Recently I though of making one combines RSS feed of both of my blogs and my twitter updates. There are some RSS merging services out there, and there’s also Yahoo pipes which seems that it’s most useful ability is to do various RSS tweaking tasks. As part of my playing around with the Zend Framework, I’ve decided to make this merged RSS feed using the Zend_Feed component. Actually at the end I’ve realized that this merged feed idea is quite useless, but at least this post came out of it

Most of the basic actions, like importing an RSS feed, creating an RSS feed and more are covered in the Zend Framework manual. In this post I will elaborate more on the more advanced topics, like sorting and merging RSS feeds but I will also go briefly over the more basic stuff as well.

So let’s begin.

First of all we need to load the RSS feed, this is being done quite easily:

   1: function loadFeed ($url) {

   2:     try {

   3:         $feed = Zend_Feed::import($url);

   4:     } catch (Zend_Feed_Exception $e) {

   5:         // feed import failed

   6:         return null;

   7:     }

   8:     return $feed;    

   9: }

Now that we have a feed we can read its properties, for example let’s print out the title:

   1: $feed = loadFeed ('http://www.arikfr.com/blog/feed/');

   2: echo $feed->title();

Or iterate over all of the feed entries and print their titles:

   1: foreach ($feed as $entry) {

   2:     echo $entry->title();

   3: }

(the Zend_Feed_Abstract, which both the Zend_Feed_Rss and Zend_Feed_Atom implement, is implementing the Iterator interface so we can use it in an foreach loop).

Now that we covered the basics let’s start constructing a new feed. You can make an RSS or Atom feed using Zend_Feed. We will create an RSS feed. Creating the feed is being done by constructing an array that will hold the new feed properties. There are mandatory fields and some optional fields. In this example I will cover all the mandatory ones (you can find the complete structure here):

   1: $merged_feed = array (

   2:     'title'     => 'ArikFr.com merged Feed',

   3:     'link'         => 'http://www.arikfr.com/merged_feed.php',

   4:     'charset'   => 'UTF-8', 

   5:     'entries'     => array (),

   6:     );

I’m leaving the entries field empty, and we will fill it later with entries from the feeds we want to merge. Now that we have the basic array read , we can create a Zend_Feed_Rss object from it:

   1: $rssFeedFromArray = Zend_Feed::importArray($merged_feed, 'rss');

And we can output it to the browser simple by calling the send method of the Zend_Feed_Rss object:

   1: $rssFeedFromArray->send();

Now all the browser will get is an empty RSS feed:

   1: <?xml version="1.0" encoding="UTF-8"?>

   2: <rss xmlns:content="http://purl.org/rss/1.0/modules/content/" version="2.0">

   3:   <channel>

   4:     <title><![CDATA[ArikFr.com merged Feed]]></title>

   5:     <link>http://www.arikfr.com/merged_feed.php</link>

   6:     <description></description>

   7:     <pubDate>Mon, 25 Feb 2008 20:55:37 +0000</pubDate>

   8:     <generator>Zend_Feed</generator>

   9:     <docs>http://blogs.law.harvard.edu/tech/rss</docs>

  10:   </channel>

  11: </rss>

By now all we have done was quite simple and very basic. Now let’s start importing the entries from the feeds we want to merge:

   1: function getEntriesAsArray ($feed) {

   2:     $entries = array();

   3:     

   4:     foreach ($feed as $entry) {    

   5:         $entries[] = array (

   6:             'title' => $entry->title(),

   7:             'link' => $entry->link(),

   8:             'guid' => $entry->guid(),

   9:             'lastUpdate' =>strtotime($entry->pubDate()),

  10:             'description' => $entry->description(),

  11:             'pubDate' => $entry->pubDate(),

  12:             );

  13:     }

  14:     

  15:     return $entries;

  16: }

All what this function does is iterate over all of the entries of the given feed and return them as an array. I don’t really like this approach and it has some flaws, because not all feeds are having the same fields and sometimes it would be better just to copy the original node element to the new feed. As far as I know, it can’t be done (easily at least) with Zend_Feed (anyway I didn’t find a way, so if you know different – please drop me a line). Anyhow, the code sample above creates a feed entry with the most basic (and mandatory) fields.

Also notice that I convert the publish date of each RSS item to a timestamp using the strtotime function. This function can take a time or date values in various formatting and converts them back to timestamp – very useful.

Now if we just use it as is, meaning:

   1: $merged_feed['entries'] = array_merge (

   2:     getEntriesAsArray ($feed1), 

   3:     getEntriesAsArray ($feed2));

We will have all the entries from both blogs in the new feed, but they won’t be sorted. The basic array sort functions of PHP can easily sort numbers or strings, but if we want to sort something more complex we need to use the usort function. If you’re unfamiliar with the usort - it’s an array sorting function that takes a custom function for comparison of the items (see the manual page for more info). So let’s write our comparison function:

   1: function cmpEntries ($a , $b) {

   2:     $a_time = $a['lastUpdate'];

   3:     $b_time = $b['lastUpdate'];

   4:             

   5:     if ($a_time == $b_time) {

   6:         return 0;

   7:     }

   8:     return ($a_time > $b_time) ? -1 : 1;

   9: }

This function will sort the entries’ timestamp in a descending order – like the entries should be. Now that we have the comparison function, sorting the RSS entries is quite easy:

   1: usort ($merged_feed['entries'], 'cmpEntries');

And now we’re practically finished. The image below shows how the merged feed looks before the sort (left) and after the sort (right):

(I’m sorry that the time stamps are in Hebrew – that’s because of my computer’s locale settings. Just notice the time and dates).

There are some things we can improve in this example, like defining the number of entries we take from each post, adding to each post title the original blog name and maybe caching the entries from the feeds so we don’t have to read it each time the RSS readers pings the page (using Zend_Cahce). If anyone interested, I will cover this issues in next posts (just leave a comment).

It came out longer than I imagined, I guess that’s because of all the source code examples. Any comments, ideas and better practices are mostly welcomed!

Arik

I searched the web for a generic printer friendly CSS for WordPress or something similar, but found nothing. I did find some helpful resources like:

1. Codex: Styling for Print – explanations, samples and links
2. Aleeya.Net: CSS Printer Friendly for WordPress – a sample CSS (didn’t work on Cutline theme) an some tips on how to make your own CSS.
3. A List Apart: Going to Print – article by A List Apart on how to make a CSS for printer-friendly page version.

After reading this , I understood that there’re no shortcuts – I will have to make a CSS suitable for my theme by myself. I decided to make a printer-friendly CSS for the Cutline Theme (see it working on Opher Brayer’s Blog). Although I’m not a CSS expert it wasn’t that hard, and didn’t took more than 1 hour.

The process of making the new CSS are as following:

1. Make a copy of the original CSS file (usually style.css) and name it print.css.
2. Now go through the CSS and replace every styling that seems that doesn’t need to be on the paper with display: none. (see sample).
   
3. Now edit your Header.php file and add to it the line :
   <link rel="stylesheet" type="text/css" media="print" />
4. From this point you can start testing your results. Just open any of your posts in a web browser, and watch the print-preview (usually available in the File menu). You will probably see still some stuff that shouldn’t be there, bad font sized, etc… What I did is using A List Apart recommendations and tips – setting the background color to white, making all my font size 12pt, adjusting links colors, removing the heading font sizes (so that they will be adjusted to the main font size) and so on.
5. I did some adjustments to the footer.php file too:
   1. I put the “Cutline by Pears…” notice in a div, so that I can make it vanish in the printer version.
   2. I added the permalink there, so that it will be printed with the text. I had to modify the original style.css to make it invisible on the screen-version.
   3. Added the printer friendly web site Pixel Badge (see below).
6. Also I made the text float around the images, so it will save space…
7. There’s a trick to make the link address appear with the link title, but I didn’t like it so I didn’t add it to my CSS. You can see a sample of how doing this on the A List Apart article.

That’s it! You can download the CSS I made along with all the modified files in one small ZIP file – Cutline_PrinterFriendly.zip.

Because currently the user can’t know if the site uses a different CSS file without reviewing the sourcecode of a page, I’ve
created a Pixel-Badge (using CoolText) that states that the page is Printer-Friendly.

(available on Flickr – just click on the badge)

I’ve created a section on the mentioned above Codex page named “Themes with Printer Friendly CSS” . I welcome you to post there links to printer friendly themes and printer friendly CSS files for themes made by others.

On next week I’m planning making fUnique theme printer friendly (that’s the theme that being used on this blog).

I hope this will help you, and of course – your comments are very welcomed.
Arik