Setting up Pongo2 with Echo v4

template.go

package web

import (
	"io"

	"github.com/flosch/pongo2/v6"
	"github.com/labstack/echo/v4"
	"github.com/spf13/viper"
)

// RenderOptions is used to configure the renderer.
type RenderOptions struct {
	TemplateDir string
	TemplateSet *pongo2.TemplateSet
	ContentType string
}

// Pongo2Render is a custom Echo template renderer using Pongo2.
type Pongo2Render struct {
	Options *RenderOptions
}

// NewRender creates a new Pongo2Render instance with custom Options.
func NewRender(options RenderOptions) (*Pongo2Render, error) {
	// If TemplateSet is nil construct a new TemplateSet for TemplateDir.
	if options.TemplateSet == nil {
		loader, err := pongo2.NewLocalFileSystemLoader(options.TemplateDir)
		if err != nil {
			return nil, err
		}
		options.TemplateSet = pongo2.NewSet(options.TemplateDir, loader)
		options.TemplateSet.Debug = viper.GetBool("debug")
	}

	render := &Pongo2Render{Options: &options}
	return render, nil
}

// DefaultRender creates a Pongo2Render instance with default options.
func DefaultRender() (*Pongo2Render, error) {
	return NewRender(RenderOptions{
		TemplateDir: viper.GetString("template_dir"),
		TemplateSet: nil,
		ContentType: echo.MIMETextHTMLCharsetUTF8,
	})
}

// Render is an interface function that renders a Pongo2 template as an HTML response.
func (p *Pongo2Render) Render(w io.Writer, name string, data interface{}, c echo.Context) error {
	template, err := p.Options.TemplateSet.FromCache(name)
	if err != nil {
		return err
	}

	c.Response().Header().Set(echo.HeaderContentType, p.Options.ContentType)
	return template.ExecuteWriter(data.(pongo2.Context), w)
}

Also this probably should come with a "how to use", here goes:

e := echo.New()
e.Debug = viper.GetBool("debug")

// Setup the Pongo2 renderer
render, err := DefaultRender()
if err != nil {
	// handle or return error (e.g. template dir does not exist could return an error)
}
e.Renderer = render

// Start Echo
e.Logger.Fatal(e.Start(":8080"))

The reason I am using TemplateSet actually originated in my pongo2gin repo on Gitlab (gitlab.com/go-box/pongo2gin), a contributor needed this and added support for template sets. I since cleaned it up, refactored it, and translated the code to use Echo instead of Gin.

You may notice it automatically creates a TemplateSet based on the template dir if TemplateSet was nil. Otherwise it will use the TemplateSet you pass in.