From 1adbae211ed9da3fc8d024b193d7e24e0c1414eb Mon Sep 17 00:00:00 2001
From: kolaente <k@knt.li>
Date: Sat, 29 Aug 2026 00:48:55 +0200
Subject: [PATCH] refactor(validation): move govalidator rules and struct
 validation into models

---
 pkg/models/validation.go | 77 ++++++++++++++++++++++++++++++++++++++++
 pkg/routes/validation.go | 36 +------------------
 2 files changed, 78 insertions(+), 35 deletions(-)
 create mode 100644 pkg/models/validation.go

diff --git a/pkg/models/validation.go b/pkg/models/validation.go
new file mode 100644
index 000000000..fb24839cd
--- /dev/null
+++ b/pkg/models/validation.go
@@ -0,0 +1,77 @@
+// Vikunja is a to-do list application to facilitate your life.
+// Copyright 2018-present Vikunja and contributors. All rights reserved.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package models
+
+import (
+	"sort"
+
+	"code.vikunja.io/api/pkg/db"
+
+	"github.com/asaskevich/govalidator"
+)
+
+// The `valid:` tag rules live on the models, so the custom validators they
+// reference are registered here rather than in the HTTP layer — every entry
+// point that validates a model (echo's CustomValidator, /api/v2, MCP)
+// imports this package and therefore gets them.
+func init() {
+	govalidator.TagMap["time"] = func(str string) bool {
+		return govalidator.IsTime(str, "15:04")
+	}
+
+	// Adapts to the database in use: MySQL TEXT tops out far below what
+	// PostgreSQL and SQLite accept.
+	govalidator.TagMap["dbtext"] = func(str string) bool {
+		maxLength := 65000
+		if dialect := db.GetDialect(); dialect == "postgres" || dialect == "sqlite3" {
+			maxLength = 1048576
+		}
+		return len(str) <= maxLength
+	}
+}
+
+// ValidateStruct checks a model against its `valid:` struct tags and reports
+// every failure as an InvalidFieldError.
+func ValidateStruct(i interface{}) error {
+	return ValidateStructFields(i, nil)
+}
+
+// ValidateStructFields is ValidateStruct restricted to the given field names
+// (JSON names, or Go field names for `json:"-"` fields). Callers that build a
+// model from a partial payload need this: a `required` rule must not fire for
+// a field the caller never sent. A nil set means "report everything".
+func ValidateStructFields(i interface{}, only map[string]bool) error {
+	_, err := govalidator.ValidateStruct(i)
+	if err == nil {
+		return nil
+	}
+
+	var errs []string
+	for field, e := range govalidator.ErrorsByField(err) {
+		if only != nil && !only[field] {
+			continue
+		}
+		errs = append(errs, field+": "+e)
+	}
+	if len(errs) == 0 {
+		return nil
+	}
+
+	// Map iteration order is non-deterministic; sort for a stable errors[].
+	sort.Strings(errs)
+	return InvalidFieldError(errs)
+}
diff --git a/pkg/routes/validation.go b/pkg/routes/validation.go
index 64a8235ca..00d01de1b 100644
--- a/pkg/routes/validation.go
+++ b/pkg/routes/validation.go
@@ -17,47 +17,13 @@
 package routes
 
 import (
-	"code.vikunja.io/api/pkg/db"
 	"code.vikunja.io/api/pkg/models"
-
-	"github.com/asaskevich/govalidator"
 )
 
 // CustomValidator is a dummy struct to use govalidator with echo
 type CustomValidator struct{}
 
-func init() {
-	govalidator.TagMap["time"] = func(str string) bool {
-		return govalidator.IsTime(str, "15:04")
-	}
-
-	// Custom validator for database TEXT fields that adapts to the database being used
-	govalidator.TagMap["dbtext"] = func(str string) bool {
-		// Get the current database dialect
-		dialect := db.GetDialect()
-
-		// Default limit for MySQL and unknown databases (65KB safely under TEXT limit)
-		maxLength := 65000
-
-		// For databases that support larger text fields
-		if dialect == "postgres" || dialect == "sqlite3" {
-			maxLength = 1048576 // ~1MB limit for PostgreSQL and SQLite
-		}
-
-		return len(str) <= maxLength
-	}
-}
-
 // Validate validates stuff
 func (cv *CustomValidator) Validate(i interface{}) error {
-	if _, err := govalidator.ValidateStruct(i); err != nil {
-
-		var errs []string
-		for field, e := range govalidator.ErrorsByField(err) {
-			errs = append(errs, field+": "+e)
-		}
-
-		return models.InvalidFieldError(errs)
-	}
-	return nil
+	return models.ValidateStruct(i)
 }