IIS 8.5 cache issue on rewrite if file not exists - iis

Question

I need to achieve in IIS the following:
check for changed .txt files in dir with url http://server/dir/test.txt without cache
rewrite url to empty.txt if file does not exist
My configuration:
<rewrite>
<rules>
<rule name="test-txt" patternSyntax="Wildcard" stopProcessing="true">
<match url="*.txt" ignoreCase="false" />
<conditions>
<add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
</conditions>
<action type="Rewrite" url="empty.txt" />
</rule>
</rules>
</rewrite>
<caching>
<profiles>
<add extension=".txt" policy="DisableCache" kernelCachePolicy="DisableCache" />
</profiles>
</caching>
If file is changed, I get code 200 and actual content. Works as expected.
If file not changed - 304. Works as expected.
If file is deleted, after first check I get error 404.0. Why?
After second request I get code 200 and content of empty.txt. Works as expected.
If I create file at that moment, it works as expected. But if make requests in short time intervals (every 3-4 seconds), it doesn't matter any more if file test.txt exists or not, I get code 304 or content of empty.txt if I change it. But if I stop requesting file for some minutes, it works again as expected.
It looks like IIS has some sort of cache for static file checking. How to make it work as expected with static files only? (and without getting error 404 if possible)

Answer 1

It is not output caching, its just about browser cache.
So if you want to prevent cache for specific folder, please place this in the root web.config of your website/application. In this case, you have to disable location path for both example.txt and dir directory
<location path="dir">
<system.webServer>
<staticContent>
<clientCache cacheControlMode="DisableCache" />
</staticContent>
</system.webServer>
</location>
<location path="empty.txt">
<system.webServer>
<staticContent>
<clientCache cacheControlMode="DisableCache" />
</staticContent>
</system.webServer>
</location>
If you want to disable browser cache for all site, please just set
<clientCache cacheControlMode="DisableCache" />
without location attribute.
Your rule works fine on my side, so you just have to disable client side cache for the required folder/file.