RSS2.0 description reprint -

RSS is everywhere!
Today, you can find thousands of RSS feeds. Weblog users, news publishers, government agencies, and many personal and commercial Web sites support this format. Java technology, PERL, PHP, Python, and other major programming languages provide developers with tools to process RSS. Many readers and aggregators work in Web, desktop, and even e-mail client programs. RSS has become the de facto standard for chained content and metadata on the Internet.
This article will observe the current RSS 2.0 specification. I am not going to discuss the rich and colorful features of the format and the arguments surrounding it, otherwise I will not be able to discuss other content.
On the contrary, this article will provide you with a small amount of background knowledge, examine the usage of this format, and list some of the more popular tools for processing this format. The article will discuss the specific details of this format, give you some examples, and explain what you need to know before you start. Finally, this article will involve some new features of RSS 2.0. At the end of the article, you will find a wealth of mineral deposits-a long, annotated list of RSS references.

What is RSS?
What exactly does “RSS” stand for?
Like many standards, it is difficult to get people to agree on even the most basic aspects. Some people say it means “RDF Site Summary”, others say it means “Really Simple Syndication”, and others believe it stands for “Rich Site Summary.”
According to Dave Winer (who is the author of the current specification), “There is no consensus on what RSS stands for. It is not an acronym, but a name. The latest version of the specification may call it an acronym , I hope it won’t affect too many applications.”
In any case, RSS stands for one thing-a format for chaining content on the Internet.

RSS is a format for chained content and metadata on the Internet. Usually used to share headlines and links to news articles. For news articles, the actual article is not necessarily shared, but metadata about the article is usually shared; this metadata can include the title, URL, or abstract. For publishers, RSS is an important tool because feeds can be used to chain content and integrate third-party content into your site.
RSS is an XML dialect. All RSS files must conform to the XML 1.0 specification published on the World Wide Web Consortium (W3C) website.
The following is a typical example of how to use RSS:
•A publisher has some content that he wants to publish.
•They created an RSS channel for this content.
•This channel contains some items about the web page that you want to promote.
•This channel can be read by remote applications and converted into titles and links. These links can be added to a new Web page or read by dedicated readers.
•People see this link from different sites and click on the link to enter the original publisher’s website.
Although headline chaining is the most common use of RSS, it can also be used for other purposes. RSS is a very popular format in the weblog community. It is also used for photo books, classified ad lists, recipes, comments, and tracking the status of software packages.
RSS feeds are used as a way to convey information in e-commerce. For example, Amazon provides news feeds to customers based on its Web services platform. This allows you to learn about the best-selling books in your news reader, or include information about related books sold by Amazon on your Web site.
In the past few years, RSS has grown tremendously in popularity. Syndic8.com maintains an index of RSS channels, and its feed list has grown by approximately 1400% in two years. Yahoo News, BBC, Slashdot, LockerGnome, Amazon, CNN, Wired, Rolling Stone, and Apple Computer are among the most popular sources of RSS feeds.
News Readers
As the number of news feeds increased, a new type of software appeared: news readers. The news reader is a personal aggregator – to help you discover and organize a list of channels of interest. Once the channels are selected, you can view these channels using the consistent interface of the reader. The news reader checks for updates on the channels you are interested in and converts them into HTML that can be viewed. The more common news readers include BlogStreet, FeedReader, AmphetaDesk and NewsGator.
Discover RSS feeds
You can use search engines to find content in RSS format. For example, when using Google, you can add “filetype:rss” to the search to search for the search term in the .rss file.
Special search engine makes content search easier. Feedster monitors the weblog and allows you to search through an index of log entries, view by relevance, date, and rank (logrank). When you are searching, Feedster creates an RSS feed according to your requirements. This feed can be added to your news reader so that you can see all the latest activities related to the search request, and you don’t even need to leave the news reader.
DayPop searches for news, blogs and RSS feeds. It allows you to track popular news in the weblog world. It provides the 40 most popular weblog links. This is a link to the most popular article in the world. It creates a list of the most popular words used in the weblog. It also ranks weblogs based on citations and provides a list of weblogs most popular with other webloggers. You can also customize the search. Both the rating list and custom search have RSS feeds that can be imported into your news reader.
New features of RSS 2.0
RSS 2.0 is based on the RSS 0.91 specification. It is backward compatible, so any tool that handles RSS 2.0 should also be able to handle 0.91 feeds. The upgraded specification adds a few elements, such as and .
It also removes some restrictions. In the past, the and elements could only be http or ftp, now any valid URI can be used. In RSS 0.91, each channel can only contain 15 items, and there are restrictions on the length of the elements, and these restrictions are now removed. However, larger values should still be used with caution, as they may cause problems for older applications.
But the bigger change is the ability to use namespaces to extend this format. RSS 2.0 supports namespaces, a standard way of adding elements that are not in the specification. As long as it is defined in a namespace, the feed can contain new elements.
RSS 2.0 Overview
RSS is an XML dialect used to chain Web content and metadata. RSS 0.91 is the most commonly used of several available versions. For the new RSS feed, a better approach is to use version 2.0, because this is the current specification and, as mentioned earlier, it is backward compatible with 0.91.
Dave Winer wrote version 2.0 of the specification. Modifications to the specification may become difficult to use or damage existing applications, which he consciously avoided. Winer summarized his thoughts: “Keep it simple. This is the value of RSS. Anyone who knows a little HTML can understand RSS. This is extremely important!”
The specification is released under the Creative Commons license (see Reference material). This means that you can copy and distribute the specification for free, and do derivative work, and you can freely use it for commercial work. An advisory committee is responsible for updating specifications, promoting specifications, and writing documents.
RSS file format
The RSS file consists of a element and its sub-elements. In addition to the channel content itself, also contains elements representing channel metadata in the form of items-such as , <link>, and <description>. Items are usually the main part of the channel and contain content that changes frequently. Channel Channels generally have three elements that provide information about the channel itself: •<title>: The name of the channel or feed. •<link>: URL of the website or site area associated with the channel. •<description>: Briefly introduce what the channel does. Many channel sub-elements are optional. The commonly used <image> element contains three required sub-elements: •<url>: Represents the URL of the GIF, JPEG, or PNG image of the channel. •<title>: The description of the image. When the channel is rendered in HTML, it is used as the ALT attribute of the HTML <image> tag. •<link>: The URL of the site. If the channel is rendered in HTML, the image serves as a link to this site. <image> also has three optional sub-elements: •<width>: Number, indicating the pixel width of the image, the maximum value is 188, and the default value is 88. •<height>: Number, indicating the pixel height of the image. The maximum value is 400, and the default value is 31. •<description>: Contains text, which can be used as the title attribute of the link element formed around the image when rendered. In addition, many other optional channel elements can be used. Most of them are self-explanatory: •<language>:en-us •<copyright>:Copyright 2003, James Lewin •<managingEditor>:dan@spam_me.com (Dan Deletekey) •<webMaster>: dan@spam_me.com (Dan Deletekey) •<pubDate>: Sat, 15 Nov 2003 0:00:01 GMT •<lastBuildDate>: Sat, 15 Nov 2003 0:00: 01 GMT •<category>: ebusiness •<generator>: Your CMS 2.0 •<docs>: http://blogs.law.harvard.edu/tech/rss •< cloud>: Allows the process to register as “cloud” and notify it when the channel is updated, which implements a lightweight publish-subscribe protocol for RSS feeds. •<ttl>: Time to Live is a number indicating the number of minutes the feed is buffered before being refreshed. •<rating>: PICS rating about the channel. •<textInput>: Define the input box that can be displayed with the channel. •<skipHours>: Tell the aggregator which hours of updates can be ignored. •<skipDays>: Tell the aggregator that the update of that day can be ignored. Item Item is usually the most important part of the feed. Each item can be a record of a certain weblog, complete documentation, movie reviews, classified ads, or any content that you want to link with the channel. Other elements in the channel may not change, but items often change. You can have as many items as you like. The previous specification limit was 15 items, which is still a good upper limit if you want to maintain backward compatibility. Elements of news items Each item usually contains three elements: •<title>: This is the name of the item, which is converted into a title in HTML in standard applications. •<link>: This is the URL of the item. The title is usually used as a link, pointing to the URL contained in the <link> element. •<description>: Usually used as a summary or supplement to the URL pointed to in the link. All elements are optional, but an item at least contains either a <title> or a <description>. The item has some other optional elements: •<author>: the e-mail address of the author. •<category>: Support organized records. •<comments>: The URL of the comment page about the item. •<enclosure>: Supports media objects related to this item. •<guid>: The only permanent link associated with the item. •<pubDate>: When was the item released. •<source>: Which RSS channel the item comes from, very useful when grouping items together. Listing 1 is an example of an RSS 2.0 file. Note that the channel is included in <rss version="2.0">. This is a very basic example of how items and images are included in the channel. The elements shown are the most commonly used channel sub-elements. List 1. Example RSS 2.0 file <?xml version="1.0"?> <rss version="2.0"> <channel> <title>The channel’s name goes herehttp://www.urlofthechannel.com/
This channel is an example channel for an article.

en-us

The image title goes here
http://www.urlofthechannel.com/images/logo.gif http://www.urlofthechannel.com/

The Future of content

link>http://www.itworld.com/nl/ecom_in_act/11122003/
The issue of people distributing and reusing
Digital media is a problem for many businesses. It may also be
a hidden opportunity. Just as open source licensing has opened
up new possibilities in th e world of technology, it promises to do
the same in the area of creative content.

Online Music Services-Better than free? http://www.itworld.com/nl/ecom_in_act/08202003/
More people than ever are downloading music from
the Internet. Many use person-to-person file sharing programs like
Kazaa to share and download music in MP3 format, paying nothing.
This has made it difficult for companies to setup online music
businesses. How can companies compete against free?

related tools
Due to the popularity of RSS, many tools have emerged that enable you to use these files in basically any environment:
•Java technology: an RSS Utilities Package that can be found on the Sun site, supports the use of tags in JavaServer Pages Library. It also includes an RSS parser.
•Perl: There are already several Perl tools that handle RSS. XML::RSS provides a framework for creating and maintaining RSS files. It supports conversion between commonly used versions.
•Python: RSS.py is a set of classes for using RSS channels through Python.
In addition, many content management and weblog tools also directly support RSS. Most weblog tools, including Movable Type, Blogger and Radio Userland support RSS. Some content management systems, including Zope and CityDesk now also support it.
Extended RSS
RSS 2.0 has many optional elements, including those required by most channels. But it also supports extensibility, so you can use elements that are not in the specification. However, the RSS 2.0 specification did not spend much time defining how to implement extensions. Regarding extensibility, the specification summarizes: “RSS feeds can contain elements not described on this page, as long as these elements are defined in a namespace.”
This leaves a lot of room for imagination! Fortunately, the specification contains an example, you can refer to several examples currently in use.
The basic idea is that you can add as many tags as you need-but adding elements with multiple meanings is too easy. People who use your channel may not know what a tag means. For example, if I want to use the tag in a channel, its meaning is not very clear. Web experts may think that this label refers to Analog, which is the most popular Web log file analyzer. Science fiction fans might think that this label is about Analog, a classic science fiction magazine. Musicians may think it refers to the popular type of synthesizer, biologists think it is an organ, and electronic engineers think it is a circuit. Vagueness makes it difficult for people to understand the meaning of the label.
So, RSS allows you to add any tags you like, but it must be used with the namespace. This helps clarify the meaning of the label.
Going back to the example, I might want to create a set of tags about e-commerce and make the tag an “e-business” element. To this end, I added the following namespace:
xmlns:ebusiness=”http://www.lewingroup.com/ebusinessChannel”
This is created A namespace named “ebusiness” and indicates that the documents in this namespace are on my site. In order to use the tag, I can use this format: . This can be distinguished from other similar meanings, such as or .
Regarding extensibility, a more practical example can be found in the sample file of the RSS 2.0 specification:
Listing 2. Namespace in the sample file of the RSS 2.0 specification

http://backend.userland.com/blogChannelModule”>

Scripting Newshttp://www.scripting.com/
A weblog about scripting and stuff like that.
en-us

http://radio.weblogs.com/0001015/userland/scriptingNewsLeftLinks.opml

Joshua Allen:
http://www.netcrucible.com/blog/2002/09/29.html#a243″>
Who loves namespaces?

pubDate>Sun, 29 Sep 2002 19:59:01 GMT
http://scriptingnews.userland.com/backissues/2002/09/29#When:12:59:01PM item> In this example, a namespace called blogChannel is defined. It points to a document that explains the usage of several new elements commonly found in weblog. One of them is . The documentation states that blogroll is a collection of links in weblog that point to sites related to the content of your weblog. The tag provides the information needed by the user or software, knowing that blogRoll is an element defined in the blogChannel namespace, and the location of this document can be found. Similarly, RSS 2.0 only requires namespaces for elements that are not part of the specification. All basic tags are assumed to be in the RSS 2.0 namespace. This makes this format easier to use, because unless you need to extend RSS, you don’t need to know the namespace at all. Conclusion This article examines the importance of RSS in the field of content chaining and aggregation. The article mainly discusses RSS 2.0, because this is the latest specification version, and it is rapidly becoming popular. This article also examines the tools available for processing RSS, including aggregators, validators, and parsers. For more information, please refer to references.

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