From ae8cbc8f456299ebf8f6437e90faef1d40fe508b Mon Sep 17 00:00:00 2001
From: Gani Georgiev <gani.georgiev@gmail.com>
Date: Mon, 24 Jul 2023 12:33:16 +0300
Subject: [PATCH] added template.Registry.LoadFS method

---
 tools/template/registry.go      | 32 ++++++++++++--
 tools/template/registry_test.go | 76 +++++++++++++++++++++++++++++++++
 2 files changed, 104 insertions(+), 4 deletions(-)

diff --git a/tools/template/registry.go b/tools/template/registry.go
index 86ddcb82..0a4c0039 100644
--- a/tools/template/registry.go
+++ b/tools/template/registry.go
@@ -21,7 +21,9 @@
 package template
 
 import (
+	"fmt"
 	"html/template"
+	"io/fs"
 	"strings"
 
 	"github.com/pocketbase/pocketbase/tools/store"
@@ -43,16 +45,18 @@ type Registry struct {
 	cache *store.Store[*Renderer]
 }
 
-// LoadFiles caches (if not already) the specified files set as a
+// LoadFiles caches (if not already) the specified filenames set as a
 // single template and returns a ready to use Renderer instance.
-func (r *Registry) LoadFiles(files ...string) *Renderer {
-	key := strings.Join(files, ",")
+//
+// There must be at least 1 filename specified.
+func (r *Registry) LoadFiles(filenames ...string) *Renderer {
+	key := strings.Join(filenames, ",")
 
 	found := r.cache.Get(key)
 
 	if found == nil {
 		// parse and cache
-		tpl, err := template.ParseFiles(files...)
+		tpl, err := template.ParseFiles(filenames...)
 		found = &Renderer{template: tpl, parseError: err}
 		r.cache.Set(key, found)
 	}
@@ -74,3 +78,23 @@ func (r *Registry) LoadString(text string) *Renderer {
 
 	return found
 }
+
+// LoadString caches (if not already) the specified fs and globPatterns
+// pair as single template and returns a ready to use Renderer instance.
+//
+// There must be at least 1 file matching the provided globPattern(s)
+// (note that most file names serves as glob patterns matching themselves).
+func (r *Registry) LoadFS(fs fs.FS, globPatterns ...string) *Renderer {
+	key := fmt.Sprintf("%v%v", fs, globPatterns)
+
+	found := r.cache.Get(key)
+
+	if found == nil {
+		// parse and cache
+		tpl, err := template.ParseFS(fs, globPatterns...)
+		found = &Renderer{template: tpl, parseError: err}
+		r.cache.Set(key, found)
+	}
+
+	return found
+}
diff --git a/tools/template/registry_test.go b/tools/template/registry_test.go
index b1b5a124..4a2147a9 100644
--- a/tools/template/registry_test.go
+++ b/tools/template/registry_test.go
@@ -1,6 +1,7 @@
 package template
 
 import (
+	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
@@ -138,3 +139,78 @@ func TestRegistryLoadString(t *testing.T) {
 		}
 	})
 }
+
+func TestRegistryLoadFS(t *testing.T) {
+	r := NewRegistry()
+
+	t.Run("invalid fs", func(t *testing.T) {
+		fs := os.DirFS("__missing__")
+
+		files := []string{"missing1", "missing2"}
+
+		key := fmt.Sprintf("%v%v", fs, files)
+
+		r.LoadFS(fs, files...)
+
+		renderer := r.cache.Get(key)
+
+		if renderer == nil {
+			t.Fatal("Expected renderer to be initialized even if invalid, got nil")
+		}
+
+		if renderer.template != nil {
+			t.Fatalf("Expected renderer template to be nil, got %v", renderer.template)
+		}
+
+		if renderer.parseError == nil {
+			t.Fatalf("Expected renderer parseError to be set, got nil")
+		}
+	})
+
+	t.Run("valid fs", func(t *testing.T) {
+		// create test templates
+		dir, err := os.MkdirTemp(os.TempDir(), "template_test2")
+		if err != nil {
+			t.Fatal(err)
+		}
+		if err := os.WriteFile(filepath.Join(dir, "base.html"), []byte(`Base:{{template "content"}}`), 0644); err != nil {
+			t.Fatal(err)
+		}
+		if err := os.WriteFile(filepath.Join(dir, "content.html"), []byte(`{{define "content"}}Content:123{{end}}`), 0644); err != nil {
+			t.Fatal(err)
+		}
+		defer os.RemoveAll(dir)
+
+		fs := os.DirFS(dir)
+
+		files := []string{"base.html", "content.html"}
+
+		key := fmt.Sprintf("%v%v", fs, files)
+
+		r.LoadFS(fs, files...)
+
+		renderer := r.cache.Get(key)
+
+		if renderer == nil {
+			t.Fatal("Expected renderer to be initialized even if invalid, got nil")
+		}
+
+		if renderer.template == nil {
+			t.Fatal("Expected renderer template to be set, got nil")
+		}
+
+		if renderer.parseError != nil {
+			t.Fatalf("Expected renderer parseError to be nil, got %v", renderer.parseError)
+		}
+
+		result, err := renderer.Render(nil)
+		if err != nil {
+			t.Fatalf("Unexpected Render() error, got %v", err)
+		}
+
+		expected := "Base:Content:123"
+		if result != expected {
+			t.Fatalf("Expected Render() result %q, got %q", expected, result)
+		}
+	})
+}