Client library for sending webmention and pingback notifications.

Given one of your source URLs, this function will find links on the page, discover the webmention and pingback endpoints for each, and send mentions for any it discovers.

<?php
$client = new IndieWeb\MentionClient();
$sent = $client->sendMentions($sourceURL);

echo "Sent $sent mentions\n";
?>

The library will fetch the source URL, parse it, and look for the first h-entry, h-card or h-event. It will then attempt to send webmentions (and pingbacks) to all URLs found in the object, as either properties or inside the "content" HTML.

The library attempts to find the endpoints by doing a HEAD request to the target URL and looking at the headers, and if none are found, then it makes a GET request and searches the body of the page for the rel values.

After finding either pingback or webmention endpoints, the request is sent to each.

Alternatively, you can pass in HTML as the second parameter and the library will look for ALL absolute links in the HTML instead of fetching your post contents and looking for the microformats object.

<?php
$client = new IndieWeb\MentionClient();
$sent = $client->sendMentions($sourceURL, $sourceHTML);

echo "Sent $sent mentions\n";
?>

Given a target URL, this function will return its webmention endpoint if found, otherwise it will return false.

<?php
$client = new IndieWeb\MentionClient();
$endpoint = $client->discoverWebmentionEndpoint($targetURL);
$endpoint = $client->discoverPingbackEndpoint($targetURL);
?>

To send a webmention to a target URL, you can use the function below. This will first discover the webmention endpoint of the target, and if found, will then send the webmention payload to it. You can pass an additional parameter to include other properties in the payload.

<?php
$client = new IndieWeb\MentionClient();
$response = $client->sendWebmention($sourceURL, $targetURL);
$response = $client->sendWebmention($sourceURL, $targetURL, ['vouch'=>$vouch]);
?>

If no webmention endpoint was found at the target, the function will return false. See the function below for an example of the response when the webmention is successful.

You can also check if the endpoint advertises a webmention endpoint before trying to send one:

<?php
$client = new IndieWeb\MentionClient();
$supportsWebmention = $client->discoverWebmentionEndpoint($targetURL);
if($supportsWebmention) {
  $client->sendWebmention($sourceURL, $targetURL);
}
?>

<?php
$client = new IndieWeb\MentionClient();
$response = $client->sendPingback($sourceURL, $targetURL);
?>

You can also check if the endpoint advertises a pingback endpoint before trying to send one:

<?php
$client = new IndieWeb\MentionClient();
$supportsPingback = $client->discoverPingbackEndpoint($targetURL);
if($supportsPingback) {
  $client->sendPingback($sourceURL, $targetURL);
}
?>

To send the actual webmention or pingback payload, you can use the static functions below. You can pass additional properties for the webmention request in an array if needed.

<?php
$response = IndieWeb\MentionClient::sendWebmentionToEndpoint($endpoint, $source, $target);
$response = IndieWeb\MentionClient::sendWebmentionToEndpoint($endpoint, $source, $target, ['vouch'=>$vouch]);
?>

The response is an array containing the HTTP status code, HTTP headers, and the response body:

{
  "code": 202,
  "headers": {
    "Content-Type: text/plain"
  },
  "body": "Webmention is processing"
}

You can check if the webmention was accepted by testing if the response code is 200, 201 or 202.

<?php
$success = IndieWeb\MentionClient::sendPingbackToEndpoint($endpoint, $source, $target);
?>

The pingback function returns true or false depending on whether the pingback was successfully sent.

If you have a rendered HTML page (or partial HTML page), you can use this function to return a list of outgoing links found on the page.

<?php
$client = new IndieWeb\MentionClient();
$urls = $client->findOutgoingLinks($html);
?>

Alternately, you can pass a parsed Microformats object to the findOutgoingLinks function and it will search for URLs in any property as well as in the HTML of any e-content objects.

$client = new IndieWeb\MentionClient();
$parsed = \Mf2\parse($html, $sourceURL);
$urls = $client->findOutgoingLinks($parsed);

All links found will be returned an array, with duplicate URLs removed. If no links are found, it will return an empty array.

[
  "http://example.com/1",
  "http://example.com/2"
]

If you want to collect debugging information so you can see the steps the library is doing, run IndieWeb\MentionClient::enableDebug(); before calling any other function.

To learn more about Webmention, see webmention.net.

The webmention.io service can also act as a pingback->webmention proxy which will allow you to accept pingbacks as if they were sent as webmentions.

If you want to accept pingbacks on your site, check out webmention.io which handles accepting the XMLRPC request and exposes the data via an API.

Copyright 2013 by Aaron Parecki

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.