IIS Compression + Flex 3.0 = Bad Web App

Flex / AIR , Other Tech. Add comments

We recently had a problem w/some of our live Flex apps.  They would simply hang during preloading.  But not always.  The browser had to be Firefox.  And only on select servers.  And only certain apps.  And only in production--never in dev.

After quite a bit of reflection and frustration, we narrowed it down to IIS 6 compression settings.  Turning off IIS compression for .swf files eliminates the problem.  (Too bad, b/c it's easy to hit 700Kb+ when you start embedding large graphics, even w/small apps.)

Our theory is that IE uses gzip to decompress the file (the same algorithm used by IIS to compress the file).  However, Firefox uses deflate.  And apparently the two rountines to not yield the same sequence of bits after decompressing a large binary block.  Flex bug?  Deflate bug?

Adobe has logged this issue, and even placed it in their release notes for Flex 3.  However, they claim it only happens on the first load, and after it is cached, the app loads fine.  This was definitely not our experience.

2 responses to “IIS Compression + Flex 3.0 = Bad Web App”

  1. Adam Says:
    We had this same issue - but only with firefox on the mac, and we are using IIS 7
  2. karan@gmail.com Says:
    This is a cool screen idea ! It is very interesting indeed.Thank you for your info.i love to read all info.

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