So, here’s a plugin that implements a basic Known to Known cross poster, which uses the Known API authenticated with OAuth2 using my OAuth2 server.

This post will let you link an account on one Known server with an account on another Known server, and allow you to crosspost status and text posts from one to the other.

Primarily this is a demo of OAuth together with the Known API, but it might be handy if you have, say, a corporate blog but still want to post to it from your main site.

Pull it apart, play with the OAuth and see how I talk to the API!

» Visit the project on Github...

OAuth is a technology that allows a user to connect a client to a service, but without that user needing to enter their password.

The usual way this works is that a user clicks on a button, and are taken to a page asking whether they wish to allow the connection. Under the bonnet a handshake is going on between the client and server, resulting in an exchange of tokens.

If you’ve ever used the “Facebook connect” or “Sign in with twitter” buttons, you are likely familiar with this.

Known has a comprehensive API, and while it is possible to authenticate yourself to it using signed HTTP headers, I thought it’d be handy to be able to authenticate with OAuth as well (it was an excuse for me to write the code powering the server side of an OAuth exchange, a good way to understand it!).

The plugin I wrote lets a user manage “applications” – collections of keys – which can be used by an OAuth2 client to power an exchange.

Example Usage

Here is an example of client authentication in it’s most basic…

To get a code:

https://mysite.com/oauth2/authorise/?response_type=code&client_id=<your API Key>&redirect_uri=<path to your endpoint>

You will be directed to a log in page, followed by a confirmation page as necessary, after which you will get a response code back. This response will either be a JSON encoded blob, or if you specified a redirect_uri, the values will be forwarded as get variables.

Exchanging the code for a token

https://mysite.com/oauth2/access_token/?grant_type=authorization_code&client_id=<your API Key>&redirect_uri=<path to your endpoint>

You should get back a json encoded blob with an access token, expiry and refresh token.

Once you’ve performed an OAuth exchange, you will be provided with an access token. You can pass this token along with any web service API call to authenticate your request.

» Visit the project on Github...

There are now many plugins for Known, a lot of them I’ve written, are available on Github.

Many people, myself included, like to install these plugins via a git submodule checkout – this simplifies deployment and makes updating installed plugins easier, however it can be problematic.

The problem is that either the repository contains the actual plugin in a subdirectory (e.g. my Github plugin is in the repo ‘KnownGithub‘, and the plugin is in a subdirectory ‘Github’), or if they don’t, the actual clone of the repository will default to an incompatible name (e.g. Known’s Facebook plugin is in a repo ‘facebook’, but the code wants it in a directory ‘Facebook’).

Both have their own issues, but both mean you can’t directly use them in a submodule git checkout (unless you use my symlink trick). It would be nice if you could use these repos directly, so I put together a patch (which has been accepted) that allows you to build your plugin repos in such a way that they can be used directly from a git clone.

Introducing the autoloader

The patch I submitted introduces the ability to provide a loader for your plugin in the root directory of your plugin repository. So, if your plugin is Foo in a directory inside your repository KnownFoo, you could create a special autoloader.php file in the root that will allow Known to load your plugin in the normal way, direct from a git clone into your IdnoPlugins directory.

To do this, create a file autoloader.php with the following code:

/**
 * Support loading of direct checkout.
 */
spl_autoload_register(function($class) {
        $class = str_replace('\\', DIRECTORY_SEPARATOR, $class);

    $segments = explode(DIRECTORY_SEPARATOR, $class);
    $PLUGIN_NAME = $segments[1];

        $basedir = dirname(dirname(dirname(__FILE__))) . '/'; 
        $file = str_replace($PLUGIN_NAME, basename(dirname(__FILE__)) . "/$PLUGIN_NAME", $class);

    \Idno\Core\site()->plugins()->plugins[basename(dirname(__FILE__))] = \Idno\Core\site()->plugins()->plugins[$PLUGIN_NAME];
    unset(\Idno\Core\site()->plugins()->plugins[$PLUGIN_NAME]);

        if (file_exists($basedir . $file . '.php')) {
                include_once($basedir . $file . '.php');
        }

});

This code will automatically load your plugin classes from its “real name” subdirectory, and make it available to your plugin loader.

Have a look at my Github plugin for an example, have fun!