Check HTTP Response Headers#

For non-JSON requests, in case of an error, highlighting service will return HTTP header X-Highlighter-ErrorMsg with the error message.

Check Log File#

Highlighter keeps a log of all handled requests and any error that occurred. Default path to the log file is logs/highlighter.log relative to the server's installation directory.

To change location of the log file, edit the log configuration file logback.xml located in <highlighter>/conf/. You can specify full path to location file — just make sure that the server process running Highlighter has write access to the file.


When contacting Highlighter support, please always include your custom application.conf file as well as highlighter.log file.


Q: Getting message: "Unexpected server response while retrieving PDF" in PDF.js viewer

You may be affected by CORS restrictions — especially if you are still accessing PDF Highlighter on its default port 8998.

If PDF document and viewer have different HTTP origins (which include protocol, host name, and port), you need to either:

a) Update the configuration of your web server to return CORS headers when serving documents, or...

b) Configure the reverse proxy on your web server to proxy path /highlighter to Highlighter service running on port 8998.

We generally recommend the later — see Reverse Proxying Highlighter for details.

Q: I modified Highlighter Server configuration, but the changes seem to have no effect. Why?

After changing application.conf, you need to restart Highlighting service.

If your changes affect how documents are highlighted, you may need to delete results cache.

If you modified text analysis option, delete search index.

Q: How to delete Highlighter Server cache?

By default, Highlighter saves its data files under highlighter-cache directory below system's temp folder.

To clear highlighting results, delete all files in the results sub-folder.

To delete search index and document analysis cache, delete all files/folders under index. (Index can be deleted only when Highlighter is stopped.)

Q: Highlighter startup fails with error “java.lang.IllegalStateException: Parent for temp dir not configured correctly: writeable=false” although I set tmpDir option in the config

The exception is thrown by the embedded web server before Highlighter was initialized so option tmpDir wasn't picked up.

Try enabling option in file bin/highlighter-service.vmoptions. That will change default temp directory on the process level.