zegnat/webmention-endpoint-discovery

A straight forward implementation of webmention endpoint discovery.

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Package info

github.com/Zegnat/php-webmention-endpoint-discovery

pkg:composer/zegnat/webmention-endpoint-discovery

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Installs: 11

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Suggesters: 0

Stars: 2

Open Issues: 0

v1.1 2026-08-05 13:41 UTC

This package is auto-updated.

Last update: 2026-08-05 13:50:36 UTC


README

Mostly a thought experiment to see what exactly is required to do Webmention endpoints discovery. You can use this implementation on its own, though it will probably net you better results to tightly integrate the code within the rest of your application.

Under the licence of this project you should feel free to copy any parts of it that you want to take for inspiration! Not even attribution is required – even when appreciated.

Install

Via Composer

$ composer require zegnat/webmention-endpoint-discovery

Usage

$discoverer = new Zegnat\Webmention\EndpointDiscovery($httpClient, $requestFactory);
echo $discoverer->discover('https://webmention.rocks/test/1');
// https://webmention.rocks/test/1/webmention?head=true
  • $httpClient must be an HTTP client implementing ClientInterface as defined by PSR-18. Clients implementing HttpClient as defined by HTTPlug 1.x are also still accepted.
  • $requestFactory must be an implementation of RequestFactoryInterface as defined by PHP-FIG as PSR-17.

Secure Endpoints

NOTE: This feature is very much experimental. Please consult the code before deciding to use it.

There might be some weird issues triggered by having Webmention senders post mentions to things on their local machines. The Webmention specification calls on senders to avoid sending Webmentions to localhost. This library enables that.

EndpointDiscovery::secureDiscover will return null not only when no endpoint could be found, but also when the found endpoint’s host’s DNS resolves to an IP address in the private or reserved range. When all the IP addresses found are deemed to be OK, the method will return an array as follows:

$discoverer = new Zegnat\Webmention\EndpointDiscovery($httpClient, $requestFactory);
var_export($discoverer->secureDiscover('https://webmention.rocks/test/1'));
// array (
//   'url' => 'https://webmention.rocks/test/1/webmention?head=true',
//   'host' => 'webmention.rocks',
//   'ips' =>
//   array (
//     0 => '173.230.155.197',
//   ),
// )

It is recommended that the Webmention sender uses this information for posting the mention. Use one of the checked IP addresses to post to (instead of the domain, which might redo the DNS lookup) with the host in a Host HTTP header.

Supported PHP versions

This library requires PHP 7.0 or newer and is tested against PHP 7.0, 7.1, 7.2, 7.3, 7.4, 8.0, 8.1, 8.2, 8.3, 8.4 and 8.5.

Testing

Tests run on every supported PHP version through Docker, orchestrated by Castor. Each PHP version and its dependencies live entirely in their container, so only Docker and Castor are needed on the host:

$ castor matrix     # run the whole matrix
$ castor test 8.4   # run a single version
$ castor coverage   # run with code coverage and enforce the minimum

The tests that make live calls to Webmention Rocks! are marked with @group internet. Pass --offline to castor test or castor matrix to exclude them:

$ castor test 8.4 --offline

The hash-named test fixtures under tests/responses are verbatim captures of Webmention Rocks! responses under its license; see CREDITS.md for their source and the LICENSES directory (REUSE).

License

The BSD Zero Clause License (0BSD). Please see the LICENSE file for more information.