Bug: stale webstart fails with ClassNotFound

[jamoore]

Will and I have both seen this issue when clicking on webstart for gretzky:

Caused by: java.lang.ClassNotFoundException: org.libjpegturbo.turbojpeg.TJ
        at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
        at com.sun.jnlp.JNLPClassLoader.findClass(JNLPClassLoader.java:345)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:247)

This is caused by the cached JNLP configuration not being re-downloaded for the same URL in Java 1.6. We need to set the "Last-Modified" header.

See:

• ​https://github.com/openmicroscopy/openmicroscopy/pull/912
• ​http://www.coderanch.com/t/200803/JNLP-Web-Start/java/Java-WebStart-cache-jnlp-files

[jamoore]

Workaround: open Java preferences, and delete the cached application.

[jamoore]

Started looking at something like this:

    c = Context(request, context)
    d = datetime.datetime.now()
    rsp = HttpResponse(t.render(c), content_type="application/x-java-jnlp-file")
    rsp["Expires"] = "Sat, 6 May 1995 12:00:00 GMT"
    rsp["Cache-Control"] = "no-store, no-cache, must-revalidate"
    rsp["Pragma"] = "no-cache"
    rsp['Last-Modified'] = d.strftime('%a, %d %b %Y %H:%M:%S GMT')
    return rsp

• ​http://stackoverflow.com/questions/2148454/java-webstart-intermittant-jar-not-updating
• ​http://www.coderanch.com/t/528570/JNLP-Web-Start/java/jnlp-file-updates

but this likely requires quite a bit of testing of the various versions, etc.

[jamoore]

Are there any changes in the Java JARs that we need to worry about for 4.4.9? (i.e. will the configuration have changed?) If so, I think this counts as a blocker. If not, we can likely push unless someone would like to pick it up.

[atarkowska]

no caching for a given UserAgent? ​http://t2410.codeinpro.us/q/5080ea7c4f1eba38a4bf92f4

[atarkowska]

It is possible to add view decorator

from django.views.decorators.cache import never_cache

@never_cache
def myview(request):
    # ...

​https://docs.djangoproject.com/en/1.3/topics/cache/?from=olddocs#controlling-cache-using-other-headers

Result:

Last-Modified = Wed, 18 Sep 2013 12:35:03 GMT
Expires = Wed, 18 Sep 2013 12:35:03 GMT
Content-Type = application/x-java-jnlp-file
Cache-Control = max-age=0

[atarkowska]

fixed in ​https://github.com/aleksandra-tarkowska/openmicroscopy/tree/jnlp_10598