Gin meets Pongo2 !

example_pongo2.go

package main

import (
	"github.com/flosch/pongo2"
	"github.com/gin-gonic/gin"
	"net/http"
)

type pongoRender struct {
	cache map[string]*pongo2.Template
}

func newPongoRender() *pongoRender {
	return &pongoRender{map[string]*pongo2.Template{}}
}

func writeHeader(w http.ResponseWriter, code int, contentType string) {
	if code >= 0 {
		w.Header().Set("Content-Type", contentType)
		w.WriteHeader(code)
	}
}

func (p *pongoRender) Render(w http.ResponseWriter, code int, data ...interface{}) error {
	file := data[0].(string)
	ctx := data[1].(pongo2.Context)
	var t *pongo2.Template

	if tmpl, ok := p.cache[file]; ok {
		t = tmpl
	} else {
		tmpl, err := pongo2.FromFile(file)
		if err != nil {
			return err
		}
		p.cache[file] = tmpl
		t = tmpl
	}
	writeHeader(w, code, "text/html")
	return t.ExecuteRW(w, ctx)
}

func main() {
	r := gin.Default()
	r.HTMLRender = newPongoRender()

	r.GET("/index", func(c *gin.Context) {
		name := c.Request.FormValue("name")
		ctx := pongo2.Context{
			"title": "Gin with pongo2 !",
			"name":  name,
		}
		c.HTML(200, "index.html", ctx)
	})

	// Listen and server on 0.0.0.0:8080
	r.Run(":8080")
}

The interfaces Gin provides for a custom template renderer have changed a little, so this won't work anymore with the latest version of Gin.

Also, you can use pongo2.FromCache() instead of pongo2.FromFile() which means you don't need to maintain your own cache, also it's thread safe... this doesn't really look thread safe to me.