CSS Does Not Load With 500 Error When Using Non-English Language in WebSphere 7 Using IIS WebSphere Plugin

Question

I am having an issue with an application (Jasper Reports Server) hosted on WebSphere behind an IIS web server.

When loading a web page, it attempts to load the CSS which generates a 500 error and is unable to load the CSS. This only occurs when the clients language is something other than English. Eg If I use IE and change the language to only include Japanese I can reproduce the error.

In the WebSphere IIS plugin logs, the following gets generated:

[Tue Nov 24 09:44:37 2015] 000014e0 00000dcc - ERROR: ESI: esiResponseCreate: invalid Last-Modified header value: 0xffffffff

When I look up the error, it doesn't provide any help other than contact IBM support or workaround being to add the English language in.

I have also set the logs to TRACE but don't see anything helpful so far.

I can also run another Fiddler (HTTP network trace) to provide more information but will need a suggestion on what to look for.

This seems like a configuration issue because another application (Proprietary) we are running on the same configuration loads the CSS fine with the other language.

Answer 1

It seems to me that your java application likely sets its own Last-Modified header on the HTTP response but (incorrectly) translates the value into some local language. The spec does not permit a localized date string.

You can verify by enabling TRACE or DETAIL level logging in plugin-cfg.xml, or just hit the app directly in the JVM and look at the Last-Modified returned.