# [pongo](https://en.wikipedia.org/wiki/Pongo_%28genus%29)2
[](https://godoc.org/github.com/flosch/pongo2)
[](https://travis-ci.org/flosch/pongo2)
[](https://coveralls.io/r/flosch/pongo2?branch=master)
[](https://gratipay.com/flosch/)
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pongo2 is the successor of [pongo](https://github.com/flosch/pongo), a Django-syntax like templating-language.
Install/update using `go get` (no dependencies required by pongo2):
```
go get -u github.com/flosch/pongo2
```
Please use the [issue tracker](https://github.com/flosch/pongo2/issues) if you're encountering any problems with pongo2 or if you need help with implementing tags or filters ([create a ticket!](https://github.com/flosch/pongo2/issues/new)). If possible, please use [playground](https://www.florian-schlachter.de/pongo2/) to create a short test case on what's wrong and include the link to the snippet in your issue.
**New**: [Try pongo2 out in the pongo2 playground.](https://www.florian-schlachter.de/pongo2/)
## First impression of a template
```HTML+Django
Our admins and users
{# This is a short example to give you a quick overview of pongo2's syntax. #}
{% macro user_details(user, is_admin=false) %}
This user registered {{ user.register_date|naturaltime }}.
The user's biography:
{{ user.biography|markdown|truncatewords_html:15 }}
read more
{% if is_admin %}
This user is an admin!
{% endif %}
{% endmacro %}
Our admins
{% for admin in adminlist %}
{{ user_details(admin, true) }}
{% endfor %}
Our members
{% for user in userlist %}
{{ user_details(user) }}
{% endfor %}
```
## Development status
**Latest stable release**: v3.0 (`go get -u gopkg.in/flosch/pongo2.v3` / [`v3`](https://github.com/flosch/pongo2/tree/v3)-branch) [[read the announcement](https://www.florian-schlachter.de/post/pongo2-v3/)]
**Current development**: v4 (`master`-branch)
*Note*: With the release of pongo v4 the branch v2 will be deprecated.
**Deprecated versions** (not supported anymore): v1
| Topic | Status |
| ------------------------------------ | -------------------------------------------------------------------------------------- |
| Django version compatibility: | [1.7](https://docs.djangoproject.com/en/1.7/ref/templates/builtins/) |
| *Missing* (planned) **filters**: | none ([hints](https://github.com/flosch/pongo2/blob/master/filters_builtin.go#L3)) |
| *Missing* (planned) **tags**: | none ([hints](https://github.com/flosch/pongo2/blob/master/tags.go#L3)) |
Please also have a look on the [caveats](https://github.com/flosch/pongo2#caveats) and on the [official add-ons](https://github.com/flosch/pongo2#official).
## Features (and new in pongo2)
* Entirely rewritten from the ground-up.
* [Advanced C-like expressions](https://github.com/flosch/pongo2/blob/master/template_tests/expressions.tpl).
* [Complex function calls within expressions](https://github.com/flosch/pongo2/blob/master/template_tests/function_calls_wrapper.tpl).
* [Easy API to create new filters and tags](http://godoc.org/github.com/flosch/pongo2#RegisterFilter) ([including parsing arguments](http://godoc.org/github.com/flosch/pongo2#Parser))
* Additional features:
* Macros including importing macros from other files (see [template_tests/macro.tpl](https://github.com/flosch/pongo2/blob/master/template_tests/macro.tpl))
* [Template sandboxing](https://godoc.org/github.com/flosch/pongo2#TemplateSet) ([directory patterns](http://golang.org/pkg/path/filepath/#Match), banned tags/filters)
## Recent API changes within pongo2
If you're using the `master`-branch of pongo2, you might be interested in this section. Since pongo2 is still in development (even though there is a first stable release!), there could be (backwards-incompatible) API changes over time. To keep track of these and therefore make it painless for you to adapt your codebase, I'll list them here.
* Function signature for tag and filter parsing/execution changed (`error` return type changed to `*Error`).
* `INodeEvaluator` has been removed and got replaced by `IEvaluator`. You can change your existing tags/filters by simply replacing the interface.
* Two new helper functions: [`RenderTemplateFile()`](https://godoc.org/github.com/flosch/pongo2#RenderTemplateFile) and [`RenderTemplateString()`](https://godoc.org/github.com/flosch/pongo2#RenderTemplateString).
* `Template.ExecuteRW()` is now [`Template.ExecuteWriter()`](https://godoc.org/github.com/flosch/pongo2#Template.ExecuteWriter)
* `Template.Execute*()` functions do now take a `pongo2.Context` directly (no pointer anymore).
## How you can help
* Write [filters](https://github.com/flosch/pongo2/blob/master/filters_builtin.go#L3) / [tags](https://github.com/flosch/pongo2/blob/master/tags.go#L4) (see [tutorial](https://www.florian-schlachter.de/post/pongo2/)) by forking pongo2 and sending pull requests
* Write/improve code tests (use the following command to see what tests are missing: `go test -v -cover -covermode=count -coverprofile=cover.out && go tool cover -html=cover.out`)
* Write/improve template tests (see the `template_tests/` directory)
* Write middleware, libraries and websites using pongo2. :-)
# Documentation
For a documentation on how the templating language works you can [head over to the Django documentation](https://docs.djangoproject.com/en/dev/topics/templates/). pongo2 aims to be compatible with it.
You can access pongo2's API documentation on [godoc](https://godoc.org/github.com/flosch/pongo2).
## Blog post series
* [pongo2 v2 released](https://www.florian-schlachter.de/post/pongo2-v2/)
* [pongo2 1.0 released](https://www.florian-schlachter.de/post/pongo2-10/) [August 8th 2014]
* [pongo2 playground](https://www.florian-schlachter.de/post/pongo2-playground/) [August 1st 2014]
* [Release of pongo2 1.0-rc1 + pongo2-addons](https://www.florian-schlachter.de/post/pongo2-10-rc1/) [July 30th 2014]
* [Introduction to pongo2 + migration- and "how to write tags/filters"-tutorial.](https://www.florian-schlachter.de/post/pongo2/) [June 29th 2014]
## 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](http://golang.org/pkg/time/#Time.Format).
* **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.
### Tags
* **for**: All the `forloop` fields (like `forloop.counter`) are written with a capital letter at the beginning. For example, the `counter` can be accessed by `forloop.Counter` and the parentloop by `forloop.Parentloop`.
* **now**: takes Go's time format (see **date** and **time**-filter).
### 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
* [ponginae](https://github.com/flosch/ponginae) - A web-framework for Go (using pongo2).
* [pongo2-tools](https://github.com/flosch/pongo2-tools) - Official tools and helpers for pongo2
* [pongo2-addons](https://github.com/flosch/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](https://github.com/oal/beego-pongo2) - A tiny little helper for using Pongo2 with [Beego](https://github.com/astaxie/beego).
* [beego-pongo2.v2](https://github.com/ipfans/beego-pongo2.v2) - Same as `beego-pongo2`, but for pongo2 v2.
* [macaron-pongo2](https://github.com/macaron-contrib/pongo2) - pongo2 support for [Macaron](https://github.com/Unknwon/macaron), a modular web framework.
* [ginpongo2](https://github.com/ngerakines/ginpongo2) - middleware for [gin](github.com/gin-gonic/gin) to use pongo2 templates
* [pongo2-trans](https://github.com/fromYukki/pongo2trans) - `trans`-tag implementation for internationalization
Please add your project to this list and send me a pull request when you've developed something nice for pongo2.
# API-usage examples
Please see the documentation for a full list of provided API methods.
## A tiny example (template string)
```Go
// 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)
```Go
package main
import (
"github.com/flosch/pongo2"
"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)
}
```
# Benchmark
The benchmarks have been run on the my machine (`Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz`) using the command:
go test -bench . -cpu 1,2,4,8
All benchmarks are compiling (depends on the benchmark) and executing the `template_tests/complex.tpl` template.
The results are:
BenchmarkExecuteComplexWithSandboxActive 50000 60450 ns/op
BenchmarkExecuteComplexWithSandboxActive-2 50000 56998 ns/op
BenchmarkExecuteComplexWithSandboxActive-4 50000 60343 ns/op
BenchmarkExecuteComplexWithSandboxActive-8 50000 64229 ns/op
BenchmarkCompileAndExecuteComplexWithSandboxActive 10000 164410 ns/op
BenchmarkCompileAndExecuteComplexWithSandboxActive-2 10000 156682 ns/op
BenchmarkCompileAndExecuteComplexWithSandboxActive-4 10000 164821 ns/op
BenchmarkCompileAndExecuteComplexWithSandboxActive-8 10000 171806 ns/op
BenchmarkParallelExecuteComplexWithSandboxActive 50000 60428 ns/op
BenchmarkParallelExecuteComplexWithSandboxActive-2 50000 31887 ns/op
BenchmarkParallelExecuteComplexWithSandboxActive-4 100000 22810 ns/op
BenchmarkParallelExecuteComplexWithSandboxActive-8 100000 18820 ns/op
BenchmarkExecuteComplexWithoutSandbox 50000 56942 ns/op
BenchmarkExecuteComplexWithoutSandbox-2 50000 56168 ns/op
BenchmarkExecuteComplexWithoutSandbox-4 50000 57838 ns/op
BenchmarkExecuteComplexWithoutSandbox-8 50000 60539 ns/op
BenchmarkCompileAndExecuteComplexWithoutSandbox 10000 162086 ns/op
BenchmarkCompileAndExecuteComplexWithoutSandbox-2 10000 159771 ns/op
BenchmarkCompileAndExecuteComplexWithoutSandbox-4 10000 163826 ns/op
BenchmarkCompileAndExecuteComplexWithoutSandbox-8 10000 169062 ns/op
BenchmarkParallelExecuteComplexWithoutSandbox 50000 57152 ns/op
BenchmarkParallelExecuteComplexWithoutSandbox-2 50000 30276 ns/op
BenchmarkParallelExecuteComplexWithoutSandbox-4 100000 22065 ns/op
BenchmarkParallelExecuteComplexWithoutSandbox-8 100000 18034 ns/op
Benchmarked on October 2nd 2014.