Preventing client-side caching

When you test performance, ensure that you are not serving files from the local cache to Flash Player. Otherwise, this can give false results about download times. Also, during development and testing, you might want to change aspects of the application such as embedded images, but the browser continues to use the old images from your cache.

If the date and time in the If-Modified-Since request header matches the data and time in the Last-Modified response header, the browser loads the SWF file from its cache. Then the server returns the 304 Not Modified message. If the Last-Modified header is more recent, the server returns the SWF file.

You can use the following techniques to disable client-side caching:

Delete the Flex files from the browser's cache after each interaction with your application. Browsers typically store the SWF file and other remote assets in their cache. On Microsoft Internet Explorer, for example, you can delete all the files in c:/Documents and Settings/username/Local Settings/Temporary Internet Files to force a refresh of the files on the next request.
Set the HTTP headers for the SWF file request to prevent caching of the SWF file on the client. The following example shows how to set headers that prevent caching in JSP:// Set Cache-Control to no-cache.
response.setHeader("Cache-Control", "no-cache");
// Prevent proxy caching.
response.setHeader("Pragma", "no-cache");
// Set expiration date to a date in the past.
response.setDateHeader("Expires", 946080000000L); //Approx Jan 1, 2000
// Force always modified.
response.header("Last-Modified", new Date());
Invalidate all items in the client cache by making a change to the flex-config.xml file and saving it. This file stores all the options that the web-tier compiler uses. When the file changes, Adobe Flex Data Services recompiles the application SWF file the next time the MXML file is requested.
Delete the cache.dep file in the /WEB-INF/flex/ directory. This forces the server to invalidate all items in its cache.
Use the Flex Data Services server's caching functionality to control client-side caching. You can set the number of files to cache to 0, which means that Flex Data Services does not cache any files. Every request results in a recompilation. Because the SWF file has a newer data-time stamp, the server sends a new SWF file to the requesting client and the file is never read from the browser's cache. To do this, you set the value of the content-size property in the flex-webtier-config.xml file to 0 as the following example shows:

<cache>
    <content-size>0</content-size>

    <http-maximum-age>1</http-maximum-age>
    <file-watcher-interval>1</file-watcher-interval>

</cache>

Add the recompile=true query string parameter to your request to force a recompile of the application