Excel Tools Data Subset Export Returning HTTP 500

Question

The download links in several reports in our production environment have started returning HTTP 500 errors when clicked. This seems to be occurring for all users and is not isolated to a single report. 
 The download link is driven by the Excel Tools data subset export. The related export process is completing successfully and I am not seeing any errors in the process, but when I look in the logs I see this whenever someone tries to use the link: 
 17:38:10,332 INFO [stdout] (ajp-/0.0.0.0:8009-32) 2017-08-15 17:38:10,332 [ajp-/0.0.0.0:8009-32] ERROR com.appiancorp.ap2.PortalResponse - Error: 500 
 17:38:43,719 INFO [stdout] (ajp-/0.0.0.0:8009-32) 2017-08-15 17:38:43,719 [ajp-/0.0.0.0:8009-32] ERROR com.appiancorp.ps.exceltools.servlet.ExportDataSubsetToExcelFromProcessServlet - Expected 898 but found 97 
 17:38:43,719 INFO [stdout] (ajp-/0.0.0.0:8009-32) java.security.InvalidParameterException: Expected 898 but found 97 
 I am not sure how to decode these errors, so any help in this area would be appreciated.

saurabhp0002 · Accepted Answer

This Problem will occur only for the Developer who were using "Getdatasubsetdownloadlinkfromprocess" function from older plugin which is "com.appiancorp.ps.plugins.downloaddatasubsetfromprocess-1.2.1". 
As Appian has deprecated the this one and enabled excel tools having all functionality where as kept the function name as same as earlier. It starts failing. 
It is failing as both of the plugins have CDT name as "ExportableDataSubset" where as Name Space is different. for exceltools it is {urn:com:appian:ps:excel:types}ExportableDataSubset and downloaddatasubset it is {urn:appian:plugin:datasubsetdownload:types}ExportableDataSubset. 
 
If Developer is migrating from downloaddatasubsetprocess to excel tool make sure that you remap the correct CDT in process and Expression to get rid of this error.

Arpit Bhargava · Answer

Hi, 
 
You have to take the field name same as you have in the cdt of which data is exporting. So please make sure to check the field names