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

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