RSS

RSS - Machine-readable news and blog feeds. XML format.
e.g. Client app drags multiple feeds into a viewer of feeds you are interested in.
e.g. Client embeds a widget on their site that displays an interesting feed in a sidebar.

Sample widget - "Feed2JS"

Below is a sample RSS widget on my site.
The Feed2JS site provides support for RSS widgets on your site.
See the original XML feed at Irish Times. I will talk to feed2js.org to get this. I will not talk to the Irish Times site directly.

My site includes code like this (View Source to see):


<script src="https://feed2js.org/feed2js.php?src=FEEDURL" >

FEEDURL is the Percent encoded URL of the feed.
Script runs when page loaded.
What script runs? The output of remote PHP. i.e. The output of the PHP program is a Javascript program!
See the output Javascript program. It's just a bunch of "document.write" statements. i.e. It's really data, not a program. But we cannot easily "include" remote data in a page. But we can easily include remote Javascript statements. So that's why we do it that way.
Summary: My page load makes PHP run on feed2js.org. This fetches current XML feed from Irish Times, parses it, translates it into some nice HTML and produces a series of Javascript "document.write" statements to output that HTML. It then returns that Javascript code as its output. So my page is now including that Javascript code, so it simply writes the HTML at the point where it is included.

Problem: Column width of unknown feeds.
- If (as would be typical) you include the feed in a column on a blog-like page, you want the feed output to stay within the designated width of that column. But if the feed contains a word that cannot be broken (e.g. a URL), this will push out the column width.
- Solution with Feed2JS: No descriptions (desc=0) for feeds whose descriptions may contain a URL.
- Better solution: Word wrap the data using CSS word-wrap. See example in a box here.
Problem: Badly-formed feeds.
- Remote RSS feeds are sometimes badly-formed, leaving error message in the widget on your site. (In my experience, this happens a lot.)
- Solution: Feed Sanitizer. Link to "sanitized" version of the feed instead. [This is now gone. Any alternative?]
Problem: Feed site is down.
Problem: Feed2JS site is down.

You can host the feed2js script yourself so you are not dependent on the feed2js site.
Or you can host or write your own PHP script to process RSS.

RSS feeds are one among many ways of receiving feeds. They are in decline compared to other ways:

JSONP feed - Javascript can get data direct from any website. No need for a feed2js.org site.
Web APIs
Social media feeds and timelines. Twitter and Facebook. Subscribe to the sites you want. Then your feed/timeline has all the updates you want combined.