Add endpoints for retrieving link/links data

link/handlers.go

@@ -5,6 +5,7 @@ import (
 	"github.com/jackc/pgx/v4/pgxpool"
 	"github.com/labstack/echo/v4"
 	"net/http"
+	"strconv"
 )
 
 func redirectHandler(c echo.Context, pool *pgxpool.Pool) error {
@@ -53,6 +54,59 @@ func creationHandler(c echo.Context, pool *pgxpool.Pool) error {
 	return c.NoContent(http.StatusCreated)
 }
 
+func retrievalByIdHandler(c echo.Context, pool *pgxpool.Pool) error {
+	linkId := c.Param("id")
+
+	rep := PgRepository{pool: pool}
+
+	link, err := rep.FindById(linkId)
+	if err != nil {
+		return echo.NewHTTPError(http.StatusInternalServerError)
+	}
+
+	if link == nil {
+		return echo.NewHTTPError(http.StatusNotFound, "Link with given ID was not found.")
+	}
+
+	return c.JSON(http.StatusOK, MapEntityToModel(link))
+}
+
+func allRetrievalHandler(c echo.Context, pool *pgxpool.Pool) error {
+	limit := 20
+	if v := c.QueryParam("limit"); v != "" {
+		num, err := strconv.Atoi(v)
+		if err != nil {
+			return echo.NewHTTPError(http.StatusBadRequest, "Invalid limit value.")
+		}
+
+		limit = num
+	}
+
+	offset := 0
+	if v := c.QueryParam("offset"); v != "" {
+		num, err := strconv.Atoi(v)
+		if err != nil {
+			return echo.NewHTTPError(http.StatusBadRequest, "Invalid offset value.")
+		}
+
+		offset = num
+	}
+
+	rep := PgRepository{pool: pool}
+
+	links, err := rep.FindAll(limit, offset)
+	if err != nil {
+		return echo.NewHTTPError(http.StatusInternalServerError)
+	}
+
+	models := make([]ResourceModel, len(links))
+	for i, link := range links {
+		models[i] = MapEntityToModel(&link)
+	}
+
+	return c.JSON(http.StatusOK, models)
+}
+
 func removalHandler(c echo.Context, pool *pgxpool.Pool) error {
 	linkId := c.Param("id")
 
@@ -72,6 +126,14 @@ func AddHandlers(s *echo.Echo, pool *pgxpool.Pool) {
 		return creationHandler(ctx, pool)
 	})
 
+	gr.GET("", func(ctx echo.Context) error {
+		return allRetrievalHandler(ctx, pool)
+	})
+
+	gr.GET("/:id", func(ctx echo.Context) error {
+		return retrievalByIdHandler(ctx, pool)
+	})
+
 	gr.DELETE("/:id", func(ctx echo.Context) error {
 		return removalHandler(ctx, pool)
 	})