Awesome
pongo2
pongo2 is the successor of 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 if you're encountering any problems with pongo2 or if you need help with implementing tags or filters (create a ticket!). If possible, please use playground 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.
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>
Development status
Latest stable release: v3.0 (go get -u gopkg.in/flosch/pongo2.v3
/ v3
-branch) [read the announcement]
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 |
Missing (planned) filters: | none (hints) |
Missing (planned) tags: | none (hints) |
Please also have a look on the caveats and on the official add-ons.
Features (and new in pongo2)
- Entirely rewritten from the ground-up.
- 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)
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 execution changed: not taking a
bytes.Buffer
anymore; insteadExecute()
-functions are now taking aTemplateWriter
interface. - Function signature for tag and filter parsing/execution changed (
error
return type changed to*Error
). INodeEvaluator
has been removed and got replaced byIEvaluator
. You can change your existing tags/filters by simply replacing the interface.- Two new helper functions:
RenderTemplateFile()
andRenderTemplateString()
. Template.ExecuteRW()
is nowTemplate.ExecuteWriter()
Template.Execute*()
functions do now take apongo2.Context
directly (no pointer anymore).
How you can help
- Write filters / tags (see tutorial) 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
or have a look on gocover.io/github.com/flosch/pongo2) - 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. pongo2 aims to be compatible with it.
You can access pongo2's API documentation on godoc.
Blog post series
- pongo2 v3 released
- pongo2 v2 released
- pongo2 1.0 released [August 8th 2014]
- pongo2 playground [August 1st 2014]
- Release of pongo2 1.0-rc1 + pongo2-addons [July 30th 2014]
- Introduction to pongo2 + migration- and "how to write tags/filters"-tutorial. [June 29th 2014]
Caveats
Filters
- date / time: The
date
andtime
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" }}
isfmt.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 aforce_escape
-filter yet.
Tags
- for: All the
forloop
fields (likeforloop.counter
) are written with a capital letter at the beginning. For example, thecounter
can be accessed byforloop.Counter
and the parentloop byforloop.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 - A web-framework for Go (using pongo2).
- pongo2-tools - Official tools and helpers for pongo2
- 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
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)
// 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"
"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.