Padraic Brady has written up a post on how he implemented conditional fetching (GET) as a part of the Zend_Feed component of the Zend Framework.

You see, by default, Zend_Feed is stupid. It will blindly drag in whatever RSS you point it at, parse it, present an accessible API (which is largely an abstract API across PHP DOM), and then merrily sit back while you are driven demented. There is a problem in blindly fetching RSS and parsing it - RSS feeds from a huge number of online sources only change rarely. The rest of the time the feed is unchanged.

The key is in the "Last-Modified" header data of the remote file (and ETag). He shows how to use this knowledge in a simple example - pulling data with a ZFBlog_Aggregate class and dumping the contents into a database table. This code checks the return status for a 304 ("Not modified") and closes out the connection if so. Otherwise it grabs the content and updates the database with the most recent fetch times to compare to the "Last-Modified".

In a new post to his blog today, Danne Lundqvist shares his method for creating a blog aggregator (in the style of the planet-planet sites) to re-aggregate all of the feeds back ou tinto one.

Lately I have begun to get more and more annoyed with my feed reader. I use a simple feed reader which lack most features except for subscribing to and reading feeds. The one thing that annoys me the most is that it can't aggregate several feeds into one feed. Yesterday I finally decided to scratch that itch.

His method uses the Zend Framework to accomplish the goal - and "the whole website logic (both model and controller) is about 200 lines of code". There's no exception or error handling in it, but it works and the Zend_Feed module works well to grab just about any kind of feed.

In the continuing series on RSS files, DevShed has posted this new part with a focus on the "theoretical aspects" of developing an RSS file.

These aspects include things like examples of the elements it can contain, elements that are required for it to be a compliant RSS document, a look at the enhanced RSS functionality and structure (more information about the creator of the RSS embedded in the data), and even a look at what an aggregator is and what they would do with your RSS file.

Keep an eye out for the last installment in the series - a look at actually creating the RSS file from your data (probably from a database) and displaying it for the world to see.

Hasin Hayder has a new note on his blog today about a new site he's developed to aggregate the feeds from other PHP-related sites and blogs as well as a few on other topics as well.

FeedPHP is a free RSS aggregator which collects feed, parse and display the titles with a link back to the original source. The whole site is a single page with mod_rewrite tricks.

For performance, the contents are cached for several minutes, otherwise my site will be convicted for consuming excess bandwidth from those sites. Moreover, the site will be extremely slow for consuming remote contents frequently. Output buffering is used to serve contents quickly.

There is definitely tons of content here, but my only complaint is that it seems to load each section a bit slow, especially for cached data? Other than that, it's a great resource for an overview of what's happening in the PHP (and related) communities.

In a previous post crynobone shared a method for creating RSS feeds from the information stored in a database. He's back this time to handle just the opposite - gathering the data from multiple RSS feeds into a simple aggregator.

What is RSS Aggregators? Why you may already familiar with Feedburner, Live.com, My Yahoo and Google Personalized Page as well as other News Aggregators where you have freedom to control your own News. Here your chance All we do need is to get Magpie RSS parser for PHP and some AJAX coding to create our very own News page.

As mentioned, the entire setup revolves around the MagpieRSS library, making it a simple task to pull in and work with the contents of remote RSS files. He even shows how to use a simple Ajax connection to request the latest updates you've fetched and stored in the database.

On our sister site, AjaxDeveloper.org, today there's a new post with information about creating your own RSS aggregator with the help of PHP and Ajax.

Imagine using a simple HTML file to send a request to a server-side script, receive a custom XML file based on that request, and then display it to the user without ever refreshing the browser! Kris Hadlock explains how to use a combination of PHP and AJAX to create real-time data transfers in any application without a browser refresh.

They (obviously) require some knowledge from the developer of PHP and Javascript, but other than that, they pretty much give you all the code you'll need...