chore: custom error

internal/handlers/restutil/error.go

@@ -0,0 +1,68 @@
+package restutil
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"log/slog"
+	"net/http"
+)
+
+type ErrorType string
+
+const (
+	ErrorTypeUndefinded  = ""
+	ErrorTypeValidation  = "VALIDATION"
+	ErrorTypeNotFound    = "NOT_FOUND"
+	ErrorTypeServerError = "SERVER_ERROR"
+)
+
+type Error struct {
+	Type    ErrorType `json:"type"`
+	Message string    `json:"message"`
+	err     error
+}
+
+func WrappErr(err error, errorType ErrorType, message string) *Error {
+	return &Error{
+		Type:    errorType,
+		Message: message,
+		err:     err,
+	}
+}
+
+func (e Error) Unwrap() error {
+	return e.err
+}
+
+func (e Error) Error() string {
+	return fmt.Sprintf("%s: %s", e.Message, e.err.Error())
+}
+
+func (e Error) StatusCode() int {
+	switch e.Type {
+	case ErrorTypeValidation:
+		return http.StatusBadRequest
+	case ErrorTypeNotFound:
+		return http.StatusNotFound
+	default:
+		return http.StatusInternalServerError
+	}
+}
+
+func SendErr(w http.ResponseWriter, err error) {
+	restErr := &Error{}
+
+	if !errors.As(err, &restErr) {
+		slog.Error("internal server error", "err", err)
+		restErr = &Error{
+			Type: ErrorTypeServerError,
+		}
+	}
+
+	w.WriteHeader(restErr.StatusCode())
+	w.Header().Add("Content-Type", "application/json")
+	err = json.NewEncoder(w).Encode(restErr)
+
+	slog.Error("could not send error", "err", err)
+}

internal/handlers/restutil/params.go

@@ -0,0 +1,24 @@
+package restutil
+
+import (
+	"fmt"
+	"net/http"
+	"strconv"
+)
+
+func IntParam(r *http.Request, key string) (val int, err error) {
+	str := r.URL.Query().Get(key)
+	if str == "" {
+		return
+	}
+
+	val, err = strconv.Atoi(str)
+	if err != nil {
+		err = WrappErr(
+			err,
+			ErrorTypeValidation,
+			fmt.Sprintf("failed to parse query parameter '%s': not an int", key),
+		)
+	}
+	return
+}