ...interface{}) error
 	UpdateId(id interface{}, update interface{}) error
 	RemoveId(id interface{}) error

validator.go

@@ -6,7 +6,7 @@ import (
 )
 
 // ValidateObject validates object via validator tag and custom method
-func (db *MgoDatabase) ValidateObject(m ModelInterface, changes bson.M) error {
+func ValidateObject(db Database, m ModelInterface, changes bson.M) error {
 	// first validate via struct tag
 	validator := validator.New(&validator.Config{
 		TagName: "validator",