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.
With the addition of a new GraalJsExpressionHandler your code can be more compatible to the js version than before.
- Example
- Syntax
- Usage
- Simple static API
- Full API
- Expressions
- Reserved Words
- Framework Integrations
- Breaking Changes in 2.0.0
- Breaking Changes in 1.0.0
- Authors
- License
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
List<Book> books = new ArrayList<Book>();
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<String, Object> model = new HashMap<String, Object>();
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:
<!DOCTYPE html>
<html>
<head>
<title>My Bookshelf</title>
</head>
<body>
<ol id="books">
<li>The Hitchhiker's Guide to the Galaxy for 5,70 €</li>
<li>The Restaurant at the End of the Universe for 5,40 €</li>
</ol>
</body>
</html>See also the original https://github.com/pugjs/pug#syntax.
Just add following dependency definitions to your pom.xml.
<dependency>
<groupId>de.neuland-bfi</groupId>
<artifactId>pug4j</artifactId>
<version>2.2.0</version>
</dependency>Clone this repository ...
git clone https://github.com/neuland/pug4j.git... build it using maven ...
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.
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.
PugTemplate template = Pug4J.getTemplate("./index.pug");
String html = Pug4J.render(template, model);Streaming output using a java.io.Writer
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
FileTemplateLoader fileLoader = new FileTemplateLoader("/root/dir/");
fileLoader.setBase("base/path");
PugConfiguration config = new PugConfiguration();
config.setTemplateLoader(fileLoader);
PugTemplate template = config.getTemplate("index");
Map<String, Object> model = new HashMap<String, Object>();
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.
PugTemplate t1 = config.getTemplate("index.pug");
PugTemplate t2 = config.getTemplate("index.pug");
t1.equals(t2) // trueYou can clear the template and expression cache by calling the following:
config.clearCache();For development mode, you can also disable caching completely:
config.setCaching(false);By default, Pug4J produces compressed HTML without unneeded whitespace. You can change this behaviour by enabling PrettyPrint:
config.setPrettyPrint(true);Pug detects if it has to generate (X)HTML or XML code by your specified doctype.
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); // <input checked>
config.setMode(Pug4J.Mode.XHTML); // <input checked="true" />
config.setMode(Pug4J.Mode.XML); // <input checked="true"></input>
Filters allow embedding content like markdown into your pug template:
:markdown
# headline
hello **world**
will generate
<h1>headline</h1>
<p>hello <strong>world</strong></p>
pug4j comes with a plain and cdata filter. plain takes your input to pass it directly through, cdata wraps your content in <![CDATA[...]]>. 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 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.
public class MathHelper {
public long round(double number) {
return Math.round(number);
}
}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.
Map<String, Object> defaults = new HashMap<String, Object>();
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.
TemplateLoader loader = new FileTemplateLoader("/templates/", "UTF-8");
config.setTemplateLoader(loader);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
Pug4j uses 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.
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.
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 than the Jexl Expression Handler. You can configure it like this:
PugConfiguration config = new PugConfiguration();
config.setExpressionHandler(new GraalJsExpressionHandler())- neuland/spring-pug4j pug4j spring integration.
- vertx-web jade4j for Vert.X
- 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.
- Fixed a mayor scoping bug in loops. Use this version and not 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 change in filter interface: if you use filters outside of the project, they need to be adapted to new interface
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
- Stefan Kuper / planetk
- Michael Geers / naltatis
- Christoph Blömer / chbloemer
Special thanks to TJ Holowaychuk the creator of jade!
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