Put project modules under pkg directory

pkg/cgnolink/link/dto.go

@@ -0,0 +1,50 @@
+package link
+
+import (
+	"net/url"
+	"time"
+)
+
+type CreationModel struct {
+	Id          string `json:"id"`
+	Name        string `json:"name"`
+	RedirectURL string `json:"redirectUrl"`
+	Password    string `json:"password"`
+}
+
+type ResourceModel struct {
+	Id           string `json:"id"`
+	Name         string `json:"name"`
+	RedirectURL  string `json:"redirectUrl"`
+	CreationTime int64  `json:"creationTime"`
+}
+
+type UpdateModel struct {
+	Name        string `json:"name,omitempty"`
+	RedirectURL string `json:"redirectUrl,omitempty"`
+	Password    string `json:"password"`
+}
+
+func (m *CreationModel) MapModelToEntity() (*Link, error) {
+	u, err := url.Parse(m.RedirectURL)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Link{
+		Id:           m.Id,
+		Name:         m.Name,
+		RedirectURL:  *u,
+		Password:     m.Password,
+		CreationTime: time.Now().UTC(),
+	}, nil
+}
+
+func MapEntityToModel(entity *Link) ResourceModel {
+	return ResourceModel{
+		Id:           entity.Id,
+		Name:         entity.Name,
+		RedirectURL:  entity.RedirectURL.String(),
+		CreationTime: entity.CreationTime.Unix(),
+	}
+}

pkg/cgnolink/link/entity.go

@@ -0,0 +1,16 @@
+package link
+
+import (
+	"net/url"
+	"time"
+)
+
+type Link struct {
+	Id           string
+	Name         string
+	RedirectURL  url.URL
+	Password     string
+	CreationTime time.Time
+}
+
+type Links = []*Link

pkg/cgnolink/link/handlers.go

@@ -0,0 +1,151 @@
+package link
+
+import (
+	"encoding/json"
+	"github.com/jackc/pgx/v4/pgxpool"
+	"github.com/labstack/echo/v4"
+	"net/http"
+	"net/url"
+	"strconv"
+)
+
+func redirectHandler(ctx echo.Context, serv Service) error {
+	linkId := ctx.Param("id")
+	linkPassword := ctx.QueryParam("password")
+
+	redirectUrl, err := serv.AccessLink(linkId, linkPassword)
+	if err != nil {
+		return err
+	}
+
+	return ctx.Redirect(http.StatusSeeOther, redirectUrl.String())
+}
+
+func creationHandler(ctx echo.Context, serv Service) error {
+	var model CreationModel
+	if err := json.NewDecoder(ctx.Request().Body).Decode(&model); err != nil {
+		return echo.NewHTTPError(http.StatusBadRequest, "Invalid data format.")
+	}
+
+	entity, err := model.MapModelToEntity()
+	if err != nil {
+		return echo.NewHTTPError(http.StatusBadRequest, "Invalid URL.")
+	}
+
+	if err = serv.Create(entity); err != nil {
+		return err
+	}
+
+	return ctx.NoContent(http.StatusCreated)
+}
+
+func retrievalByIdHandler(ctx echo.Context, serv Service) error {
+	linkId := ctx.Param("id")
+
+	l, err := serv.GetById(linkId)
+	if err != nil {
+		return err
+	}
+
+	return ctx.JSON(http.StatusOK, MapEntityToModel(l))
+}
+
+func allRetrievalHandler(ctx echo.Context, serv Service) error {
+	limit := 20
+	if v := ctx.QueryParam("limit"); v != "" {
+		num, err := strconv.Atoi(v)
+		if err != nil || num < 0 {
+			return echo.NewHTTPError(http.StatusBadRequest, "Invalid limit value.")
+		}
+
+		limit = num
+	}
+
+	offset := 0
+	if v := ctx.QueryParam("offset"); v != "" {
+		num, err := strconv.Atoi(v)
+		if err != nil || num < 0 {
+			return echo.NewHTTPError(http.StatusBadRequest, "Invalid offset value.")
+		}
+
+		offset = num
+	}
+
+	links, err := serv.GetAll(limit, offset)
+	if err != nil {
+		return err
+	}
+
+	models := make([]ResourceModel, len(links))
+	for i, v := range links {
+		models[i] = MapEntityToModel(v)
+	}
+
+	return ctx.JSON(http.StatusOK, models)
+}
+
+func updateHandler(ctx echo.Context, serv Service) error {
+	linkId := ctx.Param("id")
+
+	var model UpdateModel
+	if err := json.NewDecoder(ctx.Request().Body).Decode(&model); err != nil {
+		return echo.NewHTTPError(http.StatusBadRequest, "Invalid data format.")
+	}
+
+	var parsedUrl *url.URL
+	parsedUrl, err := url.Parse(model.RedirectURL)
+	if err != nil {
+		return echo.NewHTTPError(http.StatusBadRequest, "Invalid URL value.")
+	}
+
+	if err := serv.UpdateById(linkId, struct {
+		Name        string
+		Password    string
+		RedirectURL *url.URL
+	}{Name: model.Name, Password: model.Password, RedirectURL: parsedUrl}); err != nil {
+		return err
+	}
+
+	return ctx.NoContent(http.StatusOK)
+}
+
+func removalHandler(ctx echo.Context, serv Service) error {
+	linkId := ctx.Param("id")
+
+	if err := serv.DeleteById(linkId); err != nil {
+		return err
+	}
+
+	return ctx.NoContent(http.StatusNoContent)
+}
+
+func AddHandlers(server *echo.Echo, pool *pgxpool.Pool) {
+	serv := NewService(NewRepository(pool))
+
+	linksGroup := server.Group("/links")
+	exactLinkGroup := linksGroup.Group("/:id")
+
+	linksGroup.POST("", func(ctx echo.Context) error {
+		return creationHandler(ctx, serv)
+	})
+
+	linksGroup.GET("", func(ctx echo.Context) error {
+		return allRetrievalHandler(ctx, serv)
+	})
+
+	exactLinkGroup.GET("", func(ctx echo.Context) error {
+		return retrievalByIdHandler(ctx, serv)
+	})
+
+	exactLinkGroup.PATCH("", func(ctx echo.Context) error {
+		return updateHandler(ctx, serv)
+	})
+
+	exactLinkGroup.DELETE("", func(ctx echo.Context) error {
+		return removalHandler(ctx, serv)
+	})
+
+	server.GET("/:id", func(ctx echo.Context) error {
+		return redirectHandler(ctx, serv)
+	})
+}

pkg/cgnolink/link/repository.go

@@ -0,0 +1,182 @@
+package link
+
+import (
+	"cgnolink/pkg/cgnolink/database"
+	"context"
+	"errors"
+	"github.com/jackc/pgtype"
+	"github.com/jackc/pgx/v4"
+	"github.com/jackc/pgx/v4/pgxpool"
+	"net/url"
+	"time"
+)
+
+const defaultContextTimeout = 10 * time.Second
+
+type Repository interface {
+	Save(link *Link) error
+	FindById(id string) (*Link, error)
+	GetAll(limit int, offset int) (Links, error)
+	Update(link *Link) error
+	DeleteById(id string) error
+}
+
+type PgRepository struct {
+	pool *pgxpool.Pool
+}
+
+func NewRepository(pool *pgxpool.Pool) Repository {
+	return &PgRepository{pool: pool}
+}
+
+func (r *PgRepository) Save(link *Link) error {
+	ctx, cancel := context.WithTimeout(context.Background(), defaultContextTimeout)
+	defer cancel()
+
+	sql := `
+		INSERT INTO links (id, name, redirect_url, password, creation_time) 
+		VALUES ($1, $2, $3, $4, $5::timestamp)
+	`
+
+	database.LogPoolState(r.pool, "Saving link")
+	_, err := r.pool.Exec(ctx, sql, link.Id, link.Name, link.RedirectURL.String(), link.Password, link.CreationTime.Format("2006-01-02 15:04:05"))
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (r *PgRepository) FindById(id string) (*Link, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), defaultContextTimeout)
+	defer cancel()
+
+	sql := `
+		SELECT id, name, redirect_url, password, creation_time
+		FROM links
+		WHERE id = $1
+	`
+
+	database.LogPoolState(r.pool, "Finding link by ID")
+	entity, err := mapRowToEntity(r.pool.QueryRow(ctx, sql, id))
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return nil, nil
+		} else {
+			return nil, err
+		}
+	}
+
+	return entity, nil
+}
+
+func (r *PgRepository) GetAll(limit int, offset int) (Links, error) {
+	if limit < 0 {
+		return nil, errors.New("limit can't be negative")
+	}
+	if offset < 0 {
+		return nil, errors.New("offset can't be negative")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultContextTimeout)
+	defer cancel()
+
+	sql := `
+		SELECT id, name, redirect_url, password, creation_time
+		FROM links
+		LIMIT $1
+		OFFSET $2
+	`
+
+	database.LogPoolState(r.pool, "Getting all links")
+	rows, err := r.pool.Query(ctx, sql, limit, offset)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	links := make(Links, 0)
+	for rows.Next() {
+		link, err := mapRowToEntity(rows)
+		if err != nil {
+			return nil, err
+		}
+
+		links = append(links, link)
+	}
+
+	if err = rows.Err(); err != nil {
+		return nil, err
+	}
+
+	return links, nil
+}
+
+func (r *PgRepository) Update(link *Link) error {
+	if link.Id == "" {
+		return errors.New("link ID must not be empty")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultContextTimeout)
+	defer cancel()
+
+	sql := `
+		UPDATE links
+		SET name = $1, redirect_url = $2, password = $3
+		WHERE id = $4
+	`
+
+	database.LogPoolState(r.pool, "Updating link")
+	_, err := r.pool.Exec(ctx, sql, link.Name, link.RedirectURL.String(), link.Password, link.Id)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (r *PgRepository) DeleteById(id string) error {
+	ctx, cancel := context.WithTimeout(context.Background(), defaultContextTimeout)
+	defer cancel()
+
+	sql := `
+		DELETE FROM links WHERE id = $1
+	`
+
+	database.LogPoolState(r.pool, "Deleting link")
+	_, err := r.pool.Exec(ctx, sql, id)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func mapRowToEntity(r interface{}) (*Link, error) {
+	var entity Link
+	var urlStr string
+	var t pgtype.Timestamp
+
+	switch v := r.(type) {
+	case pgx.Row:
+		if err := v.Scan(&entity.Id, &entity.Name, &urlStr, &entity.Password, &t); err != nil {
+			return nil, err
+		}
+	case pgx.Rows:
+		if err := v.Scan(&entity.Id, &entity.Name, &urlStr, &entity.Password, &t); err != nil {
+			return nil, err
+		}
+	default:
+		return nil, errors.New("unsupported type")
+	}
+
+	u, err := url.Parse(urlStr)
+	if err != nil {
+		return nil, err
+	}
+
+	entity.RedirectURL = *u
+	entity.CreationTime = t.Time
+
+	return &entity, nil
+}

pkg/cgnolink/link/service.go

@@ -0,0 +1,171 @@
+package link
+
+import (
+	apperrors "cgnolink/pkg/cgnolink/errors"
+	"github.com/patrickmn/go-cache"
+	"golang.org/x/crypto/bcrypt"
+	"net/url"
+)
+
+var linkNotFoundError = apperrors.NotFoundError{Message: "Link with given ID was not found."}
+
+type Service interface {
+	Create(link *Link) error
+	GetById(id string) (*Link, error)
+	AccessLink(id string, password string) (*url.URL, error)
+	GetAll(limit int, offset int) (Links, error)
+	UpdateById(
+		id string,
+		data struct {
+			Name        string
+			Password    string
+			RedirectURL *url.URL
+		},
+	) error
+	DeleteById(id string) error
+}
+
+type PgService struct {
+	rep   Repository
+	cache *cache.Cache
+}
+
+func (service *PgService) AccessLink(id string, password string) (*url.URL, error) {
+	link, err := service.GetById(id)
+	if err != nil {
+		return nil, err
+	}
+
+	if link.Password != "" {
+		if password == "" || bcrypt.CompareHashAndPassword([]byte(link.Password), []byte(password)) != nil {
+			return nil, linkNotFoundError
+		}
+	}
+
+	return &link.RedirectURL, nil
+}
+
+func NewService(rep Repository) Service {
+	return &PgService{
+		rep:   rep,
+		cache: cache.New(cache.NoExpiration, 0),
+	}
+}
+
+func (service *PgService) Create(link *Link) error {
+	existingLink, err := service.rep.FindById(link.Id)
+	if err != nil {
+		return apperrors.UnknownError{Err: err}
+	}
+
+	if existingLink != nil {
+		return apperrors.AlreadyExistsError{Message: "Link with given ID already exists."}
+	}
+
+	if link.Password != "" {
+		hashedPassword, err := HashPassword(link.Password)
+		if err != nil {
+			return err
+		}
+
+		link.Password = hashedPassword
+	}
+
+	if err = service.rep.Save(link); err != nil {
+		return apperrors.UnknownError{Err: err}
+	}
+
+	return nil
+}
+
+func (service *PgService) GetById(id string) (*Link, error) {
+	if v, found := service.cache.Get(id); found {
+		if link, ok := v.(*Link); ok {
+			return link, nil
+		}
+	}
+
+	link, err := service.rep.FindById(id)
+	if err != nil {
+		return nil, apperrors.UnknownError{Err: err}
+	}
+
+	if link == nil {
+		return nil, linkNotFoundError
+	}
+
+	service.cache.Set(id, link, cache.DefaultExpiration)
+
+	return link, nil
+}
+
+func (service *PgService) GetAll(limit int, offset int) (Links, error) {
+	links, err := service.rep.GetAll(limit, offset)
+	if err != nil {
+		return nil, apperrors.UnknownError{Err: err}
+	}
+
+	return links, nil
+}
+
+func (service *PgService) UpdateById(
+	id string,
+	data struct {
+		Name        string
+		Password    string
+		RedirectURL *url.URL
+	},
+) error {
+	link, err := service.GetById(id)
+	if err != nil {
+		return err
+	}
+
+	hasChanges := false
+	switch {
+	case data.Name != "":
+		link.Name = data.Name
+
+		hasChanges = true
+	case data.RedirectURL != nil:
+		link.RedirectURL = *data.RedirectURL
+
+		hasChanges = true
+	case data.Password != "":
+		hashedPw, err := HashPassword(data.Password)
+		if err != nil {
+			return err
+		}
+
+		link.Password = hashedPw
+
+		hasChanges = true
+	}
+
+	if hasChanges {
+		if err := service.rep.Update(link); err != nil {
+			return apperrors.UnknownError{Err: err}
+		}
+		service.cache.Delete(link.Id)
+	}
+
+	return nil
+}
+
+func (service *PgService) DeleteById(id string) error {
+	if err := service.rep.DeleteById(id); err != nil {
+		return apperrors.UnknownError{Err: err}
+	}
+	service.cache.Delete(id)
+
+	return nil
+}
+
+func HashPassword(password string) (string, error) {
+	hashedPw, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
+	if err != nil {
+		return "", apperrors.UnknownError{Err: err}
+	}
+
+	return string(hashedPw), nil
+}