Pagination and ordering

app/main.go

@@ -72,7 +72,7 @@ func doList(db *gorm.DB) {
 		Alive: &TRUE,
 	}
 
-	certs, err := repo.List(filter)
+	certs, err := repo.List(filter, nil, nil)
 	if err != nil {
 		panic(err)
 	}

app/repository/method_list.go

@@ -1,12 +1,30 @@
 package repository
 
 import (
+	"fmt"
 	"repo-pattern/app/repository/smartfilter"
 
 	"gorm.io/gorm"
 	"gorm.io/gorm/schema"
 )
 
+type Pagination struct {
+	Offset int
+	Limit  int
+}
+
+type OrderDirection string
+
+const (
+	OrderASC  OrderDirection = "ASC"
+	OrderDESC OrderDirection = "DESC"
+)
+
+type Order struct {
+	Field     string
+	Direction OrderDirection
+}
+
 type ListMethod[T schema.Tabler] struct {
 	DbConn *gorm.DB
 }
@@ -15,7 +33,36 @@ func (m *ListMethod[T]) Init(dbConn *gorm.DB) {
 	m.DbConn = dbConn
 }
 
-func (m ListMethod[T]) List(filter interface{}) (*[]T, error) {
+func applyOrdering(query *gorm.DB, ordering *[]Order) *gorm.DB {
+	if ordering == nil || len(*ordering) == 0 {
+		return query
+	}
+
+	for _, order := range *ordering {
+		if order.Direction == OrderASC {
+			query = query.Order(order.Field)
+		} else {
+			query = query.Order(fmt.Sprintf("%s %s", order.Field, order.Direction))
+		}
+	}
+	return query
+}
+
+func applyPagination(query *gorm.DB, pagination *Pagination) *gorm.DB {
+	if pagination == nil {
+		return query
+	}
+
+	if pagination.Limit != 0 {
+		query = query.Limit(pagination.Limit)
+	}
+	if pagination.Offset != 0 {
+		query = query.Offset(pagination.Offset)
+	}
+	return query
+}
+
+func (m ListMethod[T]) List(filter interface{}, ordering *[]Order, pagination *Pagination) (*[]T, error) {
 	var (
 		model  T
 		models []T
@@ -26,6 +73,9 @@ func (m ListMethod[T]) List(filter interface{}) (*[]T, error) {
 		return nil, err
 	}
 
+	query = applyOrdering(query, ordering)
+	query = applyPagination(query, pagination)
+
 	query.Find(&models)
 	return &models, nil
 }

app/repository/repository_test.go

@@ -2,6 +2,7 @@ package repository
 
 import (
 	"database/sql"
+	"fmt"
 	"log"
 	"regexp"
 	"testing"
@@ -46,8 +47,113 @@ type MyModelFilter struct {
 	Count *int    `filterfield:"field=count,operator=GT"`
 }
 
-func TestRepository(t *testing.T) {
+func TestListMethod(t *testing.T) {
-	t.Run("List with simple filter", func(t *testing.T) {
+	t.Run("With ordering", func(t *testing.T) {
+		sqldb, db, mock := NewMockDB()
+		defer sqldb.Close()
+
+		repo := RepoBase[MyModel]{}
+		repo.Init(db)
+
+		filter := MyModelFilter{}
+		ordering := []Order{
+			{
+				Field:     "id",
+				Direction: OrderASC,
+			},
+			{
+				Field:     "count",
+				Direction: OrderDESC,
+			},
+		}
+
+		sql := "SELECT * FROM my_models ORDER BY id,count DESC"
+		mock.ExpectQuery(fmt.Sprintf("^%s$", regexp.QuoteMeta(sql)))
+
+		_, err := repo.List(filter, &ordering, nil)
+		assert.Nil(t, err)
+
+		if err := mock.ExpectationsWereMet(); err != nil {
+			t.Errorf("there were unfulfilled expectations: %s", err)
+		}
+	})
+
+	t.Run("With limit", func(t *testing.T) {
+		sqldb, db, mock := NewMockDB()
+		defer sqldb.Close()
+
+		repo := RepoBase[MyModel]{}
+		repo.Init(db)
+
+		filter := MyModelFilter{}
+		pagination := Pagination{
+			Limit:  111,
+			Offset: 0,
+		}
+
+		sql := "SELECT * FROM my_models LIMIT $1"
+		mock.ExpectQuery(fmt.Sprintf("^%s$", regexp.QuoteMeta(sql))).
+			WithArgs(pagination.Limit)
+
+		_, err := repo.List(filter, nil, &pagination)
+		assert.Nil(t, err)
+
+		if err := mock.ExpectationsWereMet(); err != nil {
+			t.Errorf("there were unfulfilled expectations: %s", err)
+		}
+	})
+
+	t.Run("With offset", func(t *testing.T) {
+		sqldb, db, mock := NewMockDB()
+		defer sqldb.Close()
+
+		repo := RepoBase[MyModel]{}
+		repo.Init(db)
+
+		filter := MyModelFilter{}
+		pagination := Pagination{
+			Limit:  0,
+			Offset: 222,
+		}
+
+		sql := "SELECT * FROM my_models OFFSET $1"
+		mock.ExpectQuery(fmt.Sprintf("^%s$", regexp.QuoteMeta(sql))).
+			WithArgs(pagination.Offset)
+
+		_, err := repo.List(filter, nil, &pagination)
+		assert.Nil(t, err)
+
+		if err := mock.ExpectationsWereMet(); err != nil {
+			t.Errorf("there were unfulfilled expectations: %s", err)
+		}
+	})
+
+	t.Run("With limit and offset", func(t *testing.T) {
+		sqldb, db, mock := NewMockDB()
+		defer sqldb.Close()
+
+		repo := RepoBase[MyModel]{}
+		repo.Init(db)
+
+		filter := MyModelFilter{}
+		pagination := Pagination{
+			Limit:  111,
+			Offset: 222,
+		}
+
+		sql := "SELECT * FROM my_models LIMIT $1 OFFSET $2"
+		mock.ExpectQuery(fmt.Sprintf("^%s$", regexp.QuoteMeta(sql))).
+			WithArgs(pagination.Limit, pagination.Offset)
+
+		_, err := repo.List(filter, nil, &pagination)
+		assert.Nil(t, err)
+
+		if err := mock.ExpectationsWereMet(); err != nil {
+			t.Errorf("there were unfulfilled expectations: %s", err)
+		}
+	})
+
+	t.Run("Simple filter", func(t *testing.T) {
 		sqldb, db, mock := NewMockDB()
 		defer sqldb.Close()
 
@@ -60,9 +166,10 @@ func TestRepository(t *testing.T) {
 		}
 
 		sql := "SELECT * FROM my_models WHERE my_models.id = $1"
-		mock.ExpectQuery(regexp.QuoteMeta(sql)).WithArgs(id)
+		mock.ExpectQuery(fmt.Sprintf("^%s$", regexp.QuoteMeta(sql))).
+			WithArgs(id)
 
-		_, err := repo.List(filter)
+		_, err := repo.List(filter, nil, nil)
 		assert.Nil(t, err)
 
 		if err := mock.ExpectationsWereMet(); err != nil {
@@ -70,7 +177,7 @@ func TestRepository(t *testing.T) {
 		}
 	})
 
-	t.Run("List with multiple filter values", func(t *testing.T) {
+	t.Run("Multiple filter values", func(t *testing.T) {
 		sqldb, db, mock := NewMockDB()
 		defer sqldb.Close()
 
@@ -87,9 +194,42 @@ func TestRepository(t *testing.T) {
 		}
 
 		sql := "SELECT * FROM my_models WHERE my_models.id = $1 AND my_models.value = $2 AND my_models.count > $3"
-		mock.ExpectQuery(regexp.QuoteMeta(sql)).WithArgs(id, value, count)
+		mock.ExpectQuery(fmt.Sprintf("^%s$", regexp.QuoteMeta(sql))).
+			WithArgs(id, value, count)
 
-		_, err := repo.List(filter)
+		_, err := repo.List(filter, nil, nil)
+		assert.Nil(t, err)
+
+		if err := mock.ExpectationsWereMet(); err != nil {
+			t.Errorf("there were unfulfilled expectations: %s", err)
+		}
+	})
+
+	t.Run("Multiple filter values and pagination", func(t *testing.T) {
+		sqldb, db, mock := NewMockDB()
+		defer sqldb.Close()
+
+		repo := RepoBase[MyModel]{}
+		repo.Init(db)
+
+		id := 123
+		count := 456
+		value := "some value"
+		filter := MyModelFilter{
+			Id:    &id,
+			Value: &value,
+			Count: &count,
+		}
+		pagination := Pagination{
+			Offset: 111,
+			Limit:  222,
+		}
+
+		sql := "SELECT * FROM my_models WHERE my_models.id = $1 AND my_models.value = $2 AND my_models.count > $3 LIMIT $4 OFFSET $5"
+		mock.ExpectQuery(fmt.Sprintf("^%s$", regexp.QuoteMeta(sql))).
+			WithArgs(id, value, count, pagination.Limit, pagination.Offset)
+
+		_, err := repo.List(filter, nil, &pagination)
 		assert.Nil(t, err)
 
 		if err := mock.ExpectationsWereMet(); err != nil {