Only allow script access to a file iis7.5 - windows

Question

I have a file (called 'log.html') on my iis7.5 server that I would like my PHP installation to be able to access and write to, but I do not want anybody to access the file directly, for example typing in 'http://computername/log.html' (I am on a LAN).
How can I prevent users from accessing it but allow php to see it?
When using the web.config file suggested below, I get this error:

Answer 1

You can use IIS URL Rewrite and create a Request Blocking Rule to prevent access over HTTP:
For example:
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.webServer>
<rewrite>
<rules>
<rule name="BlockLogFile"
patternSyntax="Wildcard"
stopProcessing="true">
<match url="*" />
<conditions>
<add input="{URL}" pattern="/log.html" />
</conditions>
<action type="CustomResponse"
statusCode="403"
statusReason="Forbidden: Access is denied."
statusDescription="This is sekret!" />
</rule>
</rules>
</rewrite>
</system.webServer>
</configuration>

Answer 2

I think that I may have answered my own question! I still need to test it a bit more, and perhaps if it does not work completely then someone could correct me:
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.webServer>
<httpProtocol>
<customHeaders>
<add name="cache-control" value="no-store, no-cache, must-revalidate, max-age=0" />
</customHeaders>
</httpProtocol>
<staticContent>
<clientCache cacheControlMode="DisableCache" />
</staticContent>
<security>
<requestFiltering>
<denyUrlSequences>
<add sequence="log.html" />
</denyUrlSequences>
</requestFiltering>
</security>
</system.webServer>
</configuration>
The cache control bit prevents the browser from caching anything that it returned.
Hope this helps somebody else! I am still very new to this, so you might be able to get around this.