Templates

Context#Render(code int, name string, data any) error renders a template with data and sends a text/html response with a status code. Register a renderer by setting Echo#Renderer, which lets you use any template engine.

Rendering

The example below uses Go’s html/template.

Use the default template renderer:

e.Renderer = &echo.TemplateRenderer{
  Template: template.Must(template.New("hello").Parse("Hello, {{.}}!")),
}

Or implement the echo.Renderer interface yourself:

type Template struct {
  templates *template.Template
}

func (t *Template) Render(c *echo.Context, w io.Writer, name string, data any) error {
  return t.templates.ExecuteTemplate(w, name, data)
}

Pre-compile the templates.

public/views/hello.html:

{{define "hello"}}Hello, {{.}}!{{end}}

t := &Template{
    templates: template.Must(template.ParseGlob("public/views/*.html")),
}

e := echo.New()
e.Renderer = t
e.GET("/hello", Hello)

Render a template inside the handler.

func Hello(c *echo.Context) error {
    return c.Render(http.StatusOK, "hello", "World")
}

Advanced: calling Echo from templates

Sometimes it is useful to generate URIs from within a template by calling Echo#Reverse. Go’s html/template is not ideally suited for this, but it can be done in two ways: by providing a common method on every object passed to templates, or by passing a map[string]any and augmenting it in the custom renderer. The latter is more flexible. Here is a complete example.

template.html:

<html>
<body>
<h1>Hello {{index . "name"}}</h1>

<p>{{ with $x := index . "reverse" }}
   {{ call $x "foobar" }} <!--- this calls $x with the parameter "foobar" -->
   {{ end }}
</p>
</body>
</html>

server.go:

package main

import (
  "html/template"
  "io"
  "net/http"

  "github.com/labstack/echo/v5"
)

// TemplateRenderer is a custom html/template renderer for Echo.
type TemplateRenderer struct {
  templates *template.Template
}

// Render renders a template document.
func (t *TemplateRenderer) Render(c *echo.Context, w io.Writer, name string, data any) error {
  // Add global methods if the data is a map.
  if viewContext, isMap := data.(map[string]any); isMap {
    viewContext["reverse"] = c.RouteInfo().Reverse
  }

  return t.templates.ExecuteTemplate(w, name, data)
}

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

  e.GET("/something/:name", func(c *echo.Context) error {
    return c.Render(http.StatusOK, "template.html", map[string]any{
      "name": "Dolly!",
    })
  })

  if err := e.Start(":1323"); err != nil {
    e.Logger.Error("shutting down the server", "error", err)
  }
}