refactor: form binding validation (#38832)

Make "form-fetch-action" highlight the invalid field as "error"

services/context/context.go

@@ -26,6 +26,8 @@ import (
 	"gitea.dev/modules/web"
 	"gitea.dev/modules/web/middleware"
 	web_types "gitea.dev/modules/web/types"
+
+	"gitea.com/go-chi/binding"
 )
 
 // Render represents a template render
@@ -81,17 +83,22 @@ func GetWebContext(ctx context.Context) *Context {
 	return webCtx
 }
 
-// ValidateContext is a special context for form validation middleware. It may be different from other contexts.
-type ValidateContext struct {
-	*Base
-}
-
 // GetValidateContext gets a context for middleware form validation
-func GetValidateContext(req *http.Request) (ctx *ValidateContext) {
+func GetValidateContext(req *http.Request) (ctx *middleware.ValidateContext) {
 	if ctxAPI, ok := req.Context().Value(apiContextKey).(*APIContext); ok {
-		ctx = &ValidateContext{Base: ctxAPI.Base}
+		ctx = &middleware.ValidateContext{
+			Data:   ctxAPI.Data,
+			Locale: ctxAPI.Locale,
+			Req:    ctxAPI.Req,
+			Resp:   ctxAPI.Resp,
+		}
 	} else if ctxWeb, ok := req.Context().Value(WebContextKey).(*Context); ok {
-		ctx = &ValidateContext{Base: ctxWeb.Base}
+		ctx = &middleware.ValidateContext{
+			Data:   ctxWeb.Data,
+			Locale: ctxWeb.Locale,
+			Req:    ctxWeb.Req,
+			Resp:   ctxWeb.Resp,
+		}
 	} else {
 		panic("invalid context, expect either APIContext or Context")
 	}
@@ -254,15 +261,24 @@ func (ctx *Context) JSONOK() {
 	ctx.JSON(http.StatusOK, map[string]any{"ok": true}) // this is only a dummy response, frontend seldom uses it
 }
 
-func (ctx *Context) JSONError(msg any) {
+func buildJsonErrorMap(msg any) map[string]any {
 	switch v := msg.(type) {
 	case string:
-		ctx.JSON(http.StatusBadRequest, map[string]any{"errorMessage": v, "renderFormat": "text"})
+		return map[string]any{"errorMessage": v, "renderFormat": "text"}
 	case template.HTML:
-		ctx.JSON(http.StatusBadRequest, map[string]any{"errorMessage": v, "renderFormat": "html"})
-	default:
-		panic(fmt.Sprintf("unsupported type: %T", msg))
+		return map[string]any{"errorMessage": v, "renderFormat": "html"}
 	}
+	panic(fmt.Sprintf("unsupported type: %T", msg))
+}
+
+func (ctx *Context) JSONError(msg any) {
+	ctx.JSON(http.StatusBadRequest, buildJsonErrorMap(msg))
+}
+
+func (ctx *Context) JSONErrorWithField(msg any, field string) {
+	m := buildJsonErrorMap(msg)
+	m["errorFields"] = []string{field}
+	ctx.JSON(http.StatusBadRequest, m)
 }
 
 func (ctx *Context) JSONErrorNotFound(optMsg ...string) {
@@ -270,5 +286,24 @@ func (ctx *Context) JSONErrorNotFound(optMsg ...string) {
 	if msg == "" {
 		msg = ctx.Locale.TrString("error.not_found")
 	}
-	ctx.JSON(http.StatusNotFound, map[string]any{"errorMessage": msg, "renderFormat": "text"})
+	ctx.JSON(http.StatusNotFound, buildJsonErrorMap(msg))
+}
+
+func GetFetchActionForm[T interface {
+	*E
+	middleware.Form
+}, E any](ctx *Context) *E {
+	if web.IsFormSet(ctx) {
+		panic("don't mix fetch-action form validation with template-based form validation")
+	}
+	middleware.SkipTmplFormValidationError(ctx)
+	form := T(new(E))
+	errs := binding.Bind(ctx.Req, form)
+	errorMessage, fieldName, _ := middleware.BuildValidationErrorForUser(form, ctx.Locale, errs)
+	if errorMessage != "" {
+		ctx.Resp.Header().Set("Content-Type", "application/json")
+		ctx.JSONErrorWithField(errorMessage, fieldName)
+		return nil
+	}
+	return form
 }