Prebuild templates (base.html + content) at startup to avoid a file parse every page load

config/config.go

@@ -23,7 +23,8 @@ type Configuration struct {
 	}
 
 	Template struct {
-		BaseName string `json:"BaseTemplateName"`
+		BaseName    string `json:"BaseTemplateName"`
+		ContentPath string `json:"ContentPath"`
 	}
 }
 

controllers/get.go

@@ -22,7 +22,7 @@ func (g *Get) ShowHome(w http.ResponseWriter, _ *http.Request) {
 		Test: "Hello World!",
 	}
 
-	templating.RenderTemplate(g.App, w, "templates/pages/home.html", data)
+	templating.RenderTemplate(w, "templates/pages/home.html", data)
 }
 
 func (g *Get) ShowRegister(w http.ResponseWriter, r *http.Request) {
@@ -39,7 +39,7 @@ func (g *Get) ShowRegister(w http.ResponseWriter, r *http.Request) {
 		CsrfToken: CsrfToken,
 	}
 
-	templating.RenderTemplate(g.App, w, "templates/pages/register.html", data)
+	templating.RenderTemplate(w, "templates/pages/register.html", data)
 }
 
 func (g *Get) ShowLogin(w http.ResponseWriter, r *http.Request) {
@@ -56,7 +56,7 @@ func (g *Get) ShowLogin(w http.ResponseWriter, r *http.Request) {
 		CsrfToken: CsrfToken,
 	}
 
-	templating.RenderTemplate(g.App, w, "templates/pages/login.html", data)
+	templating.RenderTemplate(w, "templates/pages/login.html", data)
 }
 
 func (g *Get) Logout(w http.ResponseWriter, r *http.Request) {

env_example.json

@@ -12,6 +12,7 @@
     "HttpPort": "8090"
   },
   "Template": {
-    "BaseTemplateName": "templates/base.html"
+    "BaseTemplateName": "templates/base.html",
+    "ContentPath": "templates"
   }
 }

main.go

@@ -6,6 +6,7 @@ import (
 	"GoWeb/database"
 	"GoWeb/models"
 	"GoWeb/routes"
+	"GoWeb/templating"
 	"context"
 	"embed"
 	"errors"
@@ -67,6 +68,13 @@ func main() {
 	routes.Get(&appLoaded)
 	routes.Post(&appLoaded)
 
+	// Prepare templates
+	err = templating.BuildPages(&appLoaded)
+	if err != nil {
+		slog.Error("error building templates: " + err.Error())
+		os.Exit(1)
+	}
+
 	// Start server
 	server := &http.Server{Addr: appLoaded.Config.Listen.Ip + ":" + appLoaded.Config.Listen.Port}
 	go func() {

templating/templateHelper.go

@@ -2,45 +2,82 @@ package templating
 
 import (
 	"GoWeb/app"
+	"fmt"
 	"html/template"
+	"io/fs"
 	"log/slog"
 	"net/http"
 )
 
-// RenderTemplate renders and serves a template from the embedded filesystem optionally with given data
-func RenderTemplate(app *app.App, w http.ResponseWriter, contentPath string, data any) {
-	templatePath := app.Config.Template.BaseName
+var templates = make(map[string]*template.Template) // This is only used here, does not need to be in app.App
 
-	templateContent, err := app.Res.ReadFile(templatePath)
+func BuildPages(app *app.App) error {
+	basePath := app.Config.Template.BaseName
+
+	baseContent, err := app.Res.ReadFile(basePath)
 	if err != nil {
+		return fmt.Errorf("error reading base file: %w", err)
+	}
+
+	base, err := template.New(basePath).Parse(string(baseContent)) // Sets filepath as name and parses content
+	if err != nil {
+		return fmt.Errorf("error parsing base file: %w", err)
+	}
+
+	readFilesRecursively := func(fsys fs.FS, root string) ([]string, error) {
+		var files []string
+		err := fs.WalkDir(fsys, root, func(path string, d fs.DirEntry, err error) error {
+			if err != nil {
+				return fmt.Errorf("error walking the path %q: %w", path, err)
+			}
+			if !d.IsDir() {
+				files = append(files, path)
+			}
+			return nil
+		})
+		return files, err
+	}
+
+	// Get all file paths in the directory tree
+	filePaths, err := readFilesRecursively(app.Res, app.Config.Template.ContentPath)
+	if err != nil {
+		return fmt.Errorf("error reading files recursively: %w", err)
+	}
+
+	for _, contentPath := range filePaths { // Create a new template base + content for each page
+		content, err := app.Res.ReadFile(contentPath)
+		if err != nil {
+			return fmt.Errorf("error reading content file %s: %w", contentPath, err)
+		}
+
+		t, err := base.Clone()
+		if err != nil {
+			return fmt.Errorf("error cloning base template: %w", err)
+		}
+
+		_, err = t.Parse(string(content))
+		if err != nil {
+			return fmt.Errorf("error parsing content: %w", err)
+		}
+
+		templates[contentPath] = t
+	}
+
+	return nil
+}
+
+func RenderTemplate(w http.ResponseWriter, contentPath string, data any) {
+	t, ok := templates[contentPath]
+	if !ok {
+		err := fmt.Errorf("template not found for path: %s", contentPath)
 		slog.Error(err.Error())
-		http.Error(w, err.Error(), 500)
+		http.Error(w, "Template not found", 404)
 		return
 	}
 
-	t, err := template.New(templatePath).Parse(string(templateContent))
-	if err != nil {
-		slog.Error(err.Error())
-		http.Error(w, err.Error(), 500)
-		return
-	}
-
-	content, err := app.Res.ReadFile(contentPath)
-	if err != nil {
-		slog.Error(err.Error())
-		http.Error(w, err.Error(), 500)
-		return
-	}
-
-	t, err = t.Parse(string(content))
-	if err != nil {
-		slog.Error(err.Error())
-		http.Error(w, err.Error(), 500)
-		return
-	}
-
-	err = t.Execute(w, data)
+	err := t.Execute(w, data) // Execute prebuilt template with dynamic data
 	if err != nil {
+		err = fmt.Errorf("error executing template: %w", err)
 		slog.Error(err.Error())
 		http.Error(w, err.Error(), 500)
 		return