Module terminals are designed to emit or consume a specific data type. These types must be compatible in order for the modules to be wired together. For example, the Fetch module requires its input to be a URL, so you can't wire a Text Input module to it (since that gives a string). The editor will not allow you to wire together incompatible modules.
Not every module is compatible with the ForEach iterator. Some modules (like the Babelfish module) already act on every item in a feed. Others (such as User Input modules) have ill-defined semantics when applied inside an iterator. The editor will prevent you from putting an incompatible module inside of a ForEach container.
Like any great plumber we suggest you roll up your sleeves and get under the sink, or in this case back in the Pipes Editor to see what's going wrong.
As a first step, we suggest you make sure the data you are requesting is active, in other words if the first Input in your Pipe is a feed make sure that feed is returning content. Try copy and pasting the feed URL into your browser or aggregator and seeing what you get.
Once you have confirmed that the feeds in your Pipe are active, you can use the Debugger to figure out where things are going wrong. Try starting at the top of the Pipe and examining the output along every step until you've found the problem.
Whenever possible, simplify your Pipe by connecting as few modules as possible. Start with a basic Pipe and build it up gradually, checking at each step to make sure things still work.
When all else fails, use our Feedback mechanism. We listen and respond and want your Pipe to flow. And if anything has gone wrong on our end, we'll make sure you hear about it promptly.
Either the Pipe changed, or the data flowing into it changed. If you're using someone else's Pipe keep in mind the publisher can change, break or delete a Pipe without notice. If you rely on someone else's published Pipe to do something, it's often a good idea to clone that Pipe so that you have your own version of it in case they make unexpected changes.
Since Pipes are dynamic objects, their behavior will also change when the content flowing into them changes. Check that the upstream feeds are still providing the kind of data they used to.
Pipes caches all the feeds that it visits and tries hard not to download feeds from the same site too often. To help Pipes out, be sure your feed is properly setting the Last-Modified, ETag or Expires fields. Pipes will honor any of these standard HTTP headers.
There are three ways you can prevent your feed content from being used within a Yahoo! Pipe:
Configure your web server to block the user agent "Yahoo Pipes". For example, to block Pipes in Apache, add this to your virtual host block in httpd.conf:
SetEnvIfNoCase User-Agent "Yahoo Pipes" noPipes
<Limit GET POST>
Order Allow,Deny
Allow from all
Deny from env=noPipes
</Limit>
Add the following meta tag to your syndicated feed:
<meta xmlns="http://pipes.yahoo.com" name="pipes" content="noprocess" />
Pipes will ignore the content of any feed containing this tag, even thought it will still need to fetch it from your server (since we have to read the feed in order to see the tag).
Send email to pipes-optout@yahoo-inc.com with a list of the feed URLs you want blocked, along with contact information so we can confirm that you are the owner of those feeds. It can take a few days to block your feeds.
Because Pipes is not a web crawler (the service only retrieves URLs when requested to by a Pipe author or user) Pipes does not follow the robots exclusion protocol, and won't check you robots.txt file.
In order of preference we recommend: Firefox, IE7, Webkit, and Safari.
Pipes is known not to work in Opera. Safari has minor issues. IE6 currently has troubles.
Pipes is a free Yahoo! service. If you want to build your own Pipe you need a Yahoo! ID. If you don't already have one get one here.
To sign in to your Pipes account, go to: http://pipes.yahoo.com
Then click the "Sign In" link in the top right hand corner.
You can sign out of your Pipes account on any page but the Editor. Just click the "Logout" link in the top right hand corner next to where you see your username.
If you wish to report an incident please contact: pipes-abuse [at] yahoo-inc.com.
If you would like to partner with Pipes please contact our Business Development team at:
pipes-bd [at] yahoo-inc.com.
If you provide a service that uses Pipes heavily you may notice that you start getting "999 Errors" from pipes.yahoo.com. There's an easy fix, contact our Business Development team at:
pipes-bd [at] yahoo-inc.com.