How do I set the cachability of static files in IIS?

Question

I have some static images in a folder on my IIS 6-based website that I want to be downloaded as little as possible (to preserve bandwidth). I've set the Content Expiration to expire after 30 days. Is there anything else I can do in IIS to try to maximize the caching by browsers, proxy, and gateway caches?

Such as adding a Cache-Control header? Anything else?

Answer 1

http://www.galcho.com/Blog/PermaLink.aspx?guid=490f3c31-1815-40fc-a871-5d6899fa35e0 This is a blog post covering the following:

1. Allow overriding static content setting
2. set cache settings using following commands
3. Cache it on client

Answer 2

Here's my answer from this question: http://stackoverflow.com/questions/102215/expires-in-http-header-for-static-content-how-to

@ECHO OFF 
REM ---------------------------------------------------------------------------
REM Caching - sets the caching on static files in a web site
REM syntax 
REM     Caching.CMD 1 d:\sites\MySite\WWWRoot\*.CSS
REM 
REM   %1 is the WebSite ID
REM   %2 is the path & Wildcard - for example, d:\sites\MySite\WWWRoot\*.CSS
REM   _adsutil is the path to ADSUtil.VBS
REM ---------------------------------------------------------------------------

SETLOCAL
REM *******
REM SET THIS TO POINT TO adsutil.vbs - TYPICALLY c:\inetpub\adminscripts\adsutil.vbs
REM *******
SET _adsutil=D:\Apps\Scripts\adsutil.vbs

FOR %%i IN (%2) DO (
  ECHO Setting Caching on %%~ni%%~xi
  CSCRIPT %_adsutil% CREATE W3SVC/%1/root/%%~ni%%~xi "IIsWebFile"
  CSCRIPT %_adsutil% SET    W3SVC/%1/root/%%~ni%%~xi/HttpExpires "D, 0x69780"
  ECHO.
)

Which sets the caching value for each CSS file in a web root to 5 days, then run it like this:

Caching.CMD 1 \site\wwwroot\*.css
Caching.CMD 1 \site\wwwroot\*.js
Caching.CMD 1 \site\wwwroot\*.html
Caching.CMD 1 \site\wwwroot\*.htm
Caching.CMD 1 \site\wwwroot\*.gif
Caching.CMD 1 \site\wwwroot\*.jpg

Kind of painful, but workable.

BTW - to get the value for HttpExpires, set the value in the GUI, then run

AdsUtil.vbs ENUM W3SVC/1/root/File.txt

to get the actual value you need