HOWTO: Displaying Blogger feeds with PHP

This HOWTO is going to follow the basic structure of the Python one.

To start out you'll have to grab the Zend Google data Client Library and then set the include_path so you can use it

ini_set("include_path", ".:../:./include:../include:/home/gpowered/webapps/php/includes/ZendGdata-1.0.1/library");

We then import the parts the we'll need:

require_once 'Zend/Loader.php';
Zend_Loader::loadClass('Zend_Gdata');
Zend_Loader::loadClass('Zend_Gdata_Query');
Zend_Loader::loadClass('Zend_Gdata_ClientLogin');

One of the first things we're going to have to do is authenticate with google services. There are two ways to do this: AuthSub proxy authentication which has a user login using their own credentials, and ClientLogin username/password au thentication where you send a username and password. We will be using ClientLogin. I built a small class called gPoweredBlogger to hold the different parts I will need for this example.

class gPoweredBlogger{
    private $user;// = 'timothy.broder';
    private $pass;// = '**************';
    private $service;// = 'blogger';

    private $blog_id;// = '413573351281770670';
    private $uri;// = "http://www.blogger.com/feeds/" . $blog_id . "/posts/default";
    private $show_num;// = 5;

    private $client;// = Zend_Gdata_ClientLogin::getHttpClient($user, $pass, $service);
    private $gdClient;// = new Zend_Gdata($client);
    private $query;// = new Zend_Gdata_Query($uri);

    private $total_posts;

    public $output;

Then we start setting up our call to the service.

public function __construct($user, $pass, $blog_id){
    $this->user = $user;
    $this->pass = $pass;
    $this->service = 'blogger';

    $this->blog_id = $blog_id;
    $this->uri = "http://www.blogger.com/feeds/" . $this->blog_id . "/posts/default";
    $this->show_num = 5;

    $this->client = Zend_Gdata_ClientLogin::getHttpClient($this->user, $this->pass, $this->service);
    $this->gdClient = new Zend_Gdata($this->client);
    $this->query = new Zend_Gdata_Query($this->uri);
    $this->total_posts = $this->get_total($this->query);
}

For more info see the blogger developer's guide with php or the Google Account Authentication documentation
After we have authenticated with Google we need to start building up our query to GData. The first thing you'll need is your blog's id.
You can use the function in the dev guide to help you with this if you don't already know it.
Like the Python version, the below function returns the total number of posts that are in the feed. We can get a small response by sending 0 for the max results. Below is the function and the small response we get from it.

private function get_total($query){
    //query for no posts
    $this->query->setParam('max-results', '0');
    $this->query->setParam('start-index', '1');

    //get back entryless feed
    $feed = $this->gdClient->getFeed($this->query);
    return $feed->totalResults->text;
}

<ns0:feed xmlns:ns0="http://www.w3.org/2005/Atom">
<ns1:totalresults xmlns:ns1="http://a9.com/-/spec/opensearchrss/1.0/">5</ns1:totalresults>
<ns1:itemsperpage xmlns:ns1="http://a9.com/-/spec/opensearchrss/1.0/">0</ns1:itemsperpage>
<ns1:startindex xmlns:ns1="http://a9.com/-/spec/opensearchrss/1.0/">1</ns1:startindex>
<ns0:generator uri="http://www.blogger.com" version="7.00">Blogger</ns0:generator>
<ns0:author><ns0:name>Tim</ns0:name></ns0:author>
<ns0:id>tag:blogger.com,1999:blog-413573351281770670</ns0:id>
<ns0:link href="https://gpowered.blogspot.com/" rel="alternate" type="text/html" />
<ns0:link href="https://gpowered.blogspot.com/feeds/posts/default" rel="http://schemas.google.com/g/2005#feed" type="application/atom+xml" />
<ns0:link href="http://www.blogger.com/feeds/413573351281770670/posts/default?max-results=0" rel="self" type="application/atom+xml" />
<ns0:link href="http://www.blogger.com/feeds/413573351281770670/posts/default" rel="http://schemas.google.com/g/2005#post" type="application/atom+xml" />
<ns0:title type="text">gPowered</ns0:title>
<ns0:updated>2007-07-18T10:55:06.728-05:00</ns0:updated>
</ns0:feed>

So we get the total number of posts and then we can start pulling data. Lets make a generic function, PostFrom, that can be used to show multiple posts, or just single ones, depending on what you pass to it. The start number that is passed to PostFrom has been set to the first post in the blog is considered to have an id of 1 and the latest post is the same as total_posts. This is useful so if viewers want to bookmark the page they are looking at, the post that is being displayed will not change. The following are the different functions that will make use of it.

//show latest posts
public function Posts(){
    return $this->ListPosts($this->total_posts);
}

//show posts starting from a certain point
public function ListPosts($start){
    $start = $this->total_posts - $start + 1;
    return $this->PostFrom($start, $this->show_num);
}

//show a single post
public function Post($start){
    $start = $this->total_posts - $start + 1;
    return PostFrom($start, 1);
}

//show count number of posts starting from a certain point
private function PostFrom($start, $count){
    //query for count number of posts starting at the given post
    $this->query->setParam('max-results', $count);
    $this->query->setParam('start-index', $start);
    $feed = $this->gdClient->getFeed($this->query);

Now we have all the data we need in the feed variable. Its been turned into an object so we don't have to worry about XML parsing here. Every node has become an objects and lists. Objects for single nodes(title), and lists for where there are multiple nodes of the same name (entry, link)

//for links
$curr_id = $this->total_posts - $start + 1;

//normalize data for output
foreach($feed->entries as $entry){
    //id for links
    $entry->my_id = $curr_id;
    $curr_id -= 1;
}

Of course we're going to need next and previous buttons as well. The way we've set up the math with total_posts and the start number, we only have to increment or decrement these by count (the number of posts to display on a page). I also set part of the link, as well as the page title, that I will use below in the HTML.

$prev = $this->total_posts - ($start - $count) + 1;
if($prev > $total_posts){
    $prev = null;
}


$next = $this->total_posts - ($start + $count) + 1;
if($next < 1){
    $next = null;
}

//showing single post
if(count == 1){
    $link = 'post';
    $title = $feed->entries[0]->title->text;
    //listing posts
}
else{
    $link = 'posts';
    $title = 'home';
}

The final part is to make a quick object that we can use in the HTML to output everything

        $this->output = new Output($feed->entries, $title, $prev, $next, $link);
    }
}

class Output{
    public $entries;
    public $title;
    public $prev;
    public $next;
    public $link;
    public function __construct($entries, $title, $prev, $next, $link){
        $this->entries=$entries;
        $this->title=$title;
        $this->prev=$prev;
        $this->next=$next;
        $this->link=$link;
    }
}

To the HTML!

The first part consists of displaying the post itself, along with its relevant information. So lets built up our objects

$blog = new gPoweredBlogger('timothy.broder', '*************', '413573351281770670');
$blog->Posts();

$output = $blog->output;

Below all the php we can run through out output object and display the posts

<? foreach($output->entries as $entry){ ?>
     <h2><a href="/post/<? echo $entry->my_id ?>"><? echo $entry->title->text ?></h2></a>
     <? echo $entry->content->text;
     $datetime = strtotime(substr($entry->published, 0, 10) . ' ' . substr($entry->published, 11, 8 ));
     ?>
     <p>Posted by <? echo $entry->author[0]->name->text ?> on <? echo date("m/d/Y",$datetime) ?> at <? echo date("g:i a",$datetime) ?></p>

      <div id="divider"></div>
      <?}?>

That's all for now. A working example is here