Golang html/template versus Python Jinja2 (6) - Template Inheritance (Extends)

March 08, 2015

Template inheritance is a powerful feature of Jinja2. Here we show how to mimic the template extends of Jinja2 in Go html/template.

Go html/template versue Python Jinja2 - Template Inheritance (Extends)

Go html/template Python Jinja2

"base" template:

{{define "base"}}
<!doctype html>
<html>
<head>
  <meta charset="utf-8">
  <title>{{template "title" .}}</title>
</head>
<body>
{{template "content" .}}
</body>
</html>
{{end}}

"base" template:

<!doctype html>
<html>
<head>
  <meta charset="utf-8">
  <title>{% block title %}{% endblock %}</title>
</head>
<body>
{% block content %}{% endblock %}
</body>
</html>

index.html:

{{template "base" .}}
{{define "title"}}my title{{end}}
{{define "content"}}
<div>hello {{.}}</div>
{{end}}

index.html:

{% extends "base.html" %}
{% block title %}my title{% endblock %}
{% block content %}
<div>hello {{ name }}</div>
{% endblock %}

Complete Go html/template source code:

base-go.html | repository | view raw

{{define "base"}}
<!doctype html>
<html>
<head>
  <meta charset="utf-8">
  <title>{{template "title" .}}</title>
</head>
<body>
{{template "content" .}}
</body>
</html>
{{end}}

index-go.html | repository | view raw

{{template "base" .}}
{{define "title"}}my title{{end}}
{{define "content"}}
<div>hello {{.}}</div>
{{end}}

extends.go | repository | view raw

package main

import (
	"html/template"
	"os"
)

func main() {
	// cannot put base-go.html before index-go.html
	// the following will give empty output
	//t, _ := template.ParseFiles("base-go.html", "index-go.html")
	t, _ := template.ParseFiles("index-go.html", "base-go.html")
	name := "world"
	t.Execute(os.Stdout, name)
}

Complete Python Jinja2 source code:

base.html | repository | view raw

<!doctype html>
<html>
<head>
  <meta charset="utf-8">
  <title>{% block title %}{% endblock %}</title>
</head>
<body>
{% block content %}{% endblock %}
</body>
</html>

index.html | repository | view raw

{% extends "base.html" %}
{% block title %}my title{% endblock %}
{% block content %}
<div>hello {{ name }}</div>
{% endblock %}

extends.py | repository | view raw

#!/usr/bin/env python
# -*- coding:utf-8 -*-

import jinja2
import os


JINJA_ENVIRONMENT = jinja2.Environment(
    loader=jinja2.FileSystemLoader(os.path.dirname(__file__)),
    extensions=['jinja2.ext.autoescape'],
    autoescape=True)


if __name__ == '__main__':
  template_values = {
    'name': 'world',
  }
  template = JINJA_ENVIRONMENT.get_template('index.html')
  print(template.render(template_values))

Tested on: Ubuntu Linux 14.10, Go 1.4, Python 2.7.8, Jinja2 2.7.3

Golang html/template versus Python Jinja2 series:

[1]Golang html/template versus Python Jinja2 (1)

[2]Golang html/template versus Python Jinja2 (2)

[3]Golang html/template versus Python Jinja2 (3) - Arrays and Slices

[4]Golang html/template versus Python Jinja2 (4) - Arrays and Slices Index

[5]Golang html/template versus Python Jinja2 (5) - Maps and Dictionaries

[6]Golang html/template versus Python Jinja2 (6) - Template Inheritance (Extends)

[7]Golang html/template versus Python Jinja2 (7) - Custom Functions and Filters

References:

[a]Template Inheritance - Jinja2 Documentation

[b]Nested template definitions - template - The Go Programming Language