Stan, we have been playing with this concept lately to trigger some of our integrations.
Have a look at the webMethods Flat File Schema Developers Guide (ISFlatFileSchemaGuide.pdf). The section “Submitting a Flat File to Integration Server via FTP” will explain how to do what you want.
Just a couple tips. Make sure you connect to the FTP port with an ID/PW that has the appropriate privileges. When I opened my FTP connection to the I.S. FTP port I used the id Default (no password). I did a put of my trigger text file and got the following error:
553 ‘trigFile.txt;application:x-wmflatfile’: cannot write.
If you get this error you need to either login with an id/pw that has enough privileges to run the flow services, or adjust the ACL privileges within the flow service.
If you want to pass data from the file into the flow service, your service needs to specify an input value called ffdata (type Object). Your flow service will then have to convert the Object into a String or Values. For example, you can use the built in services:
this will convert your input stream object into a String. There are other built in services available to convert the stream (eg. pub.flatFile:convertToValues)
I hope this helps.