Troubleshooting - Data Format Extension (DFE)

This section describes troubleshooting tasks for Vuser scripts that contain DFE functionality.

Replay log: Warning -27040: Data Format Extension: Convert: Empty string returned from extension {Extension name}

When you replay a Vuser script that contains DFE functionality, various messages are added to the Replay log in VuGen's Output pane. The above message indicates that when the Vuser script was replayed, the result of the specified web_convert_from_formatted step in the script was an empty string. For some DFEs, returning an empty string from a web_convert_from_formatted step is the correct behavior. However, if the Vuser script includes GWT-DFE functionality, the above message may indicate one or both of the following:

  • Some of the required classpath files are not included in the runtime settings for the Vuser script.
  • Some of the required classpath files do not exist in the specified location on the Load Generator.

For details on how to resolve these issues, see Implementing GWT-DFE Support.

If you have implemented your own version of DFE, the definition of class HTTPEntity in DfeDefinitions.h file has been updated in LoadRunner 11.50. No code change is required, but all DFE extensions need be recompiled.

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