Wordpress development techniques #2 – Fetching RSS feeds with wordpress
As promised last week, this week we are looking at fetching RSS feeds with Magpie RSS.
Magpie is an PHP based RSS feed parser; I.E. It fetches RSS feeds to display in other places, which gives it many uses.
Unknown to many, wordpress has the magpie RSS parser built in, this article will teach you how to use it, and also how to fetch and show someones del.icio.us bookmarks!
Fetching feeds in wordpress
Wordpress contains two functions for fetching feeds:
fetch_rss-This function fetches and parses an RSS feed.wp_rss– This function fetches and parses an RSS feed, then displays the results in an unordered list.
These functions use magpie for parsing the RSS, and Snoopy for retrieving the RSS.
Uses the MagpieRSS and RSSCache (http://magpierss.sourceforge.net/) functions for parsing and automatic caching and the Snoopy HTTP client (http://sourceforge.net/projects/snoopy/) for the actual retrieval.
Including Magpie in a template or plug in
Magpie RSS is built into wordpress’ rss-functions.php file (or rss.php in newer versions). It contains the functions needed to fetch feeds, so it needs to first be included:
1 2 | // Include the RSS functions. Older versions of wordpress could use include_once (ABSPATH . WPINC . '/rss-functions.php') or include_once (ABSPATH . WPINC . '/rss.php');; include_once(ABSPATH . WPINC . '/rss-functions.php'); |
Fetching the feed with fetch_rss
Next lets tell wordpress what feed we want to parse, and put it to work! If you want to get the results and output them yourself, use fetch_rss.
1 2 | // Fetch a feed $feed = fetch_rss("http://yourfeedaddress"); |
To limit you results you can slice the array of results:
1 | $items = array_slice($feed->items, 0, $maxitems); |
After that, use a loop to go through the array contents and output the results (see the del.icio.us bookmarks example further down for more detail on this).
Fetching the feed with wp_rss
If you want to output the results in an unordered list right away, use wp_rss.
1 2 | // Fetch a feed, replace $limit with the max results you want wp_rss("http://yourfeedaddress", $limit); |
Example output
The below example shows output from my bookmarks feed using wp_rss.
wp_rss(‘http://del.icio.us/rss/mikejolley’, 5);
Fetching del.icio.us bookmarks – example
The following code gets my last 5 del.icio.us bookmarks, and outputs them to the page.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 | <?php // Include the RSS functions of wordpress include_once(ABSPATH . WPINC . '/rss-functions.php') // Grab my RSS feed $feed = fetch_rss("http://del.icio.us/rss/mikejolley"); // I want 5 results please $maxitems = 5; $items = array_slice($feed->items, 0, $maxitems); // Output the results! if(!empty($items)) { echo '<ul>'; foreach ($items as $item) { echo '<li>'; echo '<a href="'; // This is a bit messy, but it makes the output valid XHTML strict by removing ampersands $item['link'] = str_replace("&", "&", $item['link']); $item['link'] = str_replace("&&", "&", $item['link']); // End of messyness. Output the link echo $item['link']; echo '">'; // Output the title echo $item['title']; echo '</a>'; // If i've written a description, output it if (isset($item['description'])) { echo '<br />'; echo $item['description']; } echo '</li>'; } echo '</ul>'; } ?> |
Neat huh? See what it outputs below:
$maxitems = 5;
$items = array_slice($feed->items, 0, $maxitems);
if(!empty($items)) {
echo ‘
That line of code simply sets the output of the fetched feed to be in UTF-8 encoding. Handy.
More about wordpress rss functions
- http://codex.wordpress.org/Function_Reference/wp_rss
- http://codex.wordpress.org/Function_Reference/fetch_rss
- http://magpierss.sourceforge.net/
Found this post useful? Why not buy me a coffee!
Vincent says:
Do I still need to install the feedList 2.2 plugin? Or does Magpie handle my cache in the database?
The last time I used feeds it caused a long load e.g. see the feeds behind the links on this page: http://www.bangkoktalk.nl/?page_id=29 (old wp version)
Would be nice just to handy my feeds like you described
Where to place:
1 define(“MAGPIE_OUTPUT_ENCODING”, “UTF-8″);
Great post!
Comment made on July 2, 2007 at 12:45 am
Mike Jolley says:
Well, both sections say, and I quote:
So Its automatic.
Stick the define line just before the fetch_rss line.
Comment made on July 2, 2007 at 6:19 am
Jenny says:
I am totally lost. But I wanna figure this out. I really do.
Comment made on July 16, 2007 at 5:18 pm
Mark says:
Hey, man. I love your site. I use it all the time to make sure I’m coding stuff right. :]
Comment made on August 3, 2007 at 2:02 am
Lakshmi Mareddy says:
Pretty cool Mike! or should I say “Jolley Good”… I had played with Magpie separately long back, but didnt know it was built-in in WP. Now after reading your article, my mind is racing… A big THANK YOU to you for coming up with this…
Comment made on September 22, 2007 at 10:52 pm
Christopher Miles says:
Thanks a lot for this post; I’m now using the native RSS fetcher in Wordpress to create a blogroll on my site using del.icio.us links, and a current and recent reading list from my Google Library RSS feed
I’m spending half my waking day thinking of new and fiendish ways of parsing RSS feeds to my site now!
(“Half my waking day” and “fiendish” are probably overstating it a bit.)
Comment made on November 20, 2007 at 2:38 pm
Mark says:
Your lesson is similar to one I found on the wordpress codex but yours is more detailed. I have one question: Do you know if there is a way to display/echo the pubdate for each item? I have not been able to figure that out.
Thanks!
Comment made on December 14, 2007 at 11:07 pm
Steve says:
Is it just me, or does anyone else see, “Warning: array_slice() [function.array-slice]: The first argument should be an array in /home/sites/blue-anvil.com/public_html/wp-content/plugins/phpexec.php(41) : eval()’d code on line 4″, in the example boxes? The only reason I ask, is because I am getting this error too, when I try to parse a feed from my own website. It works the first time, but then on refresh it dies and give me a similar error.
Comment made on May 7, 2008 at 4:59 pm
Jamie says:
How can I add things like author and date? I’ve tried things like:
echo $item['dc:publisher'];
echo $item['pubdate'];
Unsuccessfully.
Comment made on May 12, 2008 at 9:46 pm
Mike Jolley says:
Not sure why there are errors…maybe wordpress team changed something. There is a new function called get_rss however. Maybe that will work.
Comment made on May 13, 2008 at 11:24 am
bamajr says:
There was an article which caught my attention on MSN about Facebook. (See it by clicking here)
This article was written by a writer for PCWorld and posted on the PCWorld site. (See it by clicking here)
This article was pulled by MSN and displayed as a post to their tech site.
Credit was given to the PCWorld Writer, but it was posted as a new article on MSN.
This is what I’m trying to do. I want to pull related tech articles from places like PCWorld and put them on my site as a new blog article (Of course, credit would be given to the original writer!)
How is this done?
Comment made on May 21, 2009 at 3:40 pm