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From André Warnier (tomcat)>
Subject Re: loading images through a Servlet
Date Fri, 02 Oct 2015 14:38:26 GMT
Chris, you're kind of breaking down an open door here.
Bill was already at the stage of congratulating himself and dreaming of his retirement 
plan, following his discovery of a brilliant and innovative solution.
Better to start from the beginning of the thread..

On 02.10.2015 16:30, Christopher Schultz wrote:
> Hash: SHA256
> Bill,
> On 10/2/15 5:04 AM, Bill Ross wrote:
>> Thanks Andre for the well-considered reply. To Thad - thanks, I
>> also asked on stackoverflow after here.
>> I believe I have solved the obfuscation problem independent of the
>> javascript issue. What I just got working is logically:
>> img.src = "/images/" + /servlet/getnext(params)
>> Where I now have a Servlet at /images that serves the file, thanks
>> to a generous coder at stackoverflow. I'll post the nicely designed
>> code here if anyone wants.
> Why not just use the DefaultServlet... that's what it's job already
> is. Or, do you need an image from a database or whatever?
>> I am adding a table to map random hashes to file names. I'll
>> insert there and have getnext() return the hash instead of the file
>> name. The new Servlet I just added will look up the hash, check the
>> age of the record and refuse it if older than a second, and then
>> serve up the mapped file from the filesystem with current date and
>> some flippant random file name in the headers.
> You could do your security-checking, and then simply forward() to the
> resource, then let the DefaultServlet actually serve the bytes. That
> allows you to use range-requests, etags, if-modified-since, and all
> that other good stuff.
>> So as far as I can see, the only thing not obfuscated is the image
>> itself and my ego, which is harmless here.
> What do you need to obfuscate?
>>> I can think of even more hare-brained schemes where for instance
>>> some Ajax function of yours could open a websocket connection to
>>> the server, and receive a stream of image objects from the server
>>> over that single connection and "plug" them into the page as
>>> appropriate.  But any kind of thing like that would start to
>>> deviate seriously from standard practices, and need a serious
>>> effort of development and debugging before it could be considered
>>> as "production-level".
>> This is exactly what I was fishing for, and I thought maybe it had
>> been solved in some javascript library.
> Do you need the image to be in an Image object, or do you want to put
> it into an <img> on the screen? If the latter, just change the value
> of the 'src' of the <img> and the browser will re-load the image from
> the server.
> - -chris
> Comment: GPGTools -
> 74ql5SalOtbERrTvyY72d4wHjlnWUYJCJeJOTWyDU3grJsG7OBxHpiWEQEI5c9GV
> xEhhGrlI1vOIdJ3gZRCgnrPDV8pdXTS4Sg8zEuLpW5ITRLEJsnHQz6yJDkbLofYz
> w9ACt/Dllv/kcJPHrIu9+J5xgLAEUPKIHuu1mM9TkTWeSYepuR8grm3A2GFO999D
> +5MIkd/XpkfTK88/yGP6Q2xtXgXAtnI5Ug0e5S72gkGFRsHYV5iWb9yBRoji7W09
> G1uOJPm3xiCED2bLsiFBZmhgv/YrmCoVx4EbLnsYO/92tkHT1+2zly2bmKZc/AoC
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> G/hURioQXqcICmslbbhw9QwINuRWz7gpcp+Ll7Jj+3furtxYQwv6IB/qJSWSi/Ih
> =5ruo
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