[Building Sakai] Loading PDFs in Chrome

[Matthew Buckett]

We've recently started seeing a problem with Google Chrome not
displaying PDFs correctly. The first time you load a PDF it will
display correctly, if you then refresh the browser it will display an
error saying "Failed to load PDF Document". I've uploaded an example
to:

https://qa10.longsight.com/access/content/public/Google.pdf

which exhibits this problem. Uploading to a non Sakai webserver
results in the file working correctly:

http://users.ox.ac.uk/~buckett/Google.pdf

If you open developer tools and disable the cache then it loads
correctly every time. I'm running Chrome 39 and it also happens on
Chrome Canary 41. I found an old copy of Chrome 37 in a VM and
everything works correctly there between reloads. My guess is that
Chrome 38 was also OK, but I don't have a copy to test with.

One difference between the two webservers is that the working one
generates ETags which Chrome uses when it loads the page a second
time. Anyone got any ideas?

-- 
  Matthew Buckett, VLE Developer, IT Services, University of Oxford