PEAR2 Services_Linkback

Pingback and webmention client and server implementation for PHP 5.3+.

Contents

• Linkback server
  • Glossary
  • Customization via callbacks
    • Services\Linkback\Server\Callback\ITarget
    • Services\Linkback\Server\Callback\ISource
    • Services\Linkback\Server\Callback\ILink
    • Services\Linkback\Server\Callback\IStorage
    • TODO
• Linkback client
• Installation
• About Services_Linkback

Linkback server

The package provides a basic pingback+webmention server implementation that can be customized easily via callbacks.

Usage:

$srv = new \PEAR2\Services\Linkback\Server();
$srv->addCallback(new PingbackLogger());
$srv->run();

Glossary

source URL

Remote URL that links to the local target URL

target URL

Local URL that gets linked by the source URL

Customization via callbacks

The server provides 4 types of callbacks to modify its behaviour. Each callback needs to implement one of the four interfaces:

Services\Linkback\Server\Callback\ITarget

Verifies that the target URL exists in the local system. Useful to filter out pingbacks for non-existant URLs.

FIXME: Default implementation

Services\Linkback\Server\Callback\ISource

Fetches the source URL for further verification. Used to determine if the source URL really exists.

Services_Pingback provides the Services\Linkback\Server\Callback\FetchSource callback class that is automatically registered with the server.

Services\Linkback\Server\Callback\ILink

Verifies that the source URL content really links to the target URL. Used to filter out fake pingbacks that do not actually provide links.

Services_Pingback provides the Services\Linkback\Server\Callback\LinkExists callback class that is automatically registered with the server.

Services\Linkback\Server\Callback\IStorage

After all verifications have been done, the storage finally handles the pingback - it could e.g. log it to a file or a database.

Services_Pingback does not provide a default storage implementation; you have to write it yourself.

TODO

See what we can learn from http://www.acunetix.com/blog/web-security-zone/wordpress-pingback-vulnerability/

Linkback client

Tell someone that you linked to him:

$from = 'http://my-blog.example.org/somepost.html';
$to   = 'http://b.example.org/inspiration.html';
$lbc  = new \PEAR2\Services\Linkback\Client();
$lbc->send($from, $to);

You can adjust the HTTP_Request2 settings:

$req = $lbc->getRequest();
$req->setConfig(
    array(
        'ssl_verify_peer' => false,
        'ssl_verify_host' => false
    )
);
$lbc->setRequestTemplate($req);

And change the user agent header sent with the linkback requests:

$req = $lbc->getRequest();
$headers = $req->getHeaders();
$req->setHeader('user-agent', 'my blog engine');
$lbc->setRequestTemplate($req);

And a debug mode is available, too:

$lbc->setDebug(true);

This setting stores HTTP responses for later inspection.

Installation

Using composer:

$ composer require pear2/services_linkback

About Services_Linkback

Services_Linkback was written by Christian Weiske and is licensed under the LGPLv3 or later.

Homepage

http://pear2.php.net/PEAR2_Services_Linkback

Bug tracker

https://github.com/pear2/Services_Linkback/issues

Documentation

The examples/ folder.

Packagist

https://packagist.org/packages/pear2/services_linkback

Unit test status

https://travis-ci.org/pear2/Services_Linkback