HTTP response caching

Question

I want to ensure that my servet's response is never cached by the broswer, such that even if two identical requests are made (a nanosecond apart), the server is always contacted. Is this the correct way to achieve this:

class MyServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response) {
        response.setHeader("Cache-Control", "no-cache");
    }
}

Thanks, Don

Solution 1

No, that's not the correct way. Here is the correct way:

response.setHeader("Cache-Control", "no-cache, no-store, must-revalidate"); // HTTP 1.1.
response.setHeader("Pragma", "no-cache"); // HTTP 1.0.
response.setDateHeader("Expires", 0); // Proxies.

You'll probably see someone else suggesting other entries/attributes, but those are completely irrelevant when at least the above are mentioned.

Don't forget to clear your browser cache before testing after the change.

See also:

• Caching tutorial for webmasters
• Making sure a page is not cached across all browsers

Solution 2

We use:

    // HTTP 1.1
    response.setHeader("Cache-Control", "private, no-store, no-cache, must-revalidate");
    // HTTP 1.0
    response.setHeader("Pragma", "no-cache");

Solution 3

According to microsoft, these headers are required for IE:

• Cache-Control;
• Pragma;
• Expires (that should be negative);

Example:

Pragma: no-cache
Cache-Control: no-cache
Expires: -1

Comments

[Illarion Kovalchuk]

In addition to before said, I would suggest to do this not in servlet, but in filter, placed before other filters/servlets, so that you can add no-caching to the whole application, without need to add or call this "response.set.." in each of servlets.

[flup]

But some clients need the longer list. Like java 1.7 applets. See stackoverflow.com/questions/17181129/…