Web Bundles
This is a Node.js module for serializing and parsing the application/webbundle
format defined in the
Web Bundles
draft spec.
Installation
Using npm:
npm install wbnUsage
Please be aware that the API is not yet stable and is subject to change any time.
Creating a Bundle:
import * as fs from 'fs';
import * as wbn from 'wbn';
const builder = new wbn.BundleBuilder();
builder.addExchange(
'https://example.com/', // URL
200, // response code
{ 'Content-Type': 'text/html' }, // response headers
'<html>Hello, Web Bundle!</html>' // response body (string or Uint8Array)
);
builder.setPrimaryURL('https://example.com/'); // entry point URL
fs.writeFileSync('out.wbn', builder.createBundle());Reading a Bundle:
import * as fs from 'fs';
import * as wbn from 'wbn';
const buf = fs.readFileSync('out.wbn');
const bundle = new wbn.Bundle(buf);
const exchanges = [];
for (const url of bundle.urls) {
const resp = bundle.getResponse(url);
exchanges.push({
url,
status: resp.status,
headers: resp.headers,
body: new TextDecoder('utf-8').decode(resp.body),
});
}
console.log(
JSON.stringify(
{
version: bundle.version, // format version
exchanges,
},
null,
2
)
);CLI
This package also includes wbn command which lets you build a web bundle from
a local directory. For example, if you have all the necessary files for
https://example.com/ in static/ directory, run the following command:
$ wbn --dir static \
--baseURL https://example.com/ \
--output out.wbnRun wbn --help for full options.
Note: currently this CLI only covers a subset of the functionality offered by
gen-bundle
Go tool.
Backwards compatibility
This module supports creating and parsing Web Bundles that follow different draft versions of the format specification. In particular:
- version
b2follows the latest version of the Web Bundles spec (default) - version
b1follows the previous version of the Web Bundles spec
To create a new bundle with the b1 format, pass the version value to the
constructor:
const builder = (new wbn.BundleBuilder('b1'))
.setPrimaryURL('https://example.com/')
.setManifestURL('https://example.com/manifest.json')
.addExchange(...);
fs.writeFileSync('out_b1.wbn', builder.createBundle());Likewise, the wbn command can optionally take a --formatVersion b1 parameter
when creating a new Web Bundle.
This module also takes care of selecting the right format version automatically
when reading a bundle. Check the property bundle.version to know the decoded
bundle's format version.
Using Bundles
Generated bundles can be opened with web browsers supporting web bundles.
Chrome (79+) experimentally supports navigation to Web Bundles with some limitations. See this document for more details.
Chrome (104+) supports
<script type=webbundle>.
Release Notes
0.0.9
- Add support for overriding headers.
0.0.8
- Now
wbnpackage provides both ES modules and CommonJS exports. - Dependency on the Node.js API has been removed from the
wbnmodule, making it easier to use the module in browsers.
0.0.7
- Now BundleBuilder accepts relative resource URLs. Relative URLs can be used in
<script type=webbundle>where relative URLs are resolved using the bundle's URL as base URL.
0.0.6
- Now BundleBuilder generates bundles of format
b2by default. See Backwards compatibility section above.