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. If you have made any changes in the HTTP method, click Load
to see the changes. Do not click Load
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.Source
HTTP MethodURL Parameters
- Select URL 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. Enter the URL and click Load to retrieve the parameters from the URL. If you want to change the HTTP method, click Edit. You can click Show URL Parameters to see the information that was retrieved.
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.
If an administrator has enabled the republish role, the URL field will be available only for users who have the republish role.
- Select From Catalog if the source of the data is a feed 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.
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.
If an administrator has enabled the republish role and you have not been granted the republish role, the search will display only public feeds and feeds that you own.
Click Show URL Parameters to view 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 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 that you set as the output when you preview or run the feed. RSS feeds contain their data in the XML <item> 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 is not displayed. 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 the Transform operator, 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, you can select an element that is nested under the <item> element.
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. If the source is a feed in the catalog, the feed might already have a refresh interval defined. The actual interval used is whichever has the greatest value: the value that you specify here or the value that is already specified for the feed.
You can improve performance by specifying an accurate interval value. For example, if you know that the feed is only updated once a day, set the refresh interval to 1 day
If the source comes from a URL, the default value for refresh interval and its effect on the data mashup depend on the HTTP Method.
GET HTTP method: The default refresh interval is one hour.
POST, PUT, or DELETE HTTP methods: The refresh interval depends on if you are building the data mashup in the data mashup builder and using the Preview option in the operators or if you are running the data mashup. Running the data mashup means viewing it with View Feed in Browser
option or clicking the Run icon in the data mashup builder.
- Building the data mashup: Because multiple calls are made to the Source operator when you use the Preview option, by default the feed from the Source operator is cached for one day. You can refresh the source and clear the cache by clicking the Run icon.
- Running the data mashup: The refresh interval option is length of time that the feed from the URL is cached during run mode only. By default, the refresh interval is the Always from Source setting, which means that the feed is not cached. If you want to cache the feed from the source when you run the data mashup, change the refresh interval appropriately.
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
Specifying HTTP methods in the Source operator: imc3
If you choose the URL option in the Source operator, you can change the HTTP method from the default GET method to POST, PUT, or DELETE. You can also edit the HTTP header information, the Content-Type, and the content information.
Parent topic: Operators: imc3
Tips for better performance in the data mashup builder: imc3
Casting data type values: imc3
Using JSON format in the Source and Publish operators: imc3
Server nonfatal errors in the Preview tab in the Details window: imc3