webjars-locator-lite

This project provides a means to locate assets within WebJars.

Usage

Get the version of a WebJar on the classpath

new WebJarVersionLocator().version("bootstrap");

Get the full path to a file in a WebJar

new WebJarVersionLocator().fullPath("bootstrap", "js/bootstrap.js");
// returns "META-INF/resources/webjars/bootstrap/<version>/js/bootstrap.js"

Get the path in the standard WebJar classpath location

new WebJarVersionLocator().path("bootstrap", "js/bootstrap.js");
// returns "bootstrap/<version>/js/bootstrap.js"

WebJarVersionLocator has a built-in threadsafe cache that is created on construction. It is highly recommended that you use it as a Singleton to utilize the cache, i.e.

WebJarVersionLocator webJarVersionLocator = new WebJarVersionLocator();
webJarVersionLocator.version("bootstrap"); // cache miss
webJarVersionLocator.version("bootstrap"); // cache hit, avoiding looking up metadata in the classpath

Custom WebJars

By default, webjars-locator-lite only supports WebJars with the Maven group IDs of org.webjars and org.webjars.npm. To support custom WebJars, you can provide a webjars-locator.properties file to register those WebJars with the locator.

The webjars-locator.properties file must be located in META-INF/resources/.

For a WebJar that has its resource files located in META-INF/resources/mywebjar/3.2.1/, the file would look like this:

mywebjar.version=3.2.1

For custom WebJars, it is recommended to package the file within the WebJar.
However, for older releases that do not include this file, it is also possible to add it to your project directly.

Multiple WebJar versions can be defined in a single file:

mywebjar.version=3.2.1
anotherwebjar.version=1.4.3

This allows the use of legacy org.webjars.bower WebJars. However, org.webjars.bowergithub.xyz WebJars are not supported because their resource paths are missing the version part needed for webjars-locator-lite.

You can find an example file in our tests.