Rendering XHTML pages

[Tachi107]

Hi!

Echo's template rendering support currently unconditionally sends HTML pages with the text/html media type to the client. This is documented in the Render function.

My HTML fragments, though, use the XML syntax of HTML, also known as XHTML. This means that, for example, they lack a DOCTYPE declaration and the xml:lang attribute is used instead of lang, which makes them invalid HTML documents when sent with the text/html media type.

Is it possible to serve them with the application/xhtml+xml media type? If not, could an option to do this please be added?

Thanks!

[aldas]

something like that.

package main

import (
	"github.com/labstack/echo/v4"
	"html/template"
	"io"
	"log/slog"
	"net/http"
)

type XHTMLRenderer struct {
	Template interface {
		ExecuteTemplate(wr io.Writer, name string, data any) error
	}
}

func (t *XHTMLRenderer) Render(w io.Writer, name string, data any, c echo.Context) error {
	c.Response().Header().Set(echo.HeaderContentType, "application/xhtml+xml") // or here
	return t.Template.ExecuteTemplate(w, name, data)
}

func main() {
	e := echo.New()
	e.Renderer = &XHTMLRenderer{
		Template: template.Must(template.ParseGlob("../*.html")),
	}

	e.GET("/", func(c echo.Context) error {
		//c.Response().Header().Set(echo.HeaderContentType, "application/xhtml+xml") // here
		return c.Render(http.StatusOK, "index.html", nil)
	})

	if err := e.Start(":8080"); err != nil {
		slog.Error("failed to start server")
	}
}

both work because eventually this method is called and it will not set content type if it is already set

echo/context.go

Lines 243 to 248 in ce0b12a

	func (c *context) writeContentType(value string) {
	header := c.Response().Header()
	if header.Get(HeaderContentType) == "" {
	header.Set(HeaderContentType, value)
	}
	}

[Tachi107]

Makes sense! I like the XHTMLRenderer.Render() solution more. Thanks :)