view: allow only-custom template parsing

view/amber.go

@@ -13,6 +13,8 @@ import (
 	"sync"
 	"sync/atomic"
 
+	"github.com/kataras/iris/v12/context"
+
 	"github.com/eknkc/amber"
 )
 
@@ -152,6 +154,11 @@ func (s *AmberEngine) AddFunc(funcName string, funcBody interface{}) {
 //
 // Returns an error if something bad happens, user is responsible to catch it.
 func (s *AmberEngine) Load() error {
+	// If only custom templates should be loaded.
+	if (s.fs == nil || context.IsNoOpFS(s.fs)) && len(s.templateCache) > 0 {
+		return nil
+	}
+
 	rootDirName := getRootDirName(s.fs)
 
 	return walk(s.fs, "", func(path string, info os.FileInfo, err error) error {

view/django.go

@@ -222,6 +222,11 @@ func (s *DjangoEngine) RegisterTag(tagName string, fn TagParser) error {
 //
 // Returns an error if something bad happens, user is responsible to catch it.
 func (s *DjangoEngine) Load() error {
+	// If only custom templates should be loaded.
+	if (s.fs == nil || context.IsNoOpFS(s.fs)) && len(s.templateCache) > 0 {
+		return nil
+	}
+
 	rootDirName := getRootDirName(s.fs)
 
 	return walk(s.fs, "", func(path string, info os.FileInfo, err error) error {

view/handlebars.go

@@ -10,6 +10,8 @@ import (
 	"strings"
 	"sync"
 
+	"github.com/kataras/iris/v12/context"
+
 	"github.com/mailgun/raymond/v2"
 )
 
@@ -134,6 +136,11 @@ func (s *HandlebarsEngine) AddGlobalFunc(funcName string, funcBody interface{})
 //
 // Returns an error if something bad happens, user is responsible to catch it.
 func (s *HandlebarsEngine) Load() error {
+	// If only custom templates should be loaded.
+	if (s.fs == nil || context.IsNoOpFS(s.fs)) && len(s.templateCache) > 0 {
+		return nil
+	}
+
 	rootDirName := getRootDirName(s.fs)
 
 	return walk(s.fs, "", func(path string, info os.FileInfo, _ error) error {

view/html.go

@@ -10,6 +10,8 @@ import (
 	"path/filepath"
 	"strings"
 	"sync"
+
+	"github.com/kataras/iris/v12/context"
 )
 
 // HTMLEngine contains the html view engine structure.
@@ -61,7 +63,8 @@ var (
 // Usage:
 // HTML("./views", ".html") or
 // HTML(iris.Dir("./views"), ".html") or
-// HTML(embed.FS, ".html") or HTML(AssetFile(), ".html") for embedded data.
+// HTML(embed.FS, ".html") or HTML(AssetFile(), ".html") for embedded data or
+// HTML("","").ParseTemplate("hello", `[]byte("hello {{.Name}}")`, nil) for custom template parsing only.
 func HTML(dirOrFS interface{}, extension string) *HTMLEngine {
 	s := &HTMLEngine{
 		name:      "HTML",
@@ -243,6 +246,11 @@ func (s *HTMLEngine) load() error {
 		return err
 	}
 
+	// If only custom templates should be loaded.
+	if (s.fs == nil || context.IsNoOpFS(s.fs)) && len(s.Templates.DefinedTemplates()) > 0 {
+		return nil
+	}
+
 	rootDirName := getRootDirName(s.fs)
 
 	err := walk(s.fs, "", func(path string, info os.FileInfo, err error) error {