feat: initial version

presenter.go

@@ -0,0 +1,58 @@
+package presenter
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log/slog"
+
+	"github.com/99designs/gqlgen/graphql"
+	"github.com/vektah/gqlparser/v2/gqlerror"
+)
+
+func New[C ~string, E ~string](logger *slog.Logger, codes []C, entities []E, internalErrorCode C) func(ctx context.Context, e error) *gqlerror.Error {
+	return func(ctx context.Context, e error) *gqlerror.Error {
+		err := graphql.DefaultErrorPresenter(ctx, e)
+		var codedError CodedError
+		if errors.As(e, &codedError) {
+			code := toModelErrorCode(codedError.Code, codes, internalErrorCode)
+			errorEntity := toModelErrorEntity(codedError.Entity, entities)
+			extensions := map[string]interface{}{"code": code}
+			if len(errorEntity) > 0 {
+				extensions["errorEntity"] = errorEntity
+			}
+			if len(codedError.Params) > 0 {
+				extensions["params"] = codedError.Params
+			}
+			err.Extensions = extensions
+		} else {
+			err.Extensions = map[string]interface{}{"code": internalErrorCode}
+		}
+		if logError(e) {
+			logger.ErrorContext(ctx, fmt.Sprintf("%v", e))
+		}
+		return err
+	}
+}
+
+func logError(err error) bool {
+	return !errors.Is(err, context.Canceled)
+}
+
+func toModelErrorCode[C ~string](code Code, codes []C, internalErrorCode C) C {
+	for _, c := range codes {
+		if string(c) == string(code) {
+			return c
+		}
+	}
+	return internalErrorCode
+}
+
+func toModelErrorEntity[E ~string](entity Entity, entities []E) E {
+	for _, e := range entities {
+		if string(e) == string(entity) {
+			return e
+		}
+	}
+	return ""
+}