node-get-webmention-url

Retrieve a Webmention endpoint from a given URL.

Originally written because I kept finding bugs in lookup-webmention-server but the implementation was waaaay overcomplicated and it took me forever to fix anything. Also it seemed unmaintained.

The tests and API were, however, stolen directly from that project. And for that, I am indebted to @connrs. So thank you!

Install

npm install get-webmention-url

Usage

This module is a drop-in replacement for lookup-webmention-server except that if it encounters a relative URL in a Webmention <link> relation, it will resolve the URL to an absolute URL. Also it supports more discovery mechanisms.

Specifically, the module exports a single function. Said function takes two arguments, a URL string or an object and a callback. If an error is encountered, the callback is invoked with it as the first parameter. Otherwise, the Webmention endpoint (if found) will be passed as the second parameter to the callback.

If you pass an object as the first parameter, you have two options: it can either be an object as returned by require('url').parse, or an object with a url key. In either case, you can additionally pass the ua key to set the User-Agent that the library will use.

Only problems during HTTP requests are considered errors for the purposes of callback invocation. Failure to find a valid Webmention endpoint is not considered an error - you'll just get undefined as the second callback parameter.

Example

var lookup = require('get-webmention-url');

lookup('https://example.com/index.html', function(err, url) {
	if (err) throw err;
	console.log(url);
});

var lookup = require('get-webmention-url'),
    url = require('url');

lookup(url.parse('https://example.com/index.html'), function(err, url) {
	if (err) throw err;
	console.log(url);
});

var lookup = require('get-webmention-url');

lookup({url: 'https://example.com/index.html', ua: 'foobar/1.0.0'}, function(err, url) {
	if (err) throw err;
	console.log(url);
});

Security considerations

This module does not do anything to address the Webmention spec's security considerations section. You need to take care of this yourself.

Version support

Supports Node 4+.

Author

AJ Jordan alex@strugee.net

License

Lesser GPL 3.0+, except for the tests which were stolen from @connrs and so are BSD 3-clause