add post userbook

needed a refactor to check the id in db during dto validation

internal/myvalidator/myvalidator.go

@@ -9,23 +9,55 @@ import (
 	"git.artlef.fr/PersonalLibraryManager/internal/i18nresource"
 	"github.com/gin-gonic/gin"
 	"github.com/go-playground/validator/v10"
+	"gorm.io/gorm"
 )
 
+type HttpError struct {
+	StatusCode int
+	Err        error
+}
+
+func ValidateId(db *gorm.DB, id uint, value any) error {
+	record := map[string]any{}
+	result := db.Model(value).First(&record, id)
+	if result.Error == nil {
+		return nil
+	}
+	if errors.Is(result.Error, gorm.ErrRecordNotFound) {
+		return HttpError{
+			StatusCode: http.StatusBadRequest,
+			Err:        fmt.Errorf("Id %d could not be found for model %s", id, value),
+		}
+	} else {
+		return HttpError{
+			StatusCode: http.StatusInternalServerError,
+			Err:        result.Error,
+		}
+	}
+}
+
+func ReturnErrorsAsJsonResponse(ac *appcontext.AppContext, err error) {
+	var httpError HttpError
+	var ve validator.ValidationErrors
+	if errors.As(err, &ve) {
+		ac.C.JSON(http.StatusBadRequest, gin.H{"error": getValidationErrors(ac, &ve)})
+	} else if errors.As(err, &httpError) {
+		ac.C.JSON(httpError.StatusCode, gin.H{"error": httpError.Err})
+	} else {
+		ac.C.JSON(http.StatusInternalServerError, gin.H{"error": err})
+	}
+}
+
+func (h HttpError) Error() string {
+	return fmt.Sprintf("%d: err %v", h.StatusCode, h.Err)
+}
+
 type apiValidationError struct {
 	Field string `json:"field"`
 	Err   string `json:"error"`
 }
 
-func ManageBindingError(ac appcontext.AppContext, err error) {
-	var ve validator.ValidationErrors
-	if errors.As(err, &ve) {
-		ac.C.JSON(http.StatusBadRequest, getValidationErrors(ac, &ve))
-	} else {
-		ac.C.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
-	}
-}
-
-func getValidationErrors(ac appcontext.AppContext, ve *validator.ValidationErrors) []apiValidationError {
+func getValidationErrors(ac *appcontext.AppContext, ve *validator.ValidationErrors) []apiValidationError {
 	errors := make([]apiValidationError, len(*ve))
 	for i, fe := range *ve {
 		errors[i] = apiValidationError{
@@ -36,7 +68,7 @@ func getValidationErrors(ac appcontext.AppContext, ve *validator.ValidationError
 	return errors
 }
 
-func computeValidationMessage(ac appcontext.AppContext, fe *validator.FieldError) string {
+func computeValidationMessage(ac *appcontext.AppContext, fe *validator.FieldError) string {
 	tag := (*fe).Tag()
 	switch tag {
 	case "required":