Use a custom template function for csrf protection

views/template.go

@@ -3,11 +3,13 @@ package views
 import (
 	"fmt"
 	"html/template"
-	"io"
 	"io/fs"
 	"log"
 	"net/http"
 	"os"
+	"strings"
+
+	"github.com/gorilla/csrf"
 )
 
 type Template struct {
@@ -15,16 +17,32 @@ type Template struct {
 }
 
 func (t Template) Execute(w http.ResponseWriter, r *http.Request, data interface{}) {
+	tpl, err := t.htmlTpl.Clone()
+	if err != nil {
+		log.Printf("Template Clone Error: %v", err)
+		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+		return
+	}
+
+	tpl = tpl.Funcs(template.FuncMap{
+		"csrfField": func() template.HTML { return csrf.TemplateField(r) },
+	})
+
 	w.Header().Set("Content-Type", "text/html; charset=utf8")
-	err := t.htmlTpl.Execute(w, data)
+	err = tpl.Execute(w, data)
 	if err != nil {
 		log.Printf("Error executing template: %v", err)
 		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
 		return
 	}
 }
-func (t Template) ExecuteWriter(w io.Writer, data interface{}) error {
-	return t.htmlTpl.Execute(w, data)
+func (t Template) TestTemplate(data interface{}) error {
+	var testWriter strings.Builder
+	tpl, err := t.htmlTpl.Clone()
+	if err != nil {
+		return err
+	}
+	return tpl.Execute(&testWriter, data)
 }
 
 func FromFile(pattern ...string) (Template, error) {
@@ -32,7 +50,13 @@ func FromFile(pattern ...string) (Template, error) {
 	return FromFS(fs, pattern...)
 }
 func FromFS(fs fs.FS, pattern ...string) (Template, error) {
-	tpl, err := template.ParseFS(fs, pattern...)
+	tpl := template.New(pattern[0])
+	tpl = tpl.Funcs(template.FuncMap{
+		"csrfField": func() template.HTML {
+			return `<div class="hidden">STUB: PLACEHOLDER</div>`
+		},
+	})
+	tpl, err := tpl.ParseFS(fs, pattern...)
 	if err != nil {
 		return Template{}, fmt.Errorf("Error parsing template: %v", err)
 	}