Jun 30 2008
Common problems faced in Yahoo Pipes
Why my Yahoo Pipe shows “No Results” on running it?
Beginners in Yahoo Pipes may end up getting this error message while running their Yahoo Pipes. There are two reasons for a Yahoo Pipe not showing any results.
- The Pipe Output is not wired.
Make sure that the Pipe Output is wired. Verify the raw output in the debugger.
No description element
Make sure your pipe has an element called “description”, which is required for any HTML based feed output. Output the HTML code of your pipe only to the “description” element. Having your HTML output in any other element will make your pipe output go unrecognized by feed readers.
If your pipe still shows no results, ensure that your pipe sources, i.e. modules like Fetch Page, Fetch Data and Item Builder, pull data needed for the pipe. If you find nothing fishy, debug the pipe starting from “Pipe Output” module and navigating upwards.
Finding it difficult to Regex multi line text?
Simple. Convert it into single line and Regex it. Use a Regex command to replace the new line characters with empty text and apply your Regex commands on the single line text. Do like this,
Noted the option boxes checked in both the commands? Its ‘g’ and ‘m’ for the new line replacement and ‘g’ for remaining commands.
How to add more elements to the feed?
Use the Rename module and copy an existing element. You can remove the source element’s contents by using a Regex module as below.
Connecting feed output to a string module
Yahoo Pipes doesn’t allow you to wire a port of type “items” to a port of type “string”. But in many cases we require this wiring to process the strings in the feed items. Here is how you should do this…
Add a loop module and place the string module within the loop module. Then connect a module’s “items” output with the loop module. Now the fields in the string module, which is now hosted on the loop module, will be populated with the elements available in the input feed. In the loop module’s field ‘For each’, select the element which has to be processed by the string module. This element in each item of the input feed will be processed by the string module and the string output can either add on to or replace the elements in the input feed, depending on your selection between “assign results” or “emit results”. Here is a sample Pipe that demonstrates Loop module.
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