Building a simple template cache

pkg/render/render.go

@@ -3,14 +3,49 @@ package render
 import (
 	"fmt"
 	"html/template"
+	"log"
 	"net/http"
 )
 
-// renderTemplate renders a HTML template file
-func RenderTemplate(w http.ResponseWriter, tmpl string) {
-	parsedTemplate, _ := template.ParseFiles("./templates/"+tmpl, "./templates/base.layout.tmpl")
-	err := parsedTemplate.Execute(w, nil)
+var templateCache = make(map[string]*template.Template)
+
+// RenderTemplate renders a HTML template file
+func RenderTemplate(w http.ResponseWriter, t string) {
+	var tmpl *template.Template
+	var err error
+
+	// Check if the template exists already in the cache map
+	_, inMap := templateCache[t]
+	if !inMap {
+		// need to create the template
+		log.Printf("Create template cache for the template %s\n", t)
+		err = createTemplateCache(t)
 		if err != nil {
-		fmt.Println("error parsing template:", err)
+			log.Println(err)
+		}
+	}
+	tmpl = templateCache[t]
+
+	// use the template
+	err = tmpl.Execute(w, nil)
+	if err != nil {
+		log.Println(err)
 	}
 }
+
+func createTemplateCache(t string) error {
+	templates := []string{
+		fmt.Sprintf("./templates/%s", t),
+		"./templates/base.layout.tmpl",
+	}
+
+	// parse the template
+	tmpl, err := template.ParseFiles(templates...)
+	if err != err {
+		return err
+	}
+
+	// add template to cache
+	templateCache[t] = tmpl
+	return nil
+}