From 9a4a4ea66a13546ec8bcd220fd063b25f4c3ef24 Mon Sep 17 00:00:00 2001
From: dylanhitt <dylan.hitt1@gmail.com>
Date: Fri, 14 Feb 2025 12:44:34 -0500
Subject: [PATCH] feat: expose HandleHTTPError for use WithErrorHandler option

---
 engine_test.go |  9 +++++++++
 errors.go      | 14 +++++++++++---
 errors_test.go | 22 ++++++++++++++++++++++
 3 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/engine_test.go b/engine_test.go
index 6fc62572..19042085 100644
--- a/engine_test.go
+++ b/engine_test.go
@@ -18,6 +18,15 @@ func TestWithErrorHandler(t *testing.T) {
 		errResponse := e.ErrorHandler(err)
 		require.ErrorAs(t, errResponse, &HTTPError{})
 	})
+	t.Run("with HandleHTTPError", func(t *testing.T) {
+		e := NewEngine(
+			WithErrorHandler(HandleHTTPError),
+		)
+		err := errors.New("Not Found :c")
+		errResponse := e.ErrorHandler(err)
+		require.ErrorAs(t, errResponse, &HTTPError{})
+		require.ErrorContains(t, errResponse, "500 Internal Server Error")
+	})
 	t.Run("custom handler", func(t *testing.T) {
 		e := NewEngine(
 			WithErrorHandler(func(err error) error {
diff --git a/errors.go b/errors.go
index fd37a0ce..33d68364 100644
--- a/errors.go
+++ b/errors.go
@@ -147,7 +147,7 @@ func (e NotAcceptableError) Unwrap() error { return HTTPError(e) }
 // ErrorHandler is the default error handler used by the framework.
 // If the error is an [HTTPError] that error is returned.
 // If the error adheres to the [ErrorWithStatus] and/or [ErrorWithDetail] interface
-// the error is transformed to a [HTTPError].
+// the error is transformed to a [HTTPError] using [HandleHTTPError].
 // If the error is not an [HTTPError] nor does it adhere to an
 // interface the error is returned as is.
 func ErrorHandler(err error) error {
@@ -155,13 +155,21 @@ func ErrorHandler(err error) error {
 	switch {
 	case errors.As(err, &HTTPError{}),
 		errors.As(err, &errorStatus):
-		return handleHTTPError(err)
+		return HandleHTTPError(err)
 	}
 
 	return err
 }
 
-func handleHTTPError(err error) HTTPError {
+// HandleHTTPError is the core logic
+// of handling fuego [HTTPError]'s. This
+// function takes any error and coerces it into a fuego HTTPError.
+// This can be used override the default handler:
+//
+//	engine := fuego.NewEngine(
+//		WithErrorHandler(HandleHTTPError),
+//	)
+func HandleHTTPError(err error) error {
 	errResponse := HTTPError{
 		Err: err,
 	}
diff --git a/errors_test.go b/errors_test.go
index 0fea5b14..8a7dfa68 100644
--- a/errors_test.go
+++ b/errors_test.go
@@ -116,6 +116,28 @@ func TestErrorHandler(t *testing.T) {
 	})
 }
 
+func TestHandleHTTPError(t *testing.T) {
+	t.Run("should always be HTTPError", func(t *testing.T) {
+		err := errors.New("test error")
+
+		errResponse := HandleHTTPError(err)
+		require.ErrorAs(t, errResponse, &HTTPError{})
+		require.ErrorContains(t, errResponse, "500 Internal Server Error")
+	})
+
+	t.Run("not found error", func(t *testing.T) {
+		err := NotFoundError{
+			Err: errors.New("Not Found :c"),
+		}
+		errResponse := HandleHTTPError(err)
+		require.ErrorAs(t, errResponse, &HTTPError{})
+		require.ErrorContains(t, err, "Not Found :c")
+		require.ErrorContains(t, errResponse, "Not Found")
+		require.ErrorContains(t, errResponse, "404")
+		require.Equal(t, http.StatusNotFound, errResponse.(HTTPError).StatusCode())
+	})
+}
+
 func TestHTTPError_Error(t *testing.T) {
 	t.Run("title", func(t *testing.T) {
 		t.Run("custom title", func(t *testing.T) {