echoHTMLTemplate.go

package main

import (
	"errors"
	"html/template"
	"io"
	"io/ioutil"

	"github.com/labstack/echo"
)

//ErrLastCharactorOfDirectoryPathMustBeSlash ErrLastCharactorOfDirectoryPathMustBeSlash
var ErrLastCharactorOfDirectoryPathMustBeSlash error = errors.New("Last Charactor Of Directory Path Must Be Slash")

//Template template
type Template struct {
	templates map[string]*template.Template
}

//NewTemplate creates new template of html
func NewTemplate() *Template {
	return &Template{
		templates: make(map[string]*template.Template),
	}
}

//Render rendered
func (t *Template) Render(w io.Writer, htmlName string, data interface{}, c echo.Context) error {

	if tmpl, exist := t.templates[htmlName]; exist {
		return tmpl.ExecuteTemplate(w, "page", data)
	}
	return errors.New("There is no " + htmlName + " in Template map.")

}

//AddFilesInDirectory adds all of files in directoryPath to called template object.
func (t *Template) AddFilesInDirectory(directoryPath string, nav string, footer string) error {
	if string(directoryPath[len(directoryPath)-1]) != "/" {
		return ErrLastCharactorOfDirectoryPathMustBeSlash
	}
	files, err := ioutil.ReadDir(directoryPath)
	if err != nil {
		return err
	}

	for _, file := range files {
		if file.IsDir() {
			continue
		}
		name := file.Name()
		t.templates[name] = template.Must(template.ParseFiles(nav, footer, directoryPath+name))
	}

	return nil
}