FigDice / Discussion / General Discussion: How to use Feeds and implement Factories

Hi Martin,

Thank you for your comments.

Below is an example of how to use the Factory pattern with Feeds in FigDice.
Suppose that you want to render this View:

File: myView.xml

<html>
  <body>
    <fig:feed class="MyFeed" target="myfeed" />
    <div fig:text="/myfeed/mydata" />
  </body>
</html>

Let's consider that your Feed class MyFeed must read data from a database.

Feed class

First, your Feed class must have a public method which enables the injection of the Database object (PDO, direct credentials, mysqli resource: it can be anything you want, depending on the way you code your DB interactions). The Feed instance will just assume that this has been prepared beforehand, from outside.

File: MyFeed.php

<?php
class MyFeed extends FIG_Feed {

  public function setDatabase($database) {
    $this->db = $database;
  }

  public function run() {
    //This is the method that the framework calls
    //when it needs to execute your Feed class in
    //order to inject its outcome into the View's universe.
    //At this time, you can safely assume that the
    // setDatabase( ) method
    //has been called already, and that your
    // $this->db attribute
    //is populated.

    //To fetch the data from your database, you will use,
    // depending on your project:

    /*either*/ $this->db->query("some sql string");
    /*or*/     mysqli_query("some sql string", $this->db);

    //and so on.
  }
}

Feed Factory

Now, you will tell your FIG_View how to instantiate MyFeed on demand:
you do this through a Feed Factory.

File: MyDatabaseAwareFeedFactory.php

<?php
class MyDatabaseAwareFeedFactory implements FIG_FeedFactory {
  public function create ( /*string*/ $className, array $attributes ) {

    //Your Factory can be responsible for several
    // Feed classes, based on their names
    if ( 'MyFeed' == $className ) {
      $feed = new MyFeed();
      $feed->setDatabase( /* everything you need to make 
        the Feed class aware of the DB */ 
      );
      return $feed;
    }

    //Your factory should serve in the same way
    //the instances of various Feed class
    //which belong to a same family (e.g. Feeds that
    //read data from one same database).

    //If your Factory class was requested a Feed
    // which it does not know to handle:
    return null;
  }

  //You call this method yourself, in your controller,
  //before passing this Factory to the View.
  //By this method you make your Factory keep track
  //of the Database, so as to make it possible to
  //propagate it to the future Feed instances that
  //this Factory will create.
  public function setDatabase( ... ) {
    ...
  }
}

Controller

Finally, your controller (which owns the main access to database) will invoke the view after registering the Feed Factory.
The Feed Factory is given access to DB through your special method, and in turn it will be able to pass it the the feeds later.

<?php

$feedFactory = new MyDatabaseAwareFeedFactory();
$feedFactory->setDatabase( /* your db link, or PDO object, etc. */ );

$view = new FIG_View();
$view->registerFeedFactory( $feedFactory );

// and continue normally with the View
// in particular:
// - load the XML source,
// - register more Feed Factories
// - register custom function factories
// - set the output Language of the view, and
//   indicate the path for internationalization files,
// - and finally ->render() the view.

I hope this helps!

Regards,
Gabriel

Last edit: Gabriel Zerbib 2013-03-25

How to use Feeds and implement Factories

PHP Templating System

Forums

Help

How to use Feeds and implement Factories

Feed class

Feed Factory

Controller

How to use Feeds and implement Factories

PHP Templating System

Forums

Help

How to use Feeds and implement Factories document.SUBSCRIPTION_OPTIONS = { "thing": "topic", "subscribed": false, "url": "subscribe", "icon": { "css": "fa fa-envelope-o" } };

Feed class

Feed Factory

Controller

How to use Feeds and implement Factories