There are two places parameters could be introduced in a feed mashup, from the source operator and the filter operator. Any variables added to a mashup that are unassigned becomes parameters.
The following are the typical steps to create a parameterized feed:
1. You start by selecting New Feed Mashup
on the Home tab in MashupHub.
2. Drag a Source operator on to the canvas and specify the URL for the feed that you want to parameterize.
3. Drag a Filter operator on to the canvas.
4. For the Input Element parameter, select the element value that you want to parameterized.
5. Specify the comparison operator for the filter.
6. For the Value parameter, select the Use a variable to return the value
7. In the Variables window, specify a name for the variable, a default value, and description.
The following examples and tutorials in MashupHub show how to use variables:
- Example - National Park Forecast Mashup
- Example - Expiring Policies Mashup
- Tutorial - Disease Outbreak Mashup
To create a parameterized feed that accepts the parameter though an XML file, see the National Park Forecast Mashup
example. This example uses the For Each operator to substitute the value of the zip codes in an Yahoo! weather URL with zip codes from an XML file.