feat: improve error handling (#85)

Author: abemedia

encoding/text/encode.go

@@ -49,10 +49,10 @@ func encode(ctx *fasthttp.RequestCtx, v any) error {
 			b = strconv.AppendFloat(ctx.Response.Body(), v, 'f', -1, 64)
 		case bool:
 			b = strconv.AppendBool(ctx.Response.Body(), v)
-		case error:
-			b = byteconv.Atob(v.Error())
 		case encoding.TextMarshaler:
 			b, err = v.MarshalText()
+		case error:
+			b = byteconv.Atob(v.Error())
 		case fmt.Stringer:
 			b = append(ctx.Response.Body(), v.String()...)
 		default:

errors.go

@@ -34,16 +34,16 @@ func (e *HTTPError) Error() string {
 }
 
 func (e *HTTPError) StatusCode() int {
+	if e.code != 0 {
+		return e.code
+	}
+
 	var sc StatusCoder
 	if errors.As(e.err, &sc) {
 		return sc.StatusCode()
 	}
 
-	if e.code == 0 {
-		return http.StatusInternalServerError
-	}
-
-	return e.code
+	return http.StatusInternalServerError
 }
 
 func (e *HTTPError) MarshalText() ([]byte, error) {
@@ -117,34 +117,3 @@ func (e StatusError) Error() string {
 func (e StatusError) StatusCode() int {
 	return int(e)
 }
-
-func (e StatusError) MarshalText() ([]byte, error) {
-	return byteconv.Atob(e.Error()), nil
-}
-
-func (e StatusError) MarshalJSON() ([]byte, error) {
-	var buf bytes.Buffer
-
-	buf.WriteString(`{"message":`)
-	buf.WriteString(strconv.Quote(e.Error()))
-	buf.WriteRune('}')
-
-	return buf.Bytes(), nil
-}
-
-func (e StatusError) MarshalXML(enc *xml.Encoder, _ xml.StartElement) error {
-	start := xml.StartElement{Name: xml.Name{Local: "message"}}
-	return enc.EncodeElement(e.Error(), start)
-}
-
-func (e StatusError) MarshalYAML() (any, error) {
-	return map[string]string{"message": e.Error()}, nil
-}
-
-var (
-	_ error                  = (*StatusError)(nil)
-	_ encoding.TextMarshaler = (*StatusError)(nil)
-	_ json.Marshaler         = (*StatusError)(nil)
-	_ xml.Marshaler          = (*StatusError)(nil)
-	_ yaml.Marshaler         = (*StatusError)(nil)
-)

handler.go

@@ -55,18 +55,16 @@ func H[T, O any](handle Handle[T, O]) httprouter.Handle { //nolint:gocognit,cycl
 			return
 		}
 
-		req := new(T)
-
 		var (
+			req = new(T)
 			res any
-			e   *HTTPError
 		)
 
 		// Decode the header.
 		if decodeHeader != nil {
 			err = decodeHeader.Decode(&ctx.Request.Header, req)
 			if err != nil {
-				e = Error(err, http.StatusBadRequest)
+				res = Error(err, http.StatusBadRequest)
 				goto Encode
 			}
 		}
@@ -76,7 +74,7 @@ func H[T, O any](handle Handle[T, O]) httprouter.Handle { //nolint:gocognit,cycl
 			if q := ctx.URI().QueryArgs(); q.Len() > 0 {
 				err := decodeQuery.Decode(q, req)
 				if err != nil {
-					e = Error(err, http.StatusBadRequest)
+					res = Error(err, http.StatusBadRequest)
 					goto Encode
 				}
 			}
@@ -86,7 +84,7 @@ func H[T, O any](handle Handle[T, O]) httprouter.Handle { //nolint:gocognit,cycl
 		if decodePath != nil && len(p) != 0 {
 			err := decodePath.Decode(p, req)
 			if err != nil {
-				e = Error(err, http.StatusBadRequest)
+				res = Error(ErrNotFound, 0)
 				goto Encode
 			}
 		}
@@ -95,28 +93,24 @@ func H[T, O any](handle Handle[T, O]) httprouter.Handle { //nolint:gocognit,cycl
 		if ctx.Request.Header.ContentLength() > 0 {
 			dec, err := getDecoder(getEncoding(ctx.Request.Header.ContentType()))
 			if err != nil {
-				res = err
+				res = Error(err, 0)
 				goto Encode
 			}
 
 			if err := dec(ctx, req); err != nil {
-				e = Error(err, http.StatusBadRequest)
+				res = Error(err, getStatusCode(err, http.StatusBadRequest))
 				goto Encode
 			}
 		}
 
 		res, err = handle(ctx, *req)
 		if err != nil {
-			e = Error(err, 0)
+			res = Error(err, 0)
 		}
 
 	Encode:
 		ctx.SetContentType(contentType + "; charset=utf-8")
 
-		if e != nil {
-			res = e
-		}
-
 		if h, ok := res.(Headerer); ok {
 			for k, v := range h.Header() {
 				ctx.Response.Header.Set(k, v[0])
@@ -139,13 +133,12 @@ func H[T, O any](handle Handle[T, O]) httprouter.Handle { //nolint:gocognit,cycl
 }
 
 func handleError(ctx *fasthttp.RequestCtx, err error) {
-	if statusCoder, ok := err.(StatusCoder); ok { //nolint:errorlint
-		if sc := statusCoder.StatusCode(); sc < http.StatusInternalServerError {
-			ctx.Error(err.Error()+"\n", sc)
-			return
-		}
+	code := getStatusCode(err, http.StatusInternalServerError)
+	if code < http.StatusInternalServerError {
+		ctx.Error(err.Error()+"\n", code)
+		return
 	}
-	ctx.Error(fasthttp.StatusMessage(http.StatusInternalServerError)+"\n", http.StatusInternalServerError)
+	ctx.Error(fasthttp.StatusMessage(code)+"\n", code)
 	ctx.Logger().Printf("%v", err)
 }
 
@@ -158,6 +151,13 @@ func getEncoding(b []byte) string {
 	return byteconv.Btoa(bytes.TrimSpace(b))
 }
 
+func getStatusCode(i any, fallback int) int {
+	if sc, ok := i.(StatusCoder); ok {
+		return sc.StatusCode()
+	}
+	return fallback
+}
+
 const (
 	headerTag = "header"
 	pathTag   = "path"