pongo2

pongo2 is a Django-syntax like templating-language (official website).

Install/update using go get (no dependencies required by pongo2):

go get -u github.com/flosch/pongo2/v6

Please use the issue tracker if you're encountering any problems with pongo2 or if you need help with implementing tags or filters (create a ticket!).

❓ Looking for a Go developer/consultant? I'm available for hire. 👨‍💻

First impression of a template

<html>
  <head>
    <title>Our admins and users</title>
  </head>
  {# This is a short example to give you a quick overview of pongo2's syntax. #}
  {% macro user_details(user, is_admin=false) %}
  <div class="user_item">
    <!-- Let's indicate a user's good karma -->
    <h2 {% if (user.karma>= 40) || (user.karma > calc_avg_karma(userlist)+5) %} class="karma-good"{% endif %}>

      <!-- This will call user.String() automatically if available: -->
      {{ user }}
    </h2>

    <!-- Will print a human-readable time duration like "3 weeks ago" -->
    <p>This user registered {{ user.register_date|naturaltime }}.</p>

    <!-- Let's allow the users to write down their biography using markdown;
             we will only show the first 15 words as a preview -->
    <p>The user's biography:</p>
    <p>
      {{ user.biography|markdown|truncatewords_html:15 }}
      <a href="/user/{{ user.id }}/">read more</a>
    </p>

    {% if is_admin %}
    <p>This user is an admin!</p>
    {% endif %}
  </div>
  {% endmacro %}

  <body>
    <!-- Make use of the macro defined above to avoid repetitive HTML code
         since we want to use the same code for admins AND members -->

    <h1>Our admins</h1>
    {% for admin in adminlist %} {{ user_details(admin, true) }} {% endfor %}

    <h1>Our members</h1>
    {% for user in userlist %} {{ user_details(user) }} {% endfor %}
  </body>
</html>

Features

Syntax- and feature-set-compatible with Django 1.7
Advanced C-like expressions.
Complex function calls within expressions.
Easy API to create new filters and tags (including parsing arguments)
Additional features:
- Macros including importing macros from other files (see template_tests/macro.tpl)
- Template sandboxing (directory patterns, banned tags/filters)

Caveats

Filters

date / time: The date and time filter are taking the Golang specific time- and date-format (not Django's one) currently. Take a look on the format here.
stringformat: stringformat does not take Python's string format syntax as a parameter, instead it takes Go's. Essentially {{ 3.14|stringformat:"pi is %.2f" }} is fmt.Sprintf("pi is %.2f", 3.14).
escape / force_escape: Unlike Django's behaviour, the escape-filter is applied immediately. Therefore there is no need for a force_escape-filter yet.

Misc

not in-operator: You can check whether a map/struct/string contains a key/field/substring by using the in-operator (or the negation of it): {% if key in map %}Key is in map{% else %}Key not in map{% endif %} or {% if !(key in map) %}Key is NOT in map{% else %}Key is in map{% endif %}.

Add-ons, libraries and helpers

Official

pongo2-addons - Official additional filters/tags for pongo2 (for example a markdown-filter). They are in their own repository because they're relying on 3rd-party-libraries.

3rd-party

beego-pongo2 - A tiny little helper for using Pongo2 with Beego.
beego-pongo2.v2 - Same as beego-pongo2, but for pongo2 v2.
macaron-pongo2 - pongo2 support for Macaron, a modular web framework.
ginpongo2 - middleware for gin to use pongo2 templates
Build'n support for Iris' template engine
pongo2gin - alternative renderer for gin to use pongo2 templates
pongo2-trans - trans-tag implementation for internationalization
tpongo2 - pongo2 support for Tango, a micro-kernel & pluggable web framework.
p2cli - command line templating utility based on pongo2
pongorenderer - minimal pongo2 renderer for Echo web framework
pongo2gcloud - Google Cloud Storage loader for pongo2 template files

Please add your project to this list and send me a pull request when you've developed something nice for pongo2.

Who's using pongo2

I'm compiling a list of pongo2 users. Add your project or company!

API-usage examples

Please see the documentation for a full list of provided API methods.

A tiny example (template string)

// Compile the template first (i. e. creating the AST)
tpl, err := pongo2.FromString("Hello {{ name|capfirst }}!")
if err != nil {
    panic(err)
}
// Now you can render the template with the given
// pongo2.Context how often you want to.
out, err := tpl.Execute(pongo2.Context{"name": "florian"})
if err != nil {
    panic(err)
}
fmt.Println(out) // Output: Hello Florian!

Example server-usage (template file)

package main

import (
    "github.com/flosch/pongo2/v6"
    "net/http"
)

// Pre-compiling the templates at application startup using the
// little Must()-helper function (Must() will panic if FromFile()
// or FromString() will return with an error - that's it).
// It's faster to pre-compile it anywhere at startup and only
// execute the template later.
var tplExample = pongo2.Must(pongo2.FromFile("example.html"))

func examplePage(w http.ResponseWriter, r *http.Request) {
    // Execute the template per HTTP request
    err := tplExample.ExecuteWriter(pongo2.Context{"query": r.FormValue("query")}, w)
    if err != nil {
        http.Error(w, err.Error(), http.StatusInternalServerError)
    }
}

func main() {
    http.HandleFunc("/", examplePage)
    http.ListenAndServe(":8080", nil)
}

flosch/pongo2