add author books relations and basic structure

Author: eldimious

data/authors/mapper.go

@@ -0,0 +1,24 @@
+package authors
+
+import (
+	domain "github.com/eldimious/golang-api-showcase/domain/authors"
+)
+
+func toDBModel(entity *domain.Author) *Author {
+	return &Author{
+		ID:      entity.ID,
+		Name:    entity.Name,
+		Surname: entity.Surname,
+	}
+}
+
+func toDomainModel(entity *Author) *domain.Author {
+	return &domain.Author{
+		ID:        entity.ID,
+		Name:      entity.Name,
+		Surname:   entity.Surname,
+		CreatedAt: entity.CreatedAt,
+		UpdatedAt: entity.UpdatedAt,
+		DeletedAt: entity.DeletedAt,
+	}
+}

data/authors/schema.go

@@ -0,0 +1,15 @@
+package authors
+
+import (
+	"time"
+)
+
+// struct defines the database model for a Author.
+type Author struct {
+	ID        int `gorm:"primary_key;type:int;"`
+	CreatedAt time.Time
+	UpdatedAt time.Time
+	DeletedAt *time.Time
+	Name      string
+	Surname   string
+}

data/authors/store.go

@@ -0,0 +1,78 @@
+package authors
+
+import (
+	"github.com/jinzhu/gorm"
+	"github.com/pkg/errors"
+
+	domain "github.com/eldimious/golang-api-showcase/domain/authors"
+	booksDomain "github.com/eldimious/golang-api-showcase/domain/books"
+	domainErrors "github.com/eldimious/golang-api-showcase/domain/errors"
+)
+
+const (
+	createError = "Error in creating new author"
+	readError   = "Error in finding author in the database"
+	listError   = "Error in getting authors from the database"
+)
+
+// Store struct manages interactions with authors store
+type Store struct {
+	db        *gorm.DB
+	booksRepo booksDomain.BookRepository
+}
+
+// New creates a new Store struct
+func New(db *gorm.DB, booksRepo booksDomain.BookRepository) *Store {
+	db.AutoMigrate(&Author{})
+
+	return &Store{
+		db:        db,
+		booksRepo: booksRepo,
+	}
+}
+
+func (s *Store) CreateAuthor(author *domain.Author) (*domain.Author, error) {
+	entity := toDBModel(author)
+
+	if err := s.db.Create(entity).Error; err != nil {
+		appErr := domainErrors.NewAppError(errors.Wrap(err, createError), domainErrors.RepositoryError)
+		return nil, appErr
+	}
+
+	return toDomainModel(entity), nil
+}
+
+func (s *Store) ReadAuthor(id int) (*domain.Author, error) {
+	result := &Author{}
+
+	query := s.db.Where("id = ?", id).First(result)
+
+	if query.RecordNotFound() {
+		appErr := domainErrors.NewAppErrorWithType(domainErrors.NotFound)
+		return nil, appErr
+	}
+
+	if err := query.Error; err != nil {
+		appErr := domainErrors.NewAppError(errors.Wrap(err, readError), domainErrors.RepositoryError)
+		return nil, appErr
+	}
+
+	return toDomainModel(result), nil
+}
+
+func (s *Store) ListAuthors() ([]domain.Author, error) {
+	var results []Author
+
+	if err := s.db.Find(&results).Error; err != nil {
+		appErr := domainErrors.NewAppError(errors.Wrap(err, listError), domainErrors.RepositoryError)
+		return nil, appErr
+	}
+
+	var authors = make([]domain.Author, len(results))
+
+	for i, element := range results {
+		authors[i] = *toDomainModel(&element)
+	}
+
+	return authors, nil
+}

data/books/mapper.go

@@ -0,0 +1,25 @@
+package books
+
+import (
+	domain "github.com/eldimious/golang-api-showcase/domain/books"
+)
+
+func toDBModel(entity *domain.Book) *Book {
+	return &Book{
+		ID:        entity.ID,
+		Name:      entity.Name,
+		Publisher: entity.Publisher,
+		AuthorID:  entity.AuthorID,
+	}
+}
+
+func toDomainModel(entity *Book) *domain.Book {
+	return &domain.Book{
+		ID:        entity.ID,
+		Name:      entity.Name,
+		Publisher: entity.Publisher,
+		CreatedAt: entity.CreatedAt,
+		UpdatedAt: entity.UpdatedAt,
+		DeletedAt: entity.DeletedAt,
+	}
+}

data/books/schema.go

@@ -0,0 +1,19 @@
+package books
+
+import (
+	"time"
+
+	authorSchema "github.com/eldimious/golang-api-showcase/data/authors"
+)
+
+// struct defines the database model for a Author.
+type Book struct {
+	ID        int `gorm:"primary_key;type:int;"`
+	CreatedAt time.Time
+	UpdatedAt time.Time
+	DeletedAt *time.Time
+	Name      string
+	Publisher string
+	Author    authorSchema.Author
+	AuthorID  int `gorm:"type:int;"`
+}

data/books/store.go

@@ -0,0 +1,84 @@
+package books
+
+import (
+	"github.com/jinzhu/gorm"
+	"github.com/pkg/errors"
+
+	authorSchema "github.com/eldimious/golang-api-showcase/data/authors"
+	domain "github.com/eldimious/golang-api-showcase/domain/books"
+	domainErrors "github.com/eldimious/golang-api-showcase/domain/errors"
+)
+
+const (
+	createError = "Error in creating new book"
+	readError   = "Error in finding book in the database"
+	listError   = "Error in getting books from the database"
+)
+
+// Store struct manages interactions with books store
+type Store struct {
+	db *gorm.DB
+}
+
+// New creates a new Store struct
+func New(db *gorm.DB) *Store {
+	db.AutoMigrate(&Book{})
+
+	return &Store{
+		db: db,
+	}
+}
+
+// AddAuthorFKConstraint creates a foreign key constraint for the author ID field
+func (s *Store) AddAuthorFKConstraint() {
+	s.db.Model(&Book{}).AddForeignKey("author_id", "authors(id)", "CASCADE", "CASCADE")
+}
+
+func (s *Store) CreateBook(book *domain.Book) (*domain.Book, error) {
+	entity := toDBModel(book)
+
+	if err := s.db.Create(entity).Error; err != nil {
+		appErr := domainErrors.NewAppError(errors.Wrap(err, createError), domainErrors.RepositoryError)
+		return nil, appErr
+	}
+
+	return toDomainModel(entity), nil
+}
+
+func (s *Store) ReadBook(id int) (*domain.Book, error) {
+	result := &Book{}
+
+	query := s.db.Where("id = ?", id).First(result)
+
+	if query.RecordNotFound() {
+		appErr := domainErrors.NewAppErrorWithType(domainErrors.NotFound)
+		return nil, appErr
+	}
+
+	if err := query.Error; err != nil {
+		appErr := domainErrors.NewAppError(errors.Wrap(err, readError), domainErrors.RepositoryError)
+		return nil, appErr
+	}
+
+	return toDomainModel(result), nil
+}
+
+func (s *Store) ListBooks(authorID int) ([]domain.Book, error) {
+	var results []Book
+	author := &authorSchema.Author{
+		ID: authorID,
+	}
+
+	if err := s.db.Model(&author).Related(&results).Error; err != nil {
+		appErr := domainErrors.NewAppError(errors.Wrap(err, listError), domainErrors.RepositoryError)
+		return nil, appErr
+	}
+
+	var books = make([]domain.Book, len(results))
+
+	for i, element := range results {
+		books[i] = *toDomainModel(&element)
+	}
+
+	return books, nil
+}

data/database/postgres.go

@@ -8,8 +8,8 @@ import (
 	_ "github.com/jinzhu/gorm/dialects/postgres" // Import GORM postgres dialect for its side effects, according to GORM docs.
 )
 
-// Open creates a database handle from a connection string.
-func Open(configuration *config.Postgres) (*gorm.DB, error) {
+// Connect to a database handle from a connection string.
+func Connect(configuration *config.Postgres) (*gorm.DB, error) {
 	connStr := fmt.Sprintf("host=%s port=%s dbname=%s user=%s password=%s sslmode=disable", configuration.Host, configuration.Port, configuration.DB, configuration.User, configuration.Password)
 	db, err := gorm.Open("postgres", connStr)
 

domain/authors/author.go

@@ -0,0 +1,15 @@
+package authors
+
+import (
+	"time"
+)
+
+// Author struct contains information an author.
+type Author struct {
+	ID        int
+	Name      string
+	Surname   string
+	CreatedAt time.Time
+	UpdatedAt time.Time
+	DeletedAt *time.Time
+}

domain/authors/repository.go

@@ -0,0 +1,8 @@
+package authors
+
+// AuthorRepository provides an abstraction on top of the author data source
+type AuthorRepository interface {
+	CreateAuthor(*Author) (*Author, error)
+	ReadAuthor(int) (*Author, error)
+	ListAuthors() ([]Author, error)
+}

domain/authors/service.go

@@ -0,0 +1,30 @@
+package authors
+
+// AuthorService defines author service behavior.
+type AuthorService interface {
+	CreateAuthor(*Author) (*Author, error)
+	ReadAuthor(id int) (*Author, error)
+	ListAuthors() ([]Author, error)
+}
+
+// Service struct handles author business logic tasks.
+type Service struct {
+	repository AuthorRepository
+}
+
+func (svc *Service) CreateAuthor(author *Author) (*Author, error) {
+	return svc.repository.CreateAuthor(author)
+}
+
+func (svc *Service) ReadAuthor(id int) (*Author, error) {
+	return svc.repository.ReadAuthor(id)
+}
+
+func (svc *Service) ListAuthors() ([]Author, error) {
+	return svc.repository.ListAuthors()
+}
+
+// NewService creates a new service struct
+func NewService(repository AuthorRepository) *Service {
+	return &Service{repository: repository}
+}