Contents: MashupHub User and Administrator Guide : Mashup Center 2.0
Use the Source operator to specify the feed that you want to use to start your data mashup. Data mashups can use more than one Source operator.
To refresh data from a feed, use the refresh icon on the Preview
tab. Do not use the Load
button to refresh data because any URL parameters that have been modified and any changes to the properties on the Advanced
tab are lost.
The name to display on the Source operator image on the canvas.URL
Specify this parameter if the source of the data is a URL. This must be a URL on the Internet or an intranet that contains the data in an RSS, Atom, JSON, or XML format. Specify the URL and click Load to retrieve the parameters from the URL You can click Show URL Parameters to see the information that was retrieved. From Catalog
A sample URL, which you can use for testing purposes, appears in this field.
After the source loads, click the Preview tab and click Refresh to check for errors. The Source operator can generate nonfatal errors if the URL is not accessible or if the data retrieved is invalid.
Specify this parameter if the source of the data is a feed that already exists in the catalog. Click Browse to view a list of the feeds in the catalog. You can either search for a feed or scroll through the list to find a feed. Select the feed and click OK. Show URL Parameters
Tip: If you specify a search term, MashupHub searches the title and description of each object in the catalog for the term. You can specify more than one term, however each term must appear in the title or description for the object. The search is case-insensitive.
Displays a list of parameters and values that is derived from the values in the source URL or catalog feed. This button is hidden until you click either Load or Browse.
Tip: To specify that a parameter should use a variable, click on the drop-down arrow and select Use a variable to return the value.
The data mashup builder automatically selects the feed type, based on the feed type from the URL. The data mashup builder converts JSON source to XML. You can change the feed type from RSS or Atom to XML. When the feed type is XML, you have access to the full XML document in the tree. The tree is displayed when you access the properties for many of the operators.Repeating element
The repeating element is the element you set to appear as the output when you preview or run the feed. RSS feeds contain their data in the item XML element. By default, the repeating element for RSS feeds is set to item. The output from Run or Preview will show only the item elements and the children of the item element. The header information for the RSS feed will not appear.Refresh Interval
Tip: Sometimes the element that you want to work with is the root element of the feed. To use the aggregate functions in transform the root element must be selected as the repeating element. To specify a different repeating element, first change the feed type to XML. Specifying XML as the feed type and a different repeating element changes the data that is returned in the Preview tab.
You might want to select a different repeating element when working with a catalog feed. Additional elements are added to the feed when it is stored in the catalog. To access the data contained in the feed, an element that is nested under the item element can be selected.
The length of time that the feed from the URL is cached. After the time has lapsed, the feed from the specified URL is reloaded. The default time is 1 hour. If the source is a feed in the catalog, the feed might already have a refresh interval defined. The actual interval used is the value that is greater - the value that you specify here, or the value that is already specified for the feed.
Tip: You can improve performance by specifying an accurate interval value. For example, if you know that the feed is only updated 1 time a day, set the refresh interval to 1 day.
The Source operator is used in all of the data mashup examples. You can access the examples from the Getting Started actions on the Home:Catalog
Parent topic: Operators : Mashup Center 2.0
Operators : Mashup Center 2.0
Tips for better performance in the data mashup builder : Mashup Center 2.0
Variables : Mashup Center 2.0
Casting data type values : Mashup Center 2.0
Using JSON format in the Source and Publish operators : Mashup Center 2.0
Server nonfatal errors in the Preview tab in the Details window : Mashup Center 2.0