go-sample-webpage/pkg/webpage/layoutmiddleware.go

package webpage

import (
	"bytes"
	"github.com/unrolled/render"
	"html/template"
	"io"
	"net/http"
)

type LayoutMiddlewareResponseWriter struct {
	http.ResponseWriter
	buf *bytes.Buffer
}

func (myrw *LayoutMiddlewareResponseWriter) Write(p []byte) (int, error) {
	return myrw.buf.Write(p)
}


func TemplateMiddelware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		render := render.New(render.Options{
			Layout: "layout",
			FileSystem: &render.EmbedFileSystem{
				FS: config.Templates,
			},
		})

		rw := &LayoutMiddlewareResponseWriter{
			ResponseWriter: w,
			buf:            &bytes.Buffer{},
		}


		next.ServeHTTP(rw, r)

		content, err := io.ReadAll(rw.buf)
		if err != nil {
			panic(err)
		}

		rw.buf.Reset()
		render.HTML(w, http.StatusOK, "sub", template.HTML(string(content)))
	})
}