I'm trying to create a tool for scientists to BATCH download multiple fastq files from EBI based on starting list of SRA-ID's. The EBI-SRA tool seems to only take one ID at a time.
 
Proposed approach:
 
Defin workflow with two steps.
 
Step1: Get list of ID's from user. Lookup FTP/URL for each ID.
 
Step2: Batch download the URL's using a copy of the "upload file" workflow step.
I'm trying to prepopulate the "URL/Text" box with the list of FTP-URLS from step 1. This way the user doesn't have to cut/paste text from Step #1.  I found the thead on the undocumented dynamic_options functionality. However, not sure that will help here.  
 
Question/Discussion
1) Would appreciate any pointers/examples on how to pre-populate the text area of a workflow input step based on the output from a prior step.
2) This approach seems hacky, so would also love to hear suggestions on a better approach.
 
Thanks in advance,
Dave