Connecting Xcelsius to an RSS Feed

by Ryan Goodman

For those of you who are not familiar with RSS, Really Simple Syndication or Rich Site Summary are web services for public consumption over the world wide web with no particular limitations on security or usage. Today, RSS feeds are syndicated from news organizations, general interest groups, blogs, and forums. The data is streamed as XML that can be easily consumed or remixed with any RSS reader or Aggregator. It is the lightweight nature and flexibility of this standard across multiple platforms that have allowed this technology to flourish. In fact, this Blog has a syndicated RSS Feed. I will save my views on re-mixing information and RSS related technologies for another article…

Since you need an RSS reader to consume XML data, why not use an Xcelsius dashboard to present context specific information. Let’s see how we can achieve this using Excel 2003 and Xcelsius to consume and present Google News RSS.


Download Source Files

For this article, I am not going to go into depth about XML Maps in Excel 2003, so for detailed info, you can download a great whitepaper on the Xcelsius learning center site: Connectivity Using XML Maps in Excel 2003

Consume the RSS feed as an Excel XML Map

1. In the toolbar go to Data>XML>XML Source…
2. At the bottom of the right hand side toolbar click on the XML Maps button.
3. Click on Add to add a new XML map
4. Instead of navigating to a file on your PC, you will paste your RSS feed URL. In our case we are using a Google news RSS feed. Lets make our default feed specific to Xcelsius: http://news.google.com/news?hl=en&ned=us&q=xcelsius&ie=UTF-8&output=rss. If you were to enter this URL into your browser, you would see the XML in your browser. It is this XML that we are going to stream to our Xcelsius model.
5. With your XML Map added, click OK and you will notice the hierarchy displayed on your right hand side toolbar.
6. In this case we are going to utilize 2 elements from this list: Under the Item folder, you will drag and drop Title and Link and place them next to each other in any cells. Lets use B5 and C5 as our cells.
7. Now you have mapped the elements to Excel. Lets see what the data will look like when it is returned. Right click on cell B5, hover over XML, and click Refresh XML Data. This will force Excel to query Google news and return the data based on the RSS feed URL we specified earlier.
8. Before we save and move to Xcelsius we want to ensure that this Feed reader will scale appropriately. To do this, you will need to expand the mapped range. You will notice a blue border around your mapped cells. Go to the lower right hand side and click on the handler to exapand the number of rows to B20 and C20. This will ensure that your reader will scale when there are more news articles.
9. Save your Excel file

Configure Xcelsius to Show the RSS Data

1. In Xcelsius you will first import your Excel file. Upon importing this file Xcelsius will automatically understand that the Excel file contains XML maps.
2. In the toolbar, click on Data>XML Map Options. You will see the same URL that you defined in Excel. We can change the URL or even bind it to a cell in our model. Click OK.
   * In the final advanced model that I provide on this blog, I leverage this functionality to dynamically generate the URL based on search criteria defined in Xcelsius.
3. Import a List Box selector component and a URL button component (located in Web Connectivity folder).
4. For the List Box: Bind the Labels to B6:B20; Use the Insert Rows Option; Bind the Source Data to B6:C20; Bind the Insert In to B4:C4.
5. For the URL Button: Bind the title to B4 and the URL to C4.
6. Vuala- You now have an RSS reader
   Important Note: Do not try to preview it inside of Xcelsius: It will not work. Go to File>Export Preview

Here is a more advanced example where I take the original URL, break it apart and add a text box in Xcelsius to drive the search parameter. Then I dynamically concatenate (http://www,ryangoodman.net/blog/) the URL back together and bind that cell to the XML Map Options window (see #2). Then I add an XML map refresh button which allows me to dictate when the query is triggered. I have provided all source files so you can reverse engineer and play around.

Download Source Files

Addressing Cross Domain Access to the RSS feed
If you download and run these files on your desktop, it will work perfectly. Because of Flash security settings specific to cross domain access, you have to normally setup a cross domain policy file. This cross domain policy is applicable to scenarios where you have access to the data source.

In our case we obviously do not have access to the Google News servers. For this scenario, we will need to look at creating a PHP proxy to allow for cross domain access. To use this proxy, you will specify your RSS url as a parameter inside of the query string:
“http://your_site/xml_proxy.php?=url=your_rss_feed”

So in the our Xcelsius model we would define the concatenate formula to generate the following URL and ensure that this URL is linked within the XML Map Options window (see #2). http://ryangoodman.net/blog/../xml_proxy.php?url=http://news.google.com/news?hl=en&ned=us&q=xcelsius&ie=UTF-8&output=rss.