Second checkpoint

internal/transport/http/errors.go

@@ -0,0 +1,24 @@
+package http
+
+import (
+	"errors"
+	"net/http"
+
+	"gis/internal/domain"
+	"gis/pkg/httputil"
+)
+
+// respondDomainError maps a domain error to an HTTP status and writes a JSON
+// error envelope.
+func respondDomainError(w http.ResponseWriter, err error) {
+	switch {
+	case errors.Is(err, domain.ErrNotFound):
+		httputil.WriteError(w, http.StatusNotFound, "not found")
+	case errors.Is(err, domain.ErrValidation):
+		httputil.WriteError(w, http.StatusUnprocessableEntity, err.Error())
+	case errors.Is(err, domain.ErrConflict):
+		httputil.WriteError(w, http.StatusConflict, "operation conflicts with existing data")
+	default:
+		httputil.WriteError(w, http.StatusInternalServerError, "internal server error")
+	}
+}