https://github.com/neuland/pug4j
a pug implementation written in Java (formerly known as jade)
https://github.com/neuland/pug4j
java template-engine
Last synced: 3 months ago
JSON representation
a pug implementation written in Java (formerly known as jade)
- Host: GitHub
- URL: https://github.com/neuland/pug4j
- Owner: neuland
- License: mit
- Created: 2020-09-18T13:40:55.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2025-08-28T08:06:25.000Z (4 months ago)
- Last Synced: 2025-08-28T14:44:17.852Z (4 months ago)
- Topics: java, template-engine
- Language: Java
- Homepage:
- Size: 2.49 MB
- Stars: 71
- Watchers: 15
- Forks: 14
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- Changelog: History.md
- License: LICENSE
Awesome Lists containing this project
- awesome-java - Pug4j
README
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# pug4j - a pug implementation written in Java
pug4j's intention is to be able to process pug templates in Java without the need of a JavaScript environment, while being **fully compatible** with the original pug syntax.
pug4j was formerly known as jade4j. Because of the naming change of the javascript version and the alignment to the featureset of pug.js (https://pugjs.org/) we decided to switch the name.
## Contents
- [Example](#example)
- [Syntax](#syntax)
- [Usage](#usage)
- [Simple static API](#simple-api)
- [Full API](#api)
- [Caching](#api-caching)
- [Output Formatting](#api-output)
- [Filters](#api-filters)
- [Helpers](#api-helpers)
- [Model Defaults](#api-model-defaults)
- [Template Loader](#api-template-loader)
- [Expressions](#expressions)
- [Reserved Words](#reserved-words)
- [Framework Integrations](#framework-integrations)
- [Breaking Changes in 2.0.0](#breaking-changes-2)
- [Breaking Changes in 1.0.0](#breaking-changes-1)
- [Authors](#authors)
- [License](#license)
## Example
index.pug
```
doctype html
html
head
title= pageName
body
ol#books
for book in books
if book.available
li #{book.name} for #{book.price} €
```
Java model
```java
List books = new ArrayList();
books.add(new Book("The Hitchhiker's Guide to the Galaxy", 5.70, true));
books.add(new Book("Life, the Universe and Everything", 5.60, false));
books.add(new Book("The Restaurant at the End of the Universe", 5.40, true));
Map model = new HashMap();
model.put("books", books);
model.put("pageName", "My Bookshelf");
```
Running the above code through `String html = Pug4J.render("./index.pug", model)` will result in the following output:
```html
My Bookshelf
- The Hitchhiker's Guide to the Galaxy for 5,70 €
- The Restaurant at the End of the Universe for 5,40 €
```
## Syntax
See also the original [https://github.com/pugjs/pug#syntax](https://github.com/pugjs/pug#syntax).
## Usage
### via Maven
Just add following dependency definitions to your `pom.xml`.
```xml
de.neuland-bfi
pug4j
2.4.0
```
### Build it yourself
Clone this repository ...
```bash
git clone https://github.com/neuland/pug4j.git
```
... build it using `maven` ...
```bash
cd pug4j
mvn install
```
... and use the `pug4j-2.x.x.jar` located in your target directory.
Parsing template and generating template in one step.
```java
String html = Pug4J.render("./index.pug", model);
```
If you use this in production you would probably do the template parsing only once per template and call the render method with different models.
```java
PugTemplate template = Pug4J.getTemplate("./index.pug");
String html = Pug4J.render(template, model);
```
Streaming output using a `java.io.Writer`
```java
Pug4J.render(template, model, writer);
```
If you need more control you can instantiate a `PugConfiguration` object.
Pug4J needs a Base path, so that it can determine the parent path. In the simple static API the basePath is empty.
To configure a basePath. You need to use the FileTemplateLoader or ClassPathTemplateLoader and set setBase("").
Example for template location: /root/dir/base/path/index.pug
```java
FileTemplateLoader fileLoader = new FileTemplateLoader("/root/dir/");
fileLoader.setBase("base/path");
PugConfiguration config = new PugConfiguration();
config.setTemplateLoader(fileLoader);
PugTemplate template = config.getTemplate("/index");
Map model = new HashMap();
model.put("company", "neuland");
config.renderTemplate(template, model);
```
Pug is now allowed to read all files below /root/dir/ but not in / and /root.
The `PugConfiguration` handles template caching for you. If you request the same unmodified template twice you'll get the same instance and avoid unnecessary parsing.
```java
PugTemplate t1 = config.getTemplate("index.pug");
PugTemplate t2 = config.getTemplate("index.pug");
t1.equals(t2) // true
```
You can clear the template and expression cache by calling the following:
```java
config.clearCache();
```
For development mode, you can also disable caching completely:
```java
config.setCaching(false);
```
By default, Pug4J produces compressed HTML without unneeded whitespace. You can change this behaviour by enabling PrettyPrint:
```java
config.setPrettyPrint(true);
```
Pug detects if it has to generate (X)HTML or XML code by your specified [doctype](https://github.com/pugjs/pug#syntax).
If you are rendering partial templates that don't include a doctype pug4j generates HTML code. You can also set the `mode` manually:
```
config.setMode(Pug4J.Mode.HTML); //
config.setMode(Pug4J.Mode.XHTML); //
config.setMode(Pug4J.Mode.XML); //
```
Filters allow embedding content like `markdown` into your pug template:
:markdown
# headline
hello **world**
will generate
headline
hello world
pug4j comes with a `plain` and `cdata` filter. `plain` takes your input to pass it directly through, `cdata` wraps your content in ``. You can add your custom filters to your configuration.
config.setFilter("markdown", new MarkdownFilter());
To implement your own filter, you have to implement the `Filter` Interface. If your filter doesn't use any data from the model you can inherit from the abstract `CachingFilter` and also get caching for free. See the [neuland/jade4j-coffeescript-filter](https://github.com/neuland/jade4j-coffeescript-filter) project as an example.
If you need to call custom java functions the easiest way is to create helper classes and put an instance into the model.
```java
public class MathHelper {
public long round(double number) {
return Math.round(number);
}
}
```
```java
model.put("math", new MathHelper());
```
Note: Helpers don't have their own namespace, so you have to be careful not to overwrite them with other variables.
```
p= math.round(1.44)
```
If you are using multiple templates you might have the need for a set of default objects that are available in all templates.
```java
Map defaults = new HashMap();
defaults.put("city", "Bremen");
defaults.put("country", "Germany");
defaults.put("url", new MyUrlHelper());
config.setSharedVariables(defaults);
```
By default, pug4j searches for template files in your work directory. By specifying your own `FileTemplateLoader`, you can alter that behavior. You can also implement the `TemplateLoader` interface to create your own.
```java
TemplateLoader loader = new FileTemplateLoader("/templates/", "UTF-8"); //Defines the path under which all templates are found. You can't include templates from parent directory "/"
loader.setBase("my-maintemplates/"); //the folder where all files starting with "/" are found. This where your main templates are.
config.setTemplateLoader(loader);
```
* '/index' points to '/templates/my-maintemplates/index.pug'
* 'index' points to '/templates/index.pug'
There is also a `ClasspathTemplateLoader` and `ReaderTemplateLoader`.
The original pug implementation uses JavaScript for expression handling in `if`, `unless`, `for`, `case` commands, like this
- var book = {"price": 4.99, "title": "The Book"}
if book.price < 5.50 && !book.soldOut
p.sale special offer: #{book.title}
each author in ["artur", "stefan", "michael","christoph"]
h2= author
### Jexl Expressionhandler (default)
Pug4j uses [JEXL](https://commons.apache.org/proper/commons-jexl/) for parsing and executing these expressions.
JEXL syntax and behavior is very similar to ECMAScript/JavaScript and so closer to the original pug.js implementation. JEXL runs also much faster than GraalVM.
If your template don't relies too much on Javascript-Logic and gets almost everything from the model, this is a good choice.
We are using a slightly modified JEXL version which to have better control of the exception handling. JEXL now runs in a semi-strict mode, where non existing values and properties silently evaluate to `null`/`false` where as invalid method calls lead to a `PugCompilerException`.
#### Reserved Words
JEXL comes with the three builtin functions `new`, `size` and `empty`. For properties with this name the `.` notation does not work, but you can access them with `[]`.
```
- var book = {size: 540}
book.size // does not work
book["size"] // works
```
You can read more about this in the [JEXL documentation](https://commons.apache.org/proper/commons-jexl/reference/syntax.html#Language_Elements).
### GraalVM Expressionhandler (NEW! since 2.0.0 / experimental!)
If you want to use pure javascript expression handling, you can try out the new GraalJS Expression Handler. It supports native javascript expressions but is slower (really slow!) than the Jexl Expression Handler. You can configure it like this:
```java
PugConfiguration config = new PugConfiguration();
config.setExpressionHandler(new GraalJsExpressionHandler());
```
## Framework Integrations
- [neuland/spring-pug4j](https://github.com/neuland/spring-pug4j) pug4j spring integration.
- [vertx-web](https://vertx.io/docs/vertx-web/java/#_jade_template_engine) jade4j for [Vert.X](http://vertx.io/)
## Breaking Changes in 2.0.0
- Classes are renamed to pug4j.
- Default file extension is now .pug
- Compiler Level has been raised to Java 8+
- Syntax has been adapted to the most current pug version. (2.0.4)
- Filter interface changed
- Interpolations not supported in attributes and filters anymore. It now behaves the same way as in pug.js.
### Breaking Changes in 1.3.1
- Fixed a mayor scoping bug in loops. Use this version and not 1.3.0
### Breaking Changes in 1.3.0
- setBasePath has been removed from JadeConfiguration. Set folderPath on FileTemplateLoader instead.
- Scoping of variables in loops changed, so its more in line with jade. This could break your template.
### Breaking Changes in 1.2.0
- Breaking change in filter interface: if you use filters outside of the project, they need to be adapted to new interface
### Breaking Changes in 1.0.0
In Version 1.0.0 we added a lot of features of JadeJs 1.11. There are also some Breaking Changes:
- Instead of 'id = 5' you must use '- var id = 5'
- Instead of 'h1(attributes, class = "test")' you must use 'h1(class= "test")&attributes(attributes)'
- Instead of '!!! 5' you must use 'doctype html'
- Jade Syntax for Conditional Comments is not supported anymore
- Thanks to rzara for contributing to issue-108
- Artur Tomas / [atomiccoder](https://github.com/atomiccoder)
- Stefan Kuper / [planetk](https://github.com/planetk)
- Michael Geers / [naltatis](https://github.com/naltatis)
- Christoph Blömer / [chbloemer](https://github.com/chbloemer)
Special thanks to [TJ Holowaychuk](https://github.com/visionmedia) the creator of jade!
The MIT License
Copyright (C) 2011-2025 [neuland Büro für Informatik](http://www.neuland-bfi.de/), Bremen, Germany
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.